Oligonucleotide compositions and methods of use thereof

Abstract

Among other things, the present disclosure provides oligonucleotides, compositions, and methods useful for targeting HTT. In some embodiments, provided oligonucleotides comprise nucleobase modifications, sugar modifications, internucleotidic linkage modifications and / or patterns thereof, and have improved properties and activities. In some embodiments, the present disclosure provides oligonucleotides, compositions and methods for reducing HTT levels. In some embodiments, the present disclosure provides oligonucleotides, compositions and methods for treating conditions, disorders or diseases such as Huntington's disease.

Description

Attorney Docket No.: 2010581-1667OLIGONUCLEOTIDE COMPOSITIONS AND METHODS OF USE THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States Provisional Application No. 63 / 762,504, filed February 24, 2025, the entirety of which is incorporated herein by reference.BACKGROUND

[0002] Oligonucleotides are useful in various applications, e.g., therapeutic, diagnostic, and / or research applications. For example, oligonucleotides targeting a particular transcript can be useful for treatment of conditions, disorders or diseases related to the transcript or a product encoded thereby.SUMMARY

[0003] In some embodiments, the present disclosure provides oligonucleotides and compositions thereof that have significantly improved properties and / or activities. Among other things, the present disclosure provides technologies for designing, manufacturing and utilizing oligonucleotides and oligonucleotide compositions. Particularly, in some embodiments, the present disclosure provides oligonucleotides and compositions thereof that can reduce levels of HTTla transcripts and products (e.g., polypeptides). In some embodiments, the present disclosure provides oligonucleotides and compositions with high activities and / or improved properties, e.g., knockdown of a HTT (Huntingtin) transcript and / or a product encoded thereby.

[0004] In some embodiments, an oligonucleotide targets a HTT transcript. In some embodiments, the base sequence of an oligonucleotide is or comprise a portion of (e.g., 5-20, 10-20, 15-20, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc. contiguous nucleobases of) a base sequence in Table B-l, wherein each T is independently and optionally replaced with U and vice versa. In some embodiments, the base sequence of an oligonucleotide is or comprises a base sequence in Table B-l, wherein each T is independently and optionally replaced with U and vice versa. In some embodiments, the base sequence of an oligonucleotide is or comprises CTCTGGGTTGCTGGGUCACU, wherein each T is independendy and optionally replaced with U and vice versa.

[0005] In some embodiments, the base sequence of an oligonucleotide is complementary to a portion of the base sequence of a HTT transcript. In some embodiments, an oligonucleotide targets a portion of a HTT transcript. In some embodiments, an oligonucleotide can hybridize to a portion of a HTT transcript. In some embodiments, the length of an oligonucleotide is the same as a portion of a HTT transcript. In some embodiments, a portion is or comprises one or more (e.g., 1-20, 5-20, 10-20, 15-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc.) nucleobases of a specific portion of a HTT transcript, wherein the base sequence of the specific portion is complementary to a base sequence in Table B-l, wherein the base sequence of the specific portion is the same as the base sequence in Table B-l. For example, in some embodiments, the base sequence of a specific portion is complementary to CTCTGGGTTGCTGGGUCACU.Page 1 of 20113318736vlAttorney Docket No.: 2010581-1667In some embodiments, a portion is a characteristic portion of a HTT transcript or HTT transcripts. In some embodiments, a portion is a characteristic portion of a HTTla transcript. In some embodiments, a portion is a characteristic portion of a HTTla mRNA.

[0006] In some embodiments, an oligonucleotide comprises or consists a 5 ’-wing-core-wing-3’, wherein each wing is independently about 2-10 (e.g., 3-10, 4-8, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) nucleobases in length, and the core is about 5-20 (e.g., 7-15, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc.) nucleobases in length. In some embodiments, a wing is about 4-8 nucleobases in length. In some embodiments, a wing is about 5 nucleobases in length. In some embodiments, each wing is about 5 nucleobases in length. In some embodiments, a core is about 10 nucleobases in length. In some embodiments, a sugar in a wing is a modified sugar. In some embodiments, each sugar in a wing is independently a modified sugar. In some embodiments, a wing comprises a 2’-ORw2smodified sugar, wherein Rw2sis optionally substituted C1-6aliphatic. In some embodiments, a wing comprises a bicyclic sugar, e.g., a LNA sugar. In some embodiments, each sugar in the 5 ’-wing is independently a modified sugar. In some embodiments, each sugar in the 5’ -wing is independently a 2’-ORW2Smodified sugar or a bicyclic sugar. In some embodiments, each sugar in the 5’-wing is independently a 2’-OMe modified sugar, a 2’-M0E modified sugar or a bicyclic sugar. In some embodiments, each sugar in the 5’-wing is independently a 2’-OMe modified sugar, a 2’-M0E modified sugar or a LNA sugar. In some embodiments, each sugar in the 5’-wing is independently a 2’-OMe modified sugar or a 2’-MOE modified sugar. In some embodiments, each sugar in the 5 ’-wing is independently a 2’-OMe modified sugar. In some embodiments, each sugar in the 5 ’-wing is independently a 2’ -MOE modified sugar. In some embodiments, each sugar in the 3 ’-wing is independently a modified sugar. In some embodiments, each sugar in the 3’-wing is independently a 2’-ORw2smodified sugar or a bicyclic sugar. In some embodiments, each sugar in the 3’-wing is independently a 2’-OMe modified sugar, a 2’-MOE modified sugar or a bicyclic sugar. In some embodiments, each sugar in the 3’-wing is independently a 2’-OMe modified sugar, a 2’-M0E modified sugar or a LNA sugar. In some embodiments, each sugar in the 3’-wing is independently a 2’-OMe modified sugar or a 2’-M0E modified sugar. In some embodiments, each sugar in the 3’-wing is independently a 2’-OMe modified sugar. In some embodiments, each sugar in the 3’-wing is independently a 2’-M0E modified sugar. In some embodiments, the 5 ’-wing and the 3 ’-wing have different modified sugar patterns. In some embodiments, a 5 ’-wing comprise a modified sugar that is not in the 3 ’-wing. In some embodiments, a 3’-wing comprise a modified sugar that is not in the 5’-wing. In some embodiments, each sugar is a 5’-wing is the same. In some embodiments, each sugar is a 3 ’-wing is the same. In some embodiments, a core comprises one or more natural DNA sugar. In some embodiments, most sugars in a core in a natural DNA sugar. In some embodiments, each sugar in a core is a natural DNA sugar.

[0007] In some embodiments, an oligonucleotide comprises one or more (e.g., about or at least about 5-25, 10-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc.) modified internucleotidic linkages. In some embodiments, about or at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100% of all internucleotidic linkages in an oligonucleotide is independently a modified internucleotidic Page 2 of 20113318736vlAttorney Docket No.: 2010581-1667linkage. In some embodiments, an oligonucleotide comprises a PO internucleotidic linkage. In some embodiments, an oligonucleotide comprises a natural phosphate linkage. In some embodiments, an oligonucleotide comprises a PS internucleotidic linkage. In some embodiments, an oligonucleotide comprises a phosphorothioate internucleotidic linkage. In some embodiments, an oligonucleotide comprises a PN internucleotidic linkage. In some embodiments, an oligonucleotide comprises a phosphoramidate internucleotidic linkage. In some embodiments, an oligonucleotide comprises a phosphoryl guanidine internucleotidic linkage. In some embodiments, a PN internucleotidic linkage is a nOOl internucleotidic linkage. In some embodiments, a PN internucleotidic linkage is -O-P(=O)(-NHSO2CH3)-O-. In some embodiments, an internucleotidic linkage, e.g., a PN internucleotidic linkage, is a non-negatively charged internucleotidic linkage. In some embodiments, an internucleotidic linkage, e.g., aPN internucleotidic linkage, is a neutral internucleotidic linkage. In some embodiments, each internucleotidic linkage is independently a natural phosphate linkage, a phosphorothioate internucleotidic linkage, or a PN internucleotidic linkage. In some embodiments, each internucleotidic linkage is independently a natural phosphate linkage, a phosphorothioate internucleotidic linkage, a nOOl internucleotidic linkage, or a mesyl-phosphoramidate (MsPA) internucleotidic linkage. In some embodiments, a wing comprises a PO internucleotidic linkage. In some embodiments, the 3rdinternucleotidic linkage in a 5 ’-wing is a PO internucleotidic linkage. In some embodiments, the 3rdinternucleotidic linkage in a 5 ’-wing is a natural phosphate linkage. In some embodiments, a 5 ’-wing comprises a phosphorothioate internucleotidic linkage. In some embodiments, the first internucleotidic linkage of a 5 ’-wing is a phosphorothioate internucleotidic linkage. In some embodiments, a 3’ -wing comprises a phosphorothioate internucleotidic linkage. In some embodiments, the last internucleotidic linkage of a 3 ’ -wing is a phosphorothioate internucleotidic linkage. In some embodiments, a core comprises a PS internucleotidic linkage. In some embodiments, a core comprises a phosphorothioate internucleotidic linkage. In some embodiments, each internucleotidic linkage in a core is a phosphorothioate internucleotidic linkage. In some embodiments, a wing comprises one or more PN internucleotidic linkages. For example, in some embodiments, the 2ndinternucleotidic linkage of a 5 ’-wing is a PN internucleotidic linkage (e.g., a nOOl internucleotidic linkage). In some embodiments, the 4thinternucleotidic linkage of a 5’-wing is a PN internucleotidic linkage (e.g., a nOOl internucleotidic linkage). In some embodiments, the 2ndinternucleotidic linkage (which links the 2ndsugar and the 3rdsugar in a 3 ’-wing) of a 3’ -wing is a PN internucleotidic linkage. Among other things, the present disclosure demonstrates that oligonucleotides comprise PN internucleotidic linkages can provide improved activities and / or properties.

[0008] In some embodiments, the present disclosure provides chiral control of linkage phosphorus of oligonucleotides. In some embodiments, an oligonucleotide composition is a chirally controlled oligonucleotide composition. In some embodiments, one or more chiral linkage phosphorus in an oligonucleotide is independently chirally controlled. In some embodiments, each chiral linkage phosphorus is independently chirally controlled. In some embodiments, one or more or all chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 90%, 91%, 92%, 93%, 94%, 95%, 96%,Page 3 of 20113318736vlAttorney Docket No.: 2010581-166797%, 98%, 99% or 99.5%. In some embodiments, diastereomeric purity of an oligonucleotide is about or at least about (DS)nc, wherein DS is about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% and nc is the number of chiral linkage phosphorus in the oligonucleotide. In some embodiments, each phosphorothioate internucleotidic linkage is a wing is Sp. In some embodiments, each PN internucleotidic linkage is Rp. In some embodiments, a core comprises one or more Rp PS internucleotidic linkages. In some embodiments, a core comprises one or more Rp phosphorothioate internucleotidic linkages. In some embodiments, an oligonucleotide comprises one or more RpSpSp, wherein each Rp and Sp is independently configuration of a PS internucleotidic linkage. In some embodiments, an oligonucleotide comprises one or more RpSpSp, wherein each Rp and Sp is independently configuration of a phosphorothioate internucleotidic linkage. In some embodiments, a core comprises one or more RpSpSp, wherein each Rp and Sp is independently configuration of a PS internucleotidic linkage. In some embodiments, a core comprises one or more RpSpSp, wherein each Rp and Sp is independently configuration of a phosphorothioate internucleotidic linkage. In some embodiments, each Rp phosphorothioate internucleotidic linkage is in RpSpSp, wherein each Rp and Sp is independently configuration of a phosphorothioate internucleotidic linkage. In some embodiments, each Rp phosphorothioate internucleotidic linkage is in a core. In some embodiments, each linkage phosphorus of such a RpSpSp is independently bonded to at least one sugar in a core.

[0009] For example, in some embodiments, the present disclosure provides an oligonucleotide, wherein:the base sequence of the oligonucleotide is complementary to a characteristic portion of SEQ ID NO: 1 or 2; andthe oligonucleotide comprises a PN internucleotidic linkage.

[0010] In some embodiments, the present disclosure provides an oligonucleotide, wherein:the base sequence of the oligonucleotide is complementary to a characteristic portion of SEQ ID NO: 1 or 2; andthe oligonucleotide is a gapmer.

[0011] In some embodiments, an oligonucleotide comprises a PS internucleotidic linkage, e.g., a phosphorothioate internucleotidic linkage. In some embodiments, an oligonucleotide comprises a PN internucleotidic linkage (e.g., nOOl, MsPA, etc.). In some embodiments, the present disclosure provides an oligonucleotide, wherein:the base sequence of the oligonucleotide is complementary to a characteristic portion of SEQ ID NO: 1 or 2;the oligonucleotide comprises wing-core-wing, wherein each wing independently comprises a modified sugar and the core comprises DNA sugar; andthe oligonucleotide comprises a PS internucleotidic linkage and a PN internucleotidic linkage.

[0012] In some embodiments, the oligonucleotide comprises wing-core-wing, wherein each wing independently comprises a modified sugar and the core comprises DNA sugar. In some embodiments, each sugar in a wing is independently a 2’-modified sugar. In some embodiments, each sugar in a wing is Page 4 of 20113318736vlAttorney Docket No.: 2010581-1667independently a 2’-0Me modified sugar, 2’ -MOE modified sugar or a bicyclic sugar. In some embodiments, each sugar in a core is a DNA sugar. In some embodiments, an oligonucleotide further comprises a PN internucleotidic linkage (e.g., nOOl, MsPA, etc.). In some embodiments, an oligonucleotide comprises a PO internucleotidic linkage (e.g., natural phosphate linkage), a PS internucleotidic linkage (e.g., a phosphorothioate internucleotidic linkage), and aPN internucleotidic linkage (e.g., nOOl, MsPA, etc.).

[0013] In some embodiments, the present disclosure provides an oligonucleotide, wherein the oligonucleotide is:[moe]([m5C])[Sps].[moe](T)[Rpn].[moe]([m5C])p.[moe](T)[Rpn].[moe](G)[Sps].d(G)[Sps].d(G)[R ps].d(T)[Sps].d(T)[Rps].d(G)[Sps].d(C)[Sps].d(T)[Sps].d(G)[Rps].d(G)[Sps].d(G)[Sps].m(U)[Sps].m(C)[Rp n].m(A)|Sps|.m(C)|Sps].m(U) or a salt thereof, wherein:[moe] represents a 2 ’-MOE ^’-OCEECEhOCHj) modification to a nucleoside;[m5C] represents 5-methyl C;[Sps] represents a Sp PS linkage;[Rpn] represents a Rp PN linkage;p represents a phosphate linkage;d represents 2’-deoxy;[Rps] represents a Rp PS linkage; andm represents a 2’-OMe modification to a nucleoside.

[0014] In some embodiments, the present disclosure provides an oligonucleotide, wherein the oligonucleotide is:[moe]([ni5C])[Ssp].[moe](T)[n001R].[nioe]([m5C])p.[moe](T)[n001R].[moe](G)[Ssp].d(G)[Ssp].d( G)[Rsp].d(T)[Ssp].d(T)[Rsp].d(G)[Ssp].d(C)[Ssp].d(T)[Ssp].d(G)[Rsp].d(G)[Ssp].d(G)[Ssp].m(U)[Ssp].m(C )[n001R].m(A)[Ssp].m(C)[Ssp].m(U) or a salt thereof, wherein:[moe] represents a 2 ’-MOE ^’-OCIECtEOCth) modification to a nucleoside;[m5C] represents 5-methyl C;[Ssp] represents a Sp phosphorothioate linkage;[nOOIR] represents a Ap N-(l,3-dimethylimidazolidin-2-ylidene) phosphoramidate linkage;p represents a phosphate linkage;d represents 2’-deoxy;[Rsp] represents a Ap phosphorothioate linkage; andm represents a 2’-0Me modification to a nucleoside.Among other things, this oligonucleotide comprises a PO internucleotidic linkage (see, e.g., p in [moe]([m5C])p), a PS internucleotidic linkage (see, e.g., [Rsp] and [Ssp]), a PN internucleotidic linkage (see, e.g., [nOOIR]), a 2’-M0E modified sugar (see, e.g., [moe](T)), a 2’-0Me modified sugar (see, e.g., m(U)), a DNA nucleoside (see, e.g., d(C) which is 2’-deoxycytidine), Rp. Sp. Sp (see, e.g., d(G)[Rsp].d(G)[Ssp].d(G)[Ssp]), a 2’-MOE modified sugar wing, a 2’-0Me modified sugar wing, and a DNA Page 5 of 20113318736vlAttorney Docket No.: 2010581-1667sugar core.

[0015] In some embodiments, the present disclosure provides oligonucleotide compositions. In some embodiments, an oligonucleotide composition is a stereorandom composition. In some embodiments, an oligonucleotide composition is a chirally controlled oligonucleotide composition. In some embodiments, an oligonucleotide composition comprises a pre-determined level of an oligonucleotide. In some embodiments, an oligonucleotide composition comprises a higher level of an oligonucleotide compared to a stereorandom composition. In some embodiments, an oligonucleotide composition comprises a higher level of an oligonucleotide compared to a preparation prepared utilizing p-cyanoethyl phosphoramidites (CEP). In some embodiments, a composition is a pharmaceutical composition. In some embodiments, a composition is a pharmaceutical composition, comprising an oligonucleotide and a pharmaceutically acceptable carrier.

[0016] In some embodiments, the present disclosure provides methods for reducing levels of HTT transcripts and / or products thereof. In some embodiments, the present disclosure provides methods for reducing levels of HTT transcripts and / or nucleic acid products thereof. In some embodiments, the present disclosure provides methods for reducing levels of HTT transcripts and / or mRNA products thereof. In some embodiments, the present disclosure provides methods for reducing levels of products encoded by HTT transcripts, e.g., a HTT polypeptide. In some embodiments, the present disclosure provides methods for reducing levels of HTT aggregates which comprise HTT transcripts and / or HTT polypeptides. In some embodiments, an aggregate comprises a HTT transcript. In some embodiments, an aggregate comprises a HTT polypeptide. In some embodiments, a HTT polypeptide comprise expanded polyQ. In some embodiments, a HTT polypeptide comprises PGPAVAEEPLHRP. In some embodiments, a method comprises contacting a HTT transcript with an oligonucleotide, wherein the oligonucleotide can hybridize to the HTT transcript. In some embodiments, a method comprises contacting a HTT transcript with an oligonucleotide, wherein the base sequence of the oligonucleotide is complementary to the base sequence of the HTT transcript or a portion thereof. In some embodiments, the base sequence of an oligonucleotide is fully complementary to an equal length portion of the base sequence of a HTT tra risen pt. In some embodiments, the present disclosure provides methods for reducing levels of HTT transcripts and / or products encoded thereby in a system, comprising administering or delivering to the system an oligonucleotide or composition as described herein. In some embodiments, the present disclosure provides methods for reducing levels of HTT transcripts in a system, comprising administering or delivering to the system an oligonucleotide or composition as described herein. In some embodiments, the present disclosure provides methods for reducing levels of HTT polypeptides in a system, comprising administering or delivering to the system an oligonucleotide or composition as described herein. In some embodiments, die present disclosure provides metfiods for reducing levels of HTT aggregates in a system, comprising administering or delivering to the system an oligonucleotide or composition as described herein. In some embodiments, the present disclosure provides methods for delaying onset of, or slowing down formation of, HTT aggregates in a system, comprising administering or delivering to the system an oligonucleotide or composition as described herein. In some embodiments, a system is or comprises a cell.Page 6 of 20113318736vlAttorney Docket No.: 2010581-1667In some embodiments, a system is or comprises a tissue, e.g., a tissue in brain. In some embodiments, a system is or comprises an organ, e.g., brain or a portion thereof. In some embodiments, a system is or comprises a sample. In some embodiments, a system is or comprises an organism. In some embodiments, a system is or comprises a mammal. In some embodiments, a system is a subject. In some embodiments, a system is a human.

[0017] In some embodiments, the present disclosure provides methods for preventing a condition, disease or disorder, comprising administering or delivering to a subject susceptible thereto an oligonucleotide or composition as described herein. In some embodiments, the present disclosure provides methods for treating a condition, disease or disorder, comprising administering or delivering to a subject suffering therefrom an oligonucleotide or composition as described herein. In some embodiments, a condition, disease or disorder is associated with a HTT mutation, e.g., an expanded CAG repeat as described herein. In some embodiments, a condition, disease or disorder is associated with a HTT transcript and / or a product encoded thereby as described herein. In some embodiments, a condition, disease or disorder is associated with HTT transcripts with an expanded CAG repeat as described herein and / or products (e.g., polypeptides) encoded thereby. In some embodiments, a condition, disease or disorder is Huntington’s disease. In some embodiments, a subject has an expanded CAG repeat in HTT exon 1.

[0018] In some embodiments, a HTT transcript is a full-length HTT transcript. In some embodiments, a HTT transcript comprises exon 1 and exon 2. In some embodiments, a HTT transcript comprises the exon 1-exon 2 junction. In some embodiments, a HTT transcript comprises the exon 64-exon 65 junction. In some embodiments, a HTT transcript comprises a sequence that is complementary to Hs00918174_ml probe. In some embodiments, a HTT transcript comprises a sequence that is or complementary to an about 69-nucleobase sequence starting from position 9046 of NM_002111.8. In some embodiments, a HTT transcript is a full-length HTT transcript which comprises all HTT exons 1 -67. In some embodiments, a HTT transcript is a wildtype HTT transcript. In some embodiments, a HTT transcript is a mutant HTT transcript. In some embodiments, a HTT transcript is a mutant HTT transcript comprising all HTT exons 1-67. In some embodiments, a HTT transcript comprises HTT intron 1 or a portion thereof. In some embodiments, a HTT transcript comprises a portion of HTT intron 1. In some embodiments, a HTT transcript comprises a portion of HTT but not the full HTT intron 1. In some embodiments, a HTT transcript comprises a portion of HTT intron 1 which portion is 2710 bp into intron 1. In some embodiments, a HTT transcript comprises a portion of HTT intron 1 which portion is 7327 bp into intron 1. In some embodiments, a HTT transcript utilizes a cryptic polyA site in intron 1. In some embodiments, a HTT transcript utilizes the polyA site 2710 bp into intron 1. In some embodiments, a HTT transcript utilizes the polyA site 7327 bp into intron 1. In some embodiments, the base sequence of a HTTla transcript comprises SEQ ID NO: 1 or a characteristic portion thereof. In some embodiments, the base sequence of a HTTla transcript comprises SEQ ID NO: 2 or a characteristic portion thereof. In some embodiments, a HTT transcript comprises UUGCAAGUCUGUCAUCUUUGUCUAACUUCCUA or a characteristic portion thereof. In some Page 7 of 20113318736vlAttorney Docket No.: 2010581-1667embodiments, a HTT transcript comprises UUGCAAGUCUGUCAUCUUUGUCUAACUUCCUA. In some embodiments, a mRNA (e.g., a HTTla mRNA) from such a transcript comprises UUGCAAGUCUGUCAUCUUUGUCUAACUUCCUA. In some embodiments, a mRNA (e.g., a HTT mRNA comprising exon 2) from such a transcript does not contain UUGCAAGUCUGUCAUCUUUGUCUAACUUCCUA.

[0019] In some embodiments, a HTT transcript is a HTTla transcript that comprises exon 1 and a portion of intron 1 but no other HTT exons. In some embodiments, a HTT transcript encodes PGPAVAEEPLHRP. In some embodiments, a transcript is pre-mRNA. In some embodiments, a transcript is mRNA. In some embodiments, a transcript comprising a CAG repeat expansion, e.g., in HTT exon 1. In some embodiments, a transcript comprises (CAG)n wherein n is about 27 or above. In some embodiments, n is about or at least about 27, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200. In some embodiments, n is about 27-35. In some embodiments, n is about 36-39. In some embodiments, n is about 40-50. In some embodiments, n is about 50 or more. In some embodiments, n is about 40-60. In some embodiments, n is about 50 or more. In some embodiments, n is about 60 or more. As those skilled in the art appreciate, the number of repeats may be associated with the age of onset and / or type of conditions, diseases or disorders associated with mutant HTT, e.g., Hunting’s disease. In some embodiments, a HTT polypeptide is a full-length HTT polypeptide which comprises amino acid sequences encoded by one or more HTT exons. In some embodiments, a HTT polypeptide comprises an amino acid sequence encoded by exon 1. In some embodiments, a HTT polypeptide comprises an amino acid sequence encoded by exon 2. In some embodiments, a HTT polypeptide comprises an amino acid sequence encoded by exon 1 and exon 2. In some embodiments, a HTT polypeptide comprises an amino acid sequence encoded by exon 1 and intron 1 or a portion thereof. In some embodiments, a HTT polypeptide comprises PGPAVAEEPLHRP.

[0020] Various technologies can be utilized for administering or delivering an oligonucleotide or composition. In some embodiments, an oligonucleotide or composition is administered or delivered intrathecally. In some embodiments, an oligonucleotide or composition is administered or delivered by direct lumbar injection. In some embodiments, an oligonucleotide is administered or delivered in a pharmaceutical I y acceptable carrier, e.g., a buffer such as aCSF.

[0021] In some embodiments, the present disclosure provides an oligonucleotide or composition as described herein for use in a method as described herein, e.g., for reducing levels of a HTT transcript and / or a product thereof (e.g., a mRNA, a polypeptide, etc.), for reducing levels of HTT aggregates, for preventing or treating a condition, disease or disorder (e.g., Huntington’s disease), etc. In some embodiments, the present disclosure provides an oligonucleotide or composition as described herein for use in manufacturing a medicament or composition for a method as described herein, e.g., for reducing levels of a HTT transcript and / or a product thereof (e.g., a mRNA, a polypeptide, etc.), for reducing levels of HTT aggregates, for preventing or treating a condition, disease or disorder (e.g., Huntington’s disease), etc. In some embodiments, the present disclosure provides use of an oligonucleotide or composition for a method as described herein, e.g.,Page 8 of 20113318736vlAttorney Docket No.: 2010581-1667for reducing levels of a HTT transcript and / or a product thereof (e.g., a mRNA, a polypeptide, etc.), for reducing levels of HTT aggregates, for preventing or treating a condition, disease or disorder (e.g., Huntington’s disease), etc. In some embodiments, the present disclosure provides use of an oligonucleotide or composition for manufacturing a medicament or composition for a method as described herein, e.g., for reducing levels of a HTT transcript and / or a product thereof (e.g., a mRNA, a polypeptide, etc.), for reducing levels of HTT aggregates, for preventing or treating a condition, disease or disorder (e.g., Huntington’s disease), etc.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1. Provided technologies can reduce levels of HTT transcripts. Oligonucleotides were tested at 5 pM, 1 pM or 0.2 pM. Percentage of human HTT or HTTla RNA remaining in cells treated with oligonucleotides or mock (e.g., cells treated with water alone) are shown. See Example 3 for probes for detection.DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0023] Technologies of the present disclosure may be understood more readily by reference to the following detailed description of certain embodiments.Definitions

[0024] As used herein, the following definitions shall apply unless otherwise indicated. For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75th Ed. Additionally, general principles of organic chemistry are described in " Organic Chemistry", Thomas Sorrell, University Science Books, Sausalito: 1999, and " March's Advanced Organic Chemistry", 5th Ed., Ed.: Smith, M. B. and March, J., John Wiley & Sons, New York: 2001.

[0025] As used herein in the present disclosure, unless otherwise clear from context, (i) the term “a” or “an” may be understood to mean “at least one”: (ii) the term “or” may be understood to mean “and / or”; (iii) the terms “comprising”, “comprise”, “including” (whether used with “not limited to” or not), and “include” (whether used with “not limited to” or not) may be understood to encompass itemized components or steps whether presented by themselves or together with one or more additional components or steps; (iv) the term “another” may be understood to mean at least an additional / second one or more; (v) the terms “about” and “approximately” may be understood to permit standard variation as would be understood by those of ordinary skill in the art; and (vi) where ranges are provided, endpoints are included.

[0026] Unless otherwise specified, description of oligonucleotides and elements thereof (e.g., base sequence, sugar modifications, internucleotidic linkages, linkage phosphorus stereochemistry, patterns thereof, etc.) is from 5’ to 3’. As those skilled in the art will appreciate, in some embodiments, oligonucleotides may Page 9 of 20113318736vlAttorney Docket No.: 2010581-1667be provided and / or utilized as salt forms, particularly pharmaceutically acceptable salt forms, e.g., sodium salts. As those skilled in the ail will also appreciate, in some embodiments, individual oligonucleotides within a composition may be considered to be of the same constitution and / or structure even though, within such composition (e.g., a liquid composition), particular such oligonucleotides might be in different salt form(s) (and may be dissolved and the oligonucleotide chain may exist as an anion form when, e.g., in a liquid composition) at a particular moment in time. For example, those skilled in the art will appreciate that, at a given pH, individual internucleotidic linkages along an oligonucleotide chain may be in an acid (H) form, or in one of a plurality of possible salt forms (e.g., a sodium salt, or a salt of a different cation, depending on which ions might be present in the preparation or composition), and will understand that, so long as their acid forms (e.g., replacing all cations, if any, with H+) are of the same constitution and / or structure, such individual oligonucleotides may properly be considered to be of the same constitution and / or structure.

[0027] Aliphatic As used herein, “aliphatic” means a straight-chain (i.e., unbranched) or branched, substituted or unsubstituted hydrocarbon chain that is completely saturated or that contains one or more units of unsaturation (but not aromatic), or a substituted or unsubstituted monocyclic, bicyclic, or polycyclic hydrocarbon ring that is completely saturated or that contains one or more units of unsaturation (but not aromatic), or combinations thereof. In some embodiments, aliphatic groups contain 1-50 aliphatic carbon atoms. In some embodiments, aliphatic groups contain 1-20 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-10 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-9 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-8 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-7 aliphatic carbon atoms. In other embodiments, aliphatic groups contain 1-6 aliphatic carbon atoms. In still other embodiments, aliphatic groups contain 1-5 aliphatic carbon atoms, and in yet other embodiments, aliphatic groups contain 1, 2, 3, or 4 aliphatic carbon atoms. Suitable aliphatic groups include, but are not limited to, linear or branched, substituted or unsubstituted alkyl, alkenyl, alkynyl groups and hybrids thereof such as (cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

[0028] Alkenyl: As used herein, the term “alkenyl” refers to an aliphatic group, as defined herein, having one or more double bonds.

[0029] Alkyl: As used herein, the term “alkyl” is given its ordinary meaning in the art and may include saturated aliphatic groups, including straight-chain alkyl groups, branched-chain alkyl groups, cycloalkyl (alicyclic) groups, alkyl substituted cycloalkyl groups, and cycloalkyl substituted alkyl groups. In some embodiments, alkyl has 1-100 carbon atoms. In certain embodiments, a straight chain or branched chain alkyl has about 1-20 carbon atoms in its backbone (e.g., C1-C20 for straight chain, C2-C20 for branched chain), and alternatively, about 1-10. In some embodiments, cycloalkyl rings have from about 3-10 carbon atoms in their ring structure where such rings are monocyclic, bicyclic, or polycyclic, and alternatively about 5, 6 or 7 carbons in the ring structure. In some embodiments, an alkyl group may be a lower alkyl group, wherein a lower alkyl group comprises 1-4 carbon atoms (e.g., C1-C4 for straight chain lower alkyls).

[0030] Alkynyl: As used herein, the term “alkynyl” refers to an aliphatic group, as defined herein, having Page 10 of 20113318736vlAttorney Docket No.: 2010581-1667one or more triple bonds.

[0031] Analog: The term “analog” includes any chemical moiety which differs structurally from a reference chemical moiety or class of moieties, but which is capable of performing at least one function of such a reference chemical moiety or class of moieties. As non-limiting examples, a nucleotide analog differs structurally from a nucleotide but performs at least one function of a nucleotide; a nucleobase analog differs structurally from a nucleobase but performs at least one funchon of a nucleobase; etc.

[0032] Animal: As used herein, the term “animal” refers to any member of the animal kingdom. In some embodiments, “animal” refers to humans, at any stage of development. In some embodiments, “animal” refers to non-human animals, at any stage of development. In certain embodiments, the non-human animal is a mammal (e.g., a rodent, a mouse, a rat, a rabbit, a monkey, a dog, a cat, a sheep, cattle, a primate and / or a pig). In some embodiments, animals include, but are not limited to, mammals, birds, reptiles, amphibians, fish and / or worms. In some embodiments, an animal may be a transgenic animal, a genetically-engineered animal and / or a clone.

[0033] Aryl: The term “aryl", as used herein, used alone or as part of a larger moiety as in “aralkyl,” “aralkoxy,” or “aryloxy alkyl,” refers to monocyclic, bicyclic or polycyclic ring systems having a total of five to thirty ring members, wherein at least one ring in the system is aromatic. In some embodiments, an aryl group is a monocyclic, bicyclic or polycyclic ring system having a total of five to fourteen ring members, wherein at least one ring in the system is aromatic, and wherein each ring in the system contains 3 to 7 ring members. In some embodiments, each monocyclic ring unit is aromatic. In some embodiments, an aryl group is a biaryl group. The term “aryl” may be used interchangeably with the term “aryl ring.” In certain embodiments of the present disclosure, “aryl” refers to an aromatic ring system which includes, but is not limited to, phenyl, biphenyl, naphthyl, binaphthyl, anthracyl and the like, which may bear one or more substituents. Also included within the scope of the term “aryl,” as it is used herein, is a group in which an aromatic ring is fused to one or more non-aromatic rings, such as indanyl, phthalimidyl, naphthimidyl, phenanthridinyl, or tetrahydronaphthyl, and the like.

[0034] Characteristic portion: As used herein, the term “characteristic portion”, in the broadest sense, refers to a portion of a substance whose presence (or absence) correlates with presence (or absence) of a particular feature, attribute, or activity of the substance. In some embodiments, a characteristic portion of a substance is a portion that is found in the substance and in related substances that share the particular feature, attribute or activity, but not in those that do not share the particular feature, attribute or activity. In certain embodiments, a characteristic portion shares at least one functional characteristic with the intact substance. For example, in some embodiments, a “characteristic portion” of a protein or polypeptide is one that contains a continuous stretch of amino acids, or a collection of continuous stretches of amino acids, that together are characteristic of a protein or polypeptide. In some embodiments, each such continuous stretch generally contains at least 2, 5, 10, 15, 20, 50, or more amino acids. In general, a characteristic portion of a substance (e.g., of a protein, antibody, etc.) is one that, in addition to the sequence and / or structural identity specified Page 11 of 20113318736vlAttorney Docket No.: 2010581-1667above, shares at least one functional characteristic with the relevant intact substance. In some embodiments, a characteristic portion may be biologically active.

[0035] Chiral control: As used herein, “chiral control” refers to control of the stereochemical designation of the chiral linkage phosphorus in a chiral internucleotidic linkage within an oligonucleotide. As used herein, a chiral internucleotidic linkage is an internucleotidic linkage whose linkage phosphorus is chiral. In some embodiments, a control is achieved through a chiral element that is absent from the sugar and base moieties of an oligonucleotide, for example, in some embodiments, a control is achieved through use of one or more chiral auxiliaries during oligonucleotide preparation, which chiral auxiliaries often are part of chiral phosphoramidites used during oligonucleotide preparation. In contrast to chiral control, a person having ordinary skill in the art will appreciate that conventional oligonucleotide synthesis which does not use chiral auxiliaries cannot control stereochemistry at a chiral internucleotidic linkage if such conventional oligonucleotide synthesis is used to form the chiral internucleotidic linkage. In some embodiments, the stereochemical designation of each chiral linkage phosphorus in each chiral internucleotidic linkage within an oligonucleotide is controlled.

[0036] Chirally controlled oligonucleotide composition: The terms “chirally controlled oligonucleotide composition”, “chirally controlled nucleic acid composition”, and the like, as used herein, refers to a composition that comprises a plurality of oligonucleotides (or nucleic acids) which share a common base sequence, wherein the plurality of oligonucleotides (or nucleic acids) share the same linkage phosphorus stereochemistry at one or more chiral internucleotidic linkages (chirally controlled or stereodefined internucleotidic linkages, whose chiral linkage phosphorus is Rp or Sp in the composition (“stereodefined”), not a random Rp and Sp mixture as non-chirally controlled internucleotidic linkages). In some embodiments, a chirally controlled oligonucleotide composition comprises a plurality of oligonucleotides (or nucleic acids) that share: 1) a common base sequence, 2) a common pattern of backbone linkages, and 3) a common pattern of backbone phosphorus modifications, wherein the plurality of oligonucleotides (or nucleic acids) share the same linkage phosphorus stereochemistry at one or more chiral internucleotidic linkages (chirally controlled or stereodefined internucleotidic linkages, whose chiral linkage phosphorus is Rp or Sp in the composition (“stereodefined”), not a random Rp and Sp mixture as non-chirally controlled internucleotidic linkages). Level of the plurality of oligonucleotides (or nucleic acids) in a chirally controlled oligonucleotide composition is pre-determined / controlled or enriched (e.g., through chirally controlled oligonucleotide preparation to stereoselectively form one or more chiral internucleotidic linkages) compared to a random level in a nonchirally controlled oligonucleotide composition. In some embodiments, about l%-100%, (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90-100%, 95-100%, 50%-90%, or about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, or at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) of all oligonucleotides in a chirally controlled oligonucleotide composition are oligonucleotides of the plurality. In some embodiments, about 1 %- Page 12 of 20113318736vlAttorney Docket No.: 2010581-1667100%, (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90-100%, 95-100%, 50%-90%, or about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, or at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) of all oligonucleotides in a chirally controlled oligonucleotide composition that share the common base sequence, the common pattern of backbone linkages, and the common pattern of backbone phosphorus modifications are oligonucleotides of the plurality. In some embodiments, a level is about l%-100%, (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90-100%, 95-100%, 50%-90%, or about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, or at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) of all oligonucleotides in a composition, or of all oligonucleotides in a composition that share a common base sequence (e.g., of a plurality of oligonucleotide or an oligonucleotide type), or of all oligonucleotides in a composition that share a common base sequence, a common pattern of backbone linkages, and a common pattern of backbone phosphorus modifications, or of all oligonucleotides in a composition that share a common base sequence, a common patter of base modifications, a common pattern of sugar modifications, a common pattern of internucleotidic linkage types, and / or a common pattern of internucleotidic linkage modifications. In some embodiments, the plurality of oligonucleotides share the same stereochemistry at about 1-50 (e.g., about 1-10, 1-20, 5-10, 5-20, 10-15, 10-20, 10-25, 10-30, or about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, or at least 1, 2, 3, 4, 5, 6, 7. 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20) chiral internucleotidic linkages. In some embodiments, the plurality of oligonucleotides share the same stereochemistry at about 1 %-100% (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90-100%, 95-100%, 50%-90%, about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, or at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%) of chiral internucleotidic linkages. In some embodiments, oligonucleotides (or nucleic acids) of a plurality share the same pattern of sugar and / or nucleobase modifications, in any. In some embodiments, oligonucleotides (or nucleic acids) of a plurality are various forms of the same oligonucleotide (e.g., acid and / or various salts of the same oligonucleotide). In some embodiments, oligonucleotides (or nucleic acids) of a plurality are of the same constitution. In some embodiments, level of the oligonucleotides (or nucleic acids) of the plurality is about l%-100%, (e.g., about 5%-100%, 10%-100%, 20%-100%, 30%-100%, 40%-100%, 50%-100%, 60%-100%, 70%-100%, 80-100%, 90-100%, 95-100%, 50%-90%, or about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%, or at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%) of all oligonucleotides (or nucleic acids) in a composition that share the same constitution as the oligonucleotides (or nucleic acids) of the plurality. In some embodiments, each chiral internucleotidic linkage is a chiral controlled internucleotidic Page 13 of 20113318736vlAttorney Docket No.: 2010581-1667linkage, and the composition is a completely chirally controlled oligonucleotide composition. In some embodiments, oligonucleotides (or nucleic acids) of a plurality are structurally identical. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%, typically at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 95%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 96%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 97%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 98%. In some embodiments, a chirally controlled internucleotidic linkage has a diastereopurity of at least 99%. In some embodiments, a percentage of a level is or is at least (DS)nc, wherein DS is a diastereopurity as described in the present disclosure (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% or more) and nc is the number of chiral linkage phosphorus as described in the present disclosure (e.g., 1-50, 1-40, 1-30, 1-25, 1-20, 5-50, 5-40, 5-30, 5-25, 5-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more). In some embodiments, a percentage of a level is or is at least (DS)nc, wherein DS is a diastereopurity as described in the present disclosure (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% or more) and nc is the number of chirally controlled internucleotidic linkages as described in the present disclosure (e.g., 1-50, 1-40, 1-30, 1-25, 1-20, 5-50, 5-40, 5-30, 5-25, 5-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more). In some embodiments, a percentage of a level is or is at least (DS)nc, wherein DS is 95%-100%. For example, when DS is 99% and nc is 10, the percentage is or is at least 90% ((99%)10≈ 0.90 = 90%). In some embodiments, level of a plurality of oligonucleotides in a composition is represented as the product of the diastereopurity of each chiral linkage phosphorus. In some embodiments, level of a plurality of oligonucleotides in a composition is represented as the product of the diastereopurity of each chirally controlled internucleotidic linkage in the oligonucleotides. In some embodiments, diastereopurity of an internucleotidic linkage connecting two nucleosides in an oligonucleotide (or nucleic acid) is represented by the diastereopurity of an internucleotidic linkage of a dimer connecting the same two nucleosides, wherein the dimer is prepared using comparable conditions, in some instances, identical synthetic cycle conditions (e.g., for the linkage between Nx and Ny in an oligonucleotide.... NxNy, the dimer is NxNy). In some embodiments, not all chiral internucleotidic linkages are chiral controlled internucleotidic linkages, and the composition is a partially chirally controlled oligonucleotide composition. In some embodiments, a non-chirally controlled internucleotidic linkage has a diastereopurity of less than about 80%, 75%, 70%, 65%, 60%, 55%, or of about 50%, as typically observed in stereorandom oligonucleotide compositions (e.g., as appreciated by those skilled in the art, from traditional oligonucleotide synthesis, e.g., the phosphoramidite method). In some embodiments, oligonucleotides (or nucleic acids) of a plurality are of the same type. In some embodiments, a chirally controlled oligonucleotide composition comprises non-random or controlled levels of individualPage 14 of 20113318736vlAttorney Docket No.: 2010581-1667oligonucleotide or nucleic acids types. For instance, in some embodiments a chirally controlled oligonucleotide composition comprises one and no more than one oligonucleotide type. In some embodiments, a chirally controlled oligonucleotide composition comprises more than one oligonucleotide type. In some embodiments, a chirally controlled oligonucleotide composition comprises multiple oligonucleotide types. In some embodiments, a chirally controlled oligonucleotide composition is a composition of oligonucleotides of an oligonucleotide type, which composition comprises a non-random or controlled level of a plurality of oligonucleotides of the oligonucleotide type.

[0037] Comparable'. The term “comparable” is used herein to describe two (or more) sets of conditions or circumstances that are sufficiently similar to one another to permit comparison of results obtained or phenomena observed. In some embodiments, comparable sets of conditions or circumstances are characterized by a plurality of substantially identical features and one or a small number of varied features. Those of ordinary skill in the art will appreciate that sets of conditions are comparable to one another when characterized by a sufficient number and type of substantially identical features to warrant a reasonable conclusion that differences in results obtained or phenomena observed under the different sets of conditions or circumstances are caused by or indicative of the variation in those features that are varied.

[0038] Cycloaliphatic. The term “cycloaliphatic,” “carbocycle,” “carbocyclyl,” “carbocyclic radical,” and “carbocyclic ring,” are used interchangeably, and as used herein, refer to saturated or partially unsaturated, but non-aromatic, cyclic aliphatic monocyclic, bicyclic, or polycyclic ring systems, as described herein, having, unless otherwise specified, from 3 to 30 ring members. Cycloaliphatic groups include, without limitation, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, cycloheptyl, cycloheptenyl, cyclooctyl, cyclooctenyl, norbornyl, adamantyl, and cyclooctadienyl. In some embodiments, a cycloaliphatic group has 3-6 carbons. In some embodiments, a cycloaliphatic group is saturated and is cycloalky]. The term “cycloaliphatic” may also include aliphatic rings that are fused to one or more aromatic or nonaromatic rings, such as decahydronaphthyl or tetrahydronaphthyl. In some embodiments, a cycloaliphatic group is bicyclic. In some embodiments, a cycloaliphatic group is tricyclic. In some embodiments, a cycloaliphatic group is polycyclic. In some embodiments, “cycloaliphatic” refers to C3-C6 monocyclic hydrocarbon, or C₈-C₁₀ bicyclic or polycyclic hydrocarbon, that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic, that has a single point of attachment to the rest of the molecule, or a C9-C16 polycyclic hydrocarbon that is completely saturated or that contains one or more units of unsaturation, but which is not aromatic, that has a single point of attachment to the rest of the molecule.

[0039] Gapmer: As used herein, the term “gapmer” refers to an oligonucleotide characterized in that it comprises a core flanked by a 5 ’ and a 3’ wing. In some embodiments, in a gapmer, at least one internucleotidic linkage of the oligonucleotide is a natural phosphate linkage. In some embodiments, more than one internucleotidic linkage of the oligonucleotide is a natural phosphate linkage. In some embodiments, a gapmer is a sugar modification gapmer, wherein each wing sugar independently comprises a sugar modification, and Page 15 of 20113318736vlAttorney Docket No.: 2010581-1667no core sugar comprises a sugar modification found in a wing sugar. In some embodiments, each core sugar comprises no modification and are 2 ’-unsubstituted (as in natural DNA). In some embodiments, each wing sugar is independently a 2’ -modified sugar. In some embodiments, at least one wing sugar is a bicyclic sugar. In some embodiments, sugar units in each wing have the same sugar modification (e.g., 2’-OMe (a 2’-OMe wing), 2’ -MOE (a 2’ -MOE wing), etc.). In some embodiments, each wing sugar has the same modification. Core and wing can have various lengths. In some embodiments, a wing is 2, 3, 4, 5, 6, 7, 8, 9, 10 or more nucleosides (in many embodiments, 3, 4, 5, or 6 or more) in length, and a core is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more nucleosides (in many embodiments, 8, 9, 10, 11, 12, or more) in length. In some embodiments, an oligonucleotide comprises or consists of a wing-core-wing structure of 2-9-6, 3-9-3, 3-9-4, 3-9-5, 4-7-4, 4-9-4, 4-9-5, 4-10-5, 4-11-4, 4-11-5, 5-7-5, 5-8-6, 5-9-3, 5-9-5, 5-10-4, 5-10-5, 6-7-6, 6-8-5, or 6-9-2. In some embodiments, an oligonucleotide is a gapmer.

[0040] Effective amount: As used herein, the term “effective amount” means an amount of a substance (e.g., an oligonucleotide, therapeutic agent, composition, and / or formulation) that elicits a desired biological response when administered or delivered. In some embodiments, an effective amount of a substance is an amount that is sufficient, when administered or delivered to a subject suffering from or susceptible to a disease, disorder, and / or condition, to treat, diagnose, prevent, and / or delay the onset of the disease, disorder, and / or condition, or to otherwise produce a biological effect (e.g., increasing or reducing level of a target nucleic acid or a product encoded thereby). As will be appreciated by those of ordinary skill in the art, an effective amount of a substance may vary depending on such factors as the desired biological effect or endpoint, the substance to be delivered, the target cell or tissue, etc. In some embodiments, an effective amount is administered in a single dose; in some embodiments, multiple unit doses are required to deliver an effective amount.

[0041] Heteroaliphatic: The term “heteroaliphatic”, as used herein, is given its ordinary meaning in the art and refers to aliphatic groups as described herein in which one or more carbon atoms are independently replaced with one or more heteroatoms (e.g., oxygen, nitrogen, sulfur, silicon, phosphorus, and the like). In some embodiments, one or more units selected from C, CH, CH2, and CH3 are independently replaced by one or more heteroatoms (including oxidized and / or substituted forms thereof). In some embodiments, a heteroaliphatic group is heteroalkyl. In some embodiments, a heteroaliphatic group is heteroalkenyl.

[0042] Heteroalkyl: The term “heteroalkyl”, as used herein, is given its ordinary meaning in the art and refers to alkyl groups as described herein in which one or more carbon atoms are independently replaced with one or more heteroatoms (e.g., oxygen, nitrogen, sulfur, silicon, phosphorus, and the like). Examples of heteroalkyl groups include, but are not limited to, alkoxy, polyethylene glycol)-, alkyl-substituted amino, tetrahydrofuranyl, piperidinyl, morpholinyl, etc.

[0043] Heteroaryl: The terms “heteroaryl” and “heteroar-”, as used herein, used alone or as part of a larger moiety, e.g., “heteroaralkyl,” or “heteroaralkoxy,” refer to monocyclic, bicyclic or polycyclic ring systems having a total of five to thirty ring members, wherein at least one ring in the system is aromatic and at least one aromatic ring atom is a heteroatom. In some embodiments, a heteroaryl group is a group having 5 to Page 16 of 20113318736vlAttorney Docket No.: 2010581-166710 ring atoms (i.e., monocyclic, bicyclic or polycyclic), in some embodiments 5, 6, 9, or 10 ring atoms. In some embodiments, each monocyclic ring unit is aromatic. In some embodiments, a heteroaryl group has 6, 10, or 14 π electrons shared in a cyclic array; and having, in addition to carbon atoms, from one to five heteroatoms. Heteroaryl groups include, without limitation, thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl, purinyl, naphthyridinyl, and pteridinyl. In some embodiments, a heteroaryl is a heterobiaryl group, such as bipyridyl and the like. The terms “heteroaryl” and “heteroar-”, as used herein, also include groups in which a heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocyclyl rings, where the radical or point of attachment is on the heteroaromatic ring. Non-limiting examples include indolyl, isoindolyl, benzothienyl, benzofuranyl, dibenzofuranyl, indazolyl, benzimidazolyl, benzthiazolyl, quinolyl, isoquinolyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 4H-quinolizinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, and pyrido[2,3-b]-l,4-oxazin-3(4H)-one. A heteroaryl group may be monocyclic, bicyclic or polycyclic. The term “heteroaryl” may be used interchangeably with the terms “heteroaryl ring,” “heteroaryl group,” or “heteroaromatic,” any of which terms include rings that are optionally substituted. The term “heteroaralkyl” refers to an alkyl group substituted by a heteroaryl group, wherein the alkyl and heteroaryl portions independently are optionally substituted.

[0044] Heteroatom'. The term “heteroatom", as used herein, means an atom that is not carbon or hydrogen. In some embodiments, a heteroatom is boron, oxygen, sulfur, nitrogen, phosphorus, or silicon (including oxidized forms of nitrogen, sulfur, phosphorus, or silicon; charged forms of nitrogen (e.g., quaternized forms, forms as iniminium groups, etc.), phosphorus, sulfur, oxygen; etc.). In some embodiments, a heteroatom is silicon, phosphorus, oxygen, sulfur or nitrogen. In some embodiments, a heteroatom is silicon, oxygen, sulfur or nitrogen. In some embodiments, a heteroatom is oxygen, sulfur or nitrogen.

[0045] Heterocycle-. As used herein, the terms “heterocycle,” “heterocyclyl,” “heterocyclic radical,” and “heterocyclic ring", as used herein, are used interchangeably and refer to a monocyclic, bicyclic or polycyclic ring moiety (e.g., 3-30 membered) that is saturated or partially unsaturated and has one or more heteroatom ring atoms. In some embodiments, a heterocyclyl group is a stable 5- to 7-membered monocyclic or 7- to 10-membered bicyclic heterocyclic moiety that is either saturated or partially unsaturated, and having, in addition to carbon atoms, one or more, preferably one to four, heteroatoms, as defined above. When used in reference to a ring atom of a heterocycle, the term "nitrogen" includes substituted nitrogen. As an example, in a saturated or partially unsaturated ring having 0-3 heteroatoms selected from oxygen, sulfur and nitrogen, the nitrogen may be N (as in 3,4-dihydro-2H-pyrrolyl), NH (as in pyrrolidinyl), or+NR (as in N-substituted pyrrolidinyl). A heterocyclic ring can be attached to its pendant group at any heteroatom or carbon atom that results in a stable structure and any of the ring atoms can be optionally substituted. Examples of such saturated or partially unsaturated heterocyclic radicals include, without limitation, tetrahydrofuranyl, tetrahydrothienyl, pyrrolidinyl, piperidinyl, pyrrolinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl,Page 17 of 20113318736vlAttorney Docket No.: 2010581-1667oxazolidinyl, piperazinyl, dioxanyl, dioxolanyl, diazepinyl, oxazepinyl, thiazepinyl, morpholinyl, and quinuclidinyl. The terms “heterocycle,” “heterocyclyl,” “heterocyclyl ring,” “heterocyclic group,” “heterocyclic moiety,” and “heterocyclic radical,” are used interchangeably herein, and also include groups in which a heterocyclyl ring is fused to one or more aryl, heteroaryl, or cycloaliphatic rings, such as indolinyl, 3H-indolyl, chromanyl, phenanthridinyl, or tetrahydroquinolinyl. A heterocyclyl group may be monocyclic, bicyclic or polycyclic. The term “heterocyclylalkyl” refers to an alkyl group substituted by a heterocyclyl, wherein the alkyl and heterocyclyl portions independently are optionally substituted.

[0046] Homology. “Homology” or “identity” or “similarity” refers to sequence similarity between two nucleic acid molecules. Homology and identity can each be determined by comparing a position in each sequence which can be aligned for purposes of comparison. When an equivalent position in the compared sequences is occupied by the same base, then the molecules are identical at that position; when the equivalent site occupied by the same or a similar nucleic acid residue (e.g., similar in steric and / or electronic nature), then the molecules can be referred to as homologous (similar) at that position. Expression as a percentage of homology / similarity or identity refers to a function of the number of identical or similar nucleic acids at positions shared by the compared sequences. In some embodiments, a sequence which is “unrelated” or “non-homologous” shares less than 40% identity, less than 35% identity, less than 30% identity, or less than 25% identity with a sequence described herein. In comparing two sequences, the absence of residues (amino acids or nucleic acids) or presence of extra residues also decreases the identity and homology / similarity. In some embodiments, polymeric molecules (e.g., oligonucleotides, nucleic acids, proteins, etc.) are considered to be “homologous” to one another if their sequences are at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% identical. In some embodiments, polymeric molecules are considered to be “homologous” to one another if their sequences are at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% similar.

[0047] In some embodiments, the term “homology” describes a mathematically based comparison of sequence similarities which is used to identify genes with similar functions or motifs. The nucleic acid sequences described herein can be used as a “query sequence” to perform a search against public databases, for example, to identify other family members, related sequences or homologs. In some embodiments, such searches can be performed using the NBLAST and XBLAST programs (version 2.0) of Altschul, et al. (1990) J. Mol. Biol. 215:403-10. In some embodiments, BLAST nucleotide searches can be performed with the NBLAST program, score=100, wordlength^ 12 to obtain nucleotide sequences homologous to nucleic acid molecules of the disclosure. In some embodiments, to obtain gapped alignments for comparison purposes, Gapped BLAST can be utilized as described in Altschul et al., (1997) Nucleic Acids Res. 25(17):3389-3402. When utilizing BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., XBLAST and BLAST) can be used (See www.ncbi.nlm.nih.gov).

[0048] Identity: As used herein, the term “identity” refers to the overall relatedness between polymeric molecules, e.g., between nucleic acid molecules (e.g., oligonucleotides, DNA, RNA, etc.) and / or between Page 18 of 20113318736vlAttorney Docket No.: 2010581-1667polypeptide molecules. In some embodiments, polymeric molecules are considered to be “substantially identical” to one another if their sequences are at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% identical. Calculation of the percent identity of two nucleic acid or polypeptide sequences, for example, can be performed by aligning the two sequences for optimal comparison purposes (e.g., gaps can be introduced in one or both of a first and a second sequences for optimal alignment and non-identical sequences can be disregarded for comparison purposes). In certain embodiments, the length of a sequence aligned for comparison purposes is at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or substantially 100% of the length of a reference sequence. The nucleotides at corresponding positions are then compared. When a position in the first sequence is occupied by the same residue (e.g., nucleotide or amino acid) as the corresponding position in the second sequence, then the molecules are identical at that position. The percent identity between the two sequences is a function of the number of identical positions shared by the sequences, taking into account the number of gaps, and the length of each gap, which needs to be introduced for optimal aligmnent of the two sequences. The comparison of sequences and determination of percent identity between two sequences can be accomplished using a mathematical algorithm. For example, the percent identity between two nucleotide sequences can be determined using the algorithm of Meyers and Miller (CABIOS, 1989, 4: 11-17), which has been incorporated into the ALIGN program (version 2.0). In some exemplary embodiments, nucleic acid sequence comparisons made with the ALIGN program use a PAM 120 weight residue table, a gap length penalty of 12 and a gap penalty of 4. The percent identity between two nucleotide sequences can, alternatively, be determined using the GAP program in the GCG software package using an NWSgapdna. CMP matrix.

[0049] Internucleotidic linkage'. As used herein, the phrase “internucleotidic linkage” refers generally to a linkage linking nucleoside units of an oligonucleotide or a nucleic acid. In some embodiments, an internucleotidic linkage is a phosphodi ester linkage, as extensively found in naturally occurring DNA and RNA molecules (natural phosphate linkage (-OP(=O)(OH)O-), which as appreciated by those skilled in the art may exist as a salt form). In some embodiments, an internucleotidic linkage is a modified internucleotidic linkage (not a natural phosphate linkage). In some embodiments, an internucleotidic linkage is a “modified internucleotidic linkage” wherein at least one oxygen atom or -OH of a phosphodiester linkage is replaced by a different organic or inorganic moiety. In some embodiments, such an organic or inorganic moiety is selected from =S, =Se, =NR’, -SR’, -SeR’, -N(R’)?, B(R’), -S-, -Se-, and -N(R’)-, wherein each R’ is independently as defined and described in the present disclosure. In some embodiments, an internucleotidic linkage is a phosphotriester linkage, phosphorothioate linkage (or phosphorothioate diester linkage, -OP(=O)(SH)O-, which as appreciated by those skilled in the art may exist as a salt form), or phosphorothioate triester linkage. In some embodiments, a modified internucleotidic linkage is a phosphorothioate linkage. In some embodiments, an internucleotidic linkage is one of, e.g., PNA (peptide nucleic acid) or PMO (phosphorodiamidate Morpholino oligomer) linkage. In some embodiments, a modified internucleotidic linkage is a non-negatively charged internucleotidic linkage. In some embodiments, a modified Page 19 of 20113318736vlAttorney Docket No.: 2010581-1667internucleotidic linkage is a neutral internucleotidic linkage (e.g., nOOl in certain provided oligonucleotides). It is understood by a person of ordinary skill in the art that an internucleotidic linkage may exist as an anion or cation at a given pH due to the existence of acid or base moieties in the linkage. In some embodiments, a modified internucleotidic linkages is a modified internucleotidic linkages designated as s, si, s2, s3, s4, s5, s6, s7, s8, s9, slO, si 1, sl2, sl3, sl4, sl5, sl6, sl7 and sl8 as described in WO 2017 / 210647.

[0050] In vitro: As used herein, the term “in vitro” refers to events that occur in an artificial environment, e.g., in a test tube or reaction vessel, in cell culture, etc., rather than within an organism (e.g., animal, plant and / or microbe).

[0051] In vivo: As used herein, the term “in vivo” refers to events that occur within an organism (e.g., animal, plant and / or microbe).

[0052] Linkage phosphorus: as defined herein, the phrase “linkage phosphorus” is used to indicate that the particular phosphorus atom being referred to is the phosphorus atom present in the internucleotidic linkage, which phosphorus atom corresponds to the phosphorus atom of a phosphodiester internucleotidic linkage as occurs in naturally occurring DNA and RNA. In some embodiments, a linkage phosphorus atom is in a modified internucleotidic linkage, wherein each oxygen atom of a phosphodiester linkage is optionally and independently replaced by an organic or inorganic moiety. In some embodiments, a linkage phosphorus atom is chiral (e.g., as in phosphorothioate internucleotidic linkages). In some embodiments, a linkage phosphorus atom is achiral (e.g., as in natural phosphate linkages).

[0053] Linker: The terms “linker”, “linking moiety” and the like refer to any chemical moiety which connects one chemical moiety to another. As appreciated by those skilled in the art, a linker can be bivalent or trivalent or more, depending on the number of chemical moieties the linker connects. In some embodiments, a linker is a moiety which connects one oligonucleotide to another oligonucleotide in a multimer. In some embodiments, a linker is a moiety optionally positioned between the terminal nucleoside and the solid support or between the terminal nucleoside and another nucleoside, nucleotide, or nucleic acid. In some embodiments, in an oligonucleotide a linker connects a chemical moiety (e.g., a targeting moiety, a lipid moiety, a carbohydrate moiety, etc.) with an oligonucleotide chain (e.g., through its 5 ’-end, 3 ’-end, nucleobase, sugar, internucleotidic linkage, etc.).

[0054] Modified nucleobase: The terms "modified nucleobase", "modified base" and the like refer to a chemical moiety which is chemically distinct from a nucleobase, but which is capable of performing at least one function of a nucleobase. In some embodiments, a modified nucleobase is a nucleobase which comprises a modification. In some embodiments, a modified nucleobase is capable of at least one function of a nucleobase, e.g., forming a moiety in a polymer capable of base-pairing to a nucleic acid comprising an at least complementary sequence of bases. In some embodiments, a modified nucleobase is substituted A, T, C, G, or U, or a substituted tautomer of A, T, C, G, or U. In some embodiments, a modified nucleobase in the context of oligonucleotides refer to a nucleobase that is not A, T, C, G or U.

[0055] Modified nucleoside: The term "modified nucleoside" refers to a moiety derived from or Page 20 of 20113318736vlAttorney Docket No.: 2010581-1667chemically similar to a natural nucleoside, but which comprises a chemical modification which differentiates it from a natural nucleoside. Non-limiting examples of modified nucleosides include those which comprise a modification at the base and / or the sugar. Non-limiting examples of modified nucleosides include those with a 2’ modification at a sugar. Non-limiting examples of modified nucleosides also include abasic nucleosides (which lack a nucleobase). In some embodiments, a modified nucleoside is capable of at least one function of a nucleoside, e.g., forming a moiety in a polymer capable of base-pairing to a nucleic acid comprising an at least complementary sequence of bases.

[0056] Modified nucleotide'. The term “modified nucleotide” includes any chemical moiety which differs structurally from a natural nucleotide but is capable of performing at least one function of a natural nucleotide. In some embodiments, a modified nucleotide comprises a modification at a sugar, base and / or internucleotidic linkage. In some embodiments, a modified nucleotide comprises a modified sugar, modified nucleobase and / or modified internucleotidic linkage. In some embodiments, a modified nucleotide is capable of at least one function of a nucleotide, e.g., forming a subunit in a polymer capable of base-pairing to a nucleic acid comprising an at least complementary sequence of bases.

[0057] Modified sugar; The term “modified sugar” refers to a moiety that can replace a sugar. A modified sugar mimics the spatial arrangement, electronic properties, or some other physicochemical property of a sugar. In some embodiments, as described in the present disclosure, a modified sugar is substituted ribose or deoxyribose. In some embodiments, a modified sugar comprises a 2’ -modification. Examples of useful 2’-modification are widely utilized in the art and described herein. In some embodiments, a 2’ -modification is 2’-F. In some embodiments, a 2’ -modification is 2’-OR, wherein R is optionally substituted C1-10 aliphatic. In some embodiments, a 2’ -modification is 2’-OMe. In some embodiments, a 2 ’-modification is 2’-MOE. In some embodiments, a modified sugar is a bicyclic sugar (e.g., a sugar used in LNA, BNA, etc.). In some embodiments, in the context of oligonucleotides, a modified sugar is a sugar that is not ribose or deoxyribose as typically found in natural RNA or DNA.

[0058] Nucleic acid; The term “nucleic acid”, as used herein, includes any nucleotides and polymers thereof. The term “polynucleotide”, as used herein, refers to a polymeric form of nucleotides of any length, either ribonucleotides (RNA) or deoxyribonucleotides (DNA) or a combination thereof. These terms refer to the primary structure of the molecules and, thus, include double- and single-stranded DNA, and double- and single-stranded RNA. These terms include, as equivalents, analogs of either RNA or DNA comprising modified nucleotides and / or modified polynucleotides, such as, though not limited to, methylated, protected and / or capped nucleotides or polynucleotides. The terms encompass poly- or oligo-ribonucleotides (RNA) and poly- or oligo-deoxyribonucleotides (DNA); RNA or DNA derived from N-glycosides or C-glycosides of nucleobases and / or modified nucleobases; nucleic acids derived from sugars and / or modified sugars; and nucleic acids derived from phosphate bridges and / or modified internucleotidic linkages. The term encompasses nucleic acids containing any combinations of nucleobases, modified nucleobases, sugars, modified sugars, phosphate bridges or modified internucleotidic linkages. Examples include, and are not Page 21 of 20113318736vlAttorney Docket No.: 2010581-1667limited to, nucleic acids containing ribose moieties, nucleic acids containing deoxy-ribose moieties, nucleic acids containing both ribose and deoxyribose moieties, nucleic acids containing ribose and modified ribose moieties. Unless otherwise specified, the prefix poly- refers to a nucleic acid containing 2 to about 10,000 nucleotide monomer units and wherein the prefix oligo- refers to a nucleic acid containing 2 to about 200 nucleotide monomer units.

[0059] Nucleobase: The term “nucleobase” refers to the parts of nucleic acids that are involved in the hydrogen-bonding that binds one nucleic acid strand to another complementary strand in a sequence specific manner. The most common naturally-occurring nucleobases are adenine (A), guanine (G), uracil (U), cytosine (C), and thymine (T). In some embodiments, a naturally-occurring nucleobases are modified adenine, guanine, uracil, cytosine, or thymine. In some embodiments, a naturally-occurring nucleobases are methylated adenine, guanine, uracil, cytosine, or thymine. In some embodiments, a nucleobase comprises a heteroaryl ring wherein a ring atom is nitrogen, and when in a nucleoside, the nitrogen is bonded to a sugar moiety. In some embodiments, a nucleobase comprises a heterocyclic ring wherein a ring atom is nitrogen, and when in a nucleoside, the nitrogen is bonded to a sugar moiety. In some embodiments, a nucleobase is a “modified nucleobase,” a nucleobase other than adenine (A), guanine (G), uracil (U), cytosine (C), and thymine (T). In some embodiments, a modified nucleobase is substituted A, T, C, G or U. In some embodiments, a modified nucleobase is a substituted tautomer of A, T, C, G, or U. In some embodiments, a modified nucleobases is methylated adenine, guanine, uracil, cytosine, or thymine. In some embodiments, a modified nucleobase mimics the spatial arrangement, electronic properties, or some other physicochemical property of the nucleobase and retains the property of hydrogen-bonding that binds one nucleic acid strand to another in a sequence specific manner. In some embodiments, a modified nucleobase can pair with all of the five naturally occurring bases (uracil, thymine, adenine, cytosine, or guanine) without substantially affecting the melting behavior, recognition by intracellular enzymes or activity of the oligonucleotide duplex. As used herein, the term “nucleobase” also encompasses structural analogs used in lieu of natural or naturally-occurring nucleotides, such as modified nucleobases and nucleobase analogs. In some embodiments, a nucleobase is optionally substituted A, T, C, G, or U, or an optionally substituted tautomer of A, T, C, G, or U. In some embodiments, a “nucleobase” refers to a nucleobase unit in an oligonucleotide or a nucleic acid (e.g., A, T, C, G or U as in an oligonucleotide or a nucleic acid).

[0060] Nucleoside'. The term “nucleoside” refers to a moiety wherein a nucleobase or a modified nucleobase is covalently bound to a sugar or a modified sugar. In some embodiments, a nucleoside is a natural nucleoside, e.g., adenosine, deoxyadenosine, guanosine, deoxyguanosine, thymidine, uridine, cytidine, or deoxycytidine. In some embodiments, a nucleoside is a modified nucleoside, e.g., a substituted natural nucleoside selected from adenosine, deoxyadenosine, guanosine, deoxyguanosine, thymidine, uridine, cytidine, and deoxycytidine. In some embodiments, a nucleoside is a modified nucleoside, e.g., a substituted tautomer of a natural nucleoside selected from adenosine, deoxyadenosine, guanosine, deoxyguanosine, thymidine, uridine, cytidine, and deoxycytidine. In some embodiments, a “nucleoside” refers to a nucleoside Page 22 of 20113318736vlAttorney Docket No.: 2010581-1667unit in an oligonucleotide or a nucleic acid.

[0061] Nucleotide'. The term “nucleotide” as used herein refers to a monomeric unit of a polynucleotide that consists of a nucleobase, a sugar, and one or more internucleotidic linkages (e.g., phosphate linkages in natural DNA and RNA). The naturally occurring bases [guanine, (G), adenine, (A), cytosine, (C), thymine, (T), and uracil (U)] are derivatives of purine or pyrimidine, though it should be understood that naturally and non-naturally occurring base analogs are also included. The naturally occurring sugar is the pentose (five-carbon sugar) deoxyribose (which forms DNA) or ribose (which forms RNA), though it should be understood that naturally and non-naturally occurring sugar analogs are also included. Nucleotides are linked via internucleotidic linkages to form nucleic acids, or polynucleotides. Many internucleotidic linkages are known in the art (such as, though not limited to, phosphate, phosphorothioates, boranophosphates and the like). Artificial nucleic acids include PNAs (peptide nucleic acids), phosphotriesters, phosphorothionates, H-phosphonates, phosphoramidates, boranophosphates, methylphosphonates, phosphonoacetates, thiophosphonoacetates and other variants of the phosphate backbone of native nucleic acids, such as those described herein. In some embodiments, a natural nucleotide comprises a naturally occurring base, sugar and internucleotidic linkage. As used herein, the term “nucleotide” also encompasses structural analogs used in lieu of natural or naturally-occurring nucleotides, such as modified nucleotides and nucleotide analogs. In some embodiments, a “nucleotide” refers to a nucleotide unit in an oligonucleotide or a nucleic acid.

[0062] Oligonucleotide-. The term "oligonucleotide" refers to a polymer or oligomer of nucleotides, and may contain any combination of natural and non-natural nucleobases, sugars, and internucleotidic linkages.

[0063] Oligonucleotides can be single-stranded or double-stranded. A single-stranded oligonucleotide can have double-stranded regions (formed by two portions of the single-stranded oligonucleotide) and a double-stranded oligonucleotide, which comprises two oligonucleotide chains, can have single-stranded regions for example, at regions where the two oligonucleotide chains are not complementary to each other. Example oligonucleotides include, but are not limited to structural genes, genes including control and termination regions, self-replicating systems such as viral or plasmid DNA, single-stranded and doublestranded RNAi agents and other RNA interference reagents (RNAi agents or iRNA agents), shRNA, antisense oligonucleotides, ribozymes, microRNAs, microRNA mimics, supermirs, aptamers, antimirs, antagomirs, U1 adaptors, triplex-forming oligonucleotides, G-quadruplex oligonucleotides. RNA activators, immunostimulatory oligonucleotides, and decoy oligonucleotides.

[0064] Oligonucleotides of the present disclosure can be of various lengths. In particular embodiments, oligonucleotides can range from about 2 to about 200 nucleosides in length. In various related embodiments, oligonucleotides, single-stranded, double-stranded, or triple-stranded, can range in length from about 4 to about 10 nucleosides, from about 10 to about 50 nucleosides, from about 20 to about 50 nucleosides, from about 15 to about 30 nucleosides, from about 20 to about 30 nucleosides in length. In some embodiments, an oligonucleotide is from about 9 to about 39 nucleosides in length. In some embodiments, an oligonucleotide is from about 25 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about Page 23 of 20113318736vlAttorney Docket No.: 2010581-166726 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 27 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 28 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 29 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 30 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 31 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 32 to about 70 nucleosides in length. In some embodiments, an oligonucleotide is from about 25 to about 60 nucleosides in length. In some embodiments, an oligonucleotide is from about 25 to about 50 nucleosides in length. In some embodiments, an oligonucleotide is from about 25 to about 40 nucleosides in length. In some embodiments, an oligonucleotide is from about 30 to about 40 nucleosides in length. In some embodiments, the oligonucleotide is at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 nucleosides in length. In some embodiments, an oligonucleotide is at least 4 nucleosides in length. In some embodiments, an oligonucleotide is at least 5 nucleosides in length. In some embodiments, an oligonucleotide is at least 6 nucleosides in length. In some embodiments, an oligonucleotide is at least 7 nucleosides in length. In some embodiments, an oligonucleotide is at least 8 nucleosides in length. In some embodiments, an oligonucleotide is at least 9 nucleosides in length. In some embodiments, an oligonucleotide is at least 10 nucleosides in length. In some embodiments, an oligonucleotide is at least 11 nucleosides in length. In some embodiments, an oligonucleotide is at least 12 nucleosides in length. In some embodiments, an oligonucleotide is at least 15 nucleosides in length. In some embodiments, an oligonucleotide is at least 15 nucleosides in length. In some embodiments, an oligonucleotide is at least 16 nucleosides in length. In some embodiments, an oligonucleotide is at least 17 nucleosides in length. In some embodiments, an oligonucleotide is at least 18 nucleosides in length. In some embodiments, an oligonucleotide is at least 19 nucleosides in length. In some embodiments, an oligonucleotide is at least 20 nucleosides in length. In some embodiments, an oligonucleotide is at least 25 nucleosides in length. In some embodiments, an oligonucleotide is at least 26 nucleosides in length. In some embodiments, an oligonucleotide is at least 27 nucleosides in length. In some embodiments, an oligonucleotide is at least 28 nucleosides in length. In some embodiments, an oligonucleotide is at least 29 nucleosides in length. In some embodiments, an oligonucleotide is at least 30 nucleosides in length. In some embodiments, an oligonucleotide is at least 31 nucleosides in length. In some embodiments, an oligonucleotide is at least 32 nucleosides in length. In some embodiments, an oligonucleotide is at least 33 nucleosides in length. In some embodiments, an oligonucleotide is at least 34 nucleosides in length. In some embodiments, an oligonucleotide is at least 35 nucleosides in length. In some embodiments, an oligonucleotide is at least 36 nucleosides in length. In some embodiments, an oligonucleotide is at least 37 nucleosides in length. In some embodiments, an oligonucleotide is at least 38 nucleosides in length. In some embodiments, an oligonucleotide is at least 39 nucleosides in length. In some embodiments, an oligonucleotide is at least 40 nucleosides in length. In some embodiments, an oligonucleotide is 25 nucleosides in length. In some embodiments, an oligonucleotide is 26 nucleosides in length. In some embodiments, an oligonucleotide is 27 nucleosides in length. In some embodiments, an oligonucleotide is 28 nucleosides in length. In some Page 24 of 20113318736vlAttorney Docket No.: 2010581-1667embodiments, an oligonucleotide is 29 nucleosides in length. In some embodiments, an oligonucleotide is 30 nucleosides in length. In some embodiments, an oligonucleotide is 31 nucleosides in length. In some embodiments, an oligonucleotide is 32 nucleosides in length. In some embodiments, an oligonucleotide is 33 nucleosides in length. In some embodiments, an oligonucleotide is 34 nucleosides in length. In some embodiments, an oligonucleotide is 35 nucleosides in length. In some embodiments, an oligonucleotide is 36 nucleosides in length. In some embodiments, an oligonucleotide is 37 nucleosides in length. In some embodiments, an oligonucleotide is 38 nucleosides in length. In some embodiments, an oligonucleotide is 39 nucleosides in length. In some embodiments, an oligonucleotide is 40 nucleosides in length. In some embodiments, each nucleoside counted in an oligonucleotide length independently comprises a nucleobase comprising a ring having at least one nitrogen ring atom. In some embodiments, each nucleoside counted in an oligonucleotide length independently comprises A, T, C, G, or U, or optionally substituted A, T, C, G, or U, or an optionally substituted tautomer of A, T, C, G or U.

[0065] Oligonucleotide type'. As used herein, the phrase “oligonucleotide type” is used to define an oligonucleotide that has a particular base sequence, pattern of backbone linkages (i.e., pattern of internucleotidic linkage types, for example, phosphate, phosphorothioate, phosphorothioate triester, etc.), pattern of backbone chiral centers [i.e., pattern of linkage phosphorus stereochemistry (Rp / Sp)], and pattern of backbone phosphorus modifications. In some embodiments, oligonucleotides of a common designated “type” are structurally identical to one another.

[0066] One of skill in the art will appreciate that synthetic methods of the present disclosure provide for a degree of control during the synthesis of an oligonucleotide strand such that each nucleotide unit of the oligonucleotide strand can be designed and / or selected in advance to have a particular stereochemistry at the linkage phosphorus and / or a particular modification at the linkage phosphorus, and / or a particular base, and / or a particular sugar. In some embodiments, an oligonucleotide strand is designed and / or selected in advance to have a particular combination of stereocenters at the linkage phosphorus. In some embodiments, an oligonucleotide strand is designed and / or determined to have a particular combination of modifications at the linkage phosphorus. In some embodiments, an oligonucleotide strand is designed and / or selected to have a particular combination of bases. In some embodiments, an oligonucleotide strand is designed and / or selected to have a particular combination of one or more of the above structural characteristics. In some embodiments, the present disclosure provides compositions comprising or consisting of a plurality of oligonucleotide molecules (e.g., chirally controlled oligonucleotide compositions). In some embodiments, all such molecules are of the same type (i.e., are structurally identical to one another). In some embodiments, however, provided compositions comprise a plurality of oligonucleotides of different types, typically in pre-determined relative amounts.

[0067] Optionally Substituted: As described herein, compounds of the disclosure may contain optionally substituted, substituted and / or unsubstituted moieties. In general, the term “substituted,” means that one or more hydrogens of the designated moiety are independently replaced with a substituent. Unless otherwise Page 25 of 20113318736vlAttorney Docket No.: 2010581-1667indicated, an “optionally substituted” group may independently have a substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with two or more substituents, the substituents may be either the same or different at every position. In some embodiments, an optionally substituted group is unsubstituted. In some embodiments, an optionally substituted group is substituted. Various substituents are described below.

[0068] Monovalent substituents are independendy halogen; -(CH2)o 4R0; -(CH2)o-40R°; -0(CH2)o-4R°, -0-(CH2)O-4C(0)OR°; -(CH2)O-4CH(OR°)2; -(CH2)0-4Ph, which may be substituted with R°; -(CH2)o-40(CH2)o iPh which may be substituted with R°; -CH=CHPh, which may be substituted with R°; -(Cfhlo-40(CH2)O-I -pyridyl which may be substituted with R°; -C=CR°; -NO2; -CN; -N3; -(CH2)o-4N(R°)2; -(CH2)o-4N(R°)C(O)R°; -N(R°)C(S)R°; -(CH2)O-4N(R0)C(0)N(R°)2; -N(RO)C(S)N(R°)2; -(CH2)O-4N(R0)C(0)OR°; -N(R°)N(R°)C(O)R°; -N(R°)N(R°)C(O)N(R°)2; -N(R°)N(R°)C(O)OR0; -(CH2)o4C(O)R°; -C(S)R°; -(CH2)O-4C(0)OR°; -(CH2)O-4C(0)SR°; -(CH2)o-4C(0)OSi(R°)3; -(CH2)o-40C(0)R°; -OC(0)(CH2)o-4SR°, SC(S)SR°; -(CH2)O-4SC(0)R°; -(CH2)O-4C(0)N(R°)2; -C(S)N(RO)2; -C(S)SR°; -SC(S)SR°, -(CH2)O-4OC(O)N(RO)2; -C(O)N(OR°)R°; -C(O)C(O)R°; -C(O)CH2C(O)RO; -C(NOR°)R°; -(CH2)O-4SSR°; -(CH2)O-4S(O)2R°; -(CH2)O-4S(0)2OR0; -(CH2)O-40S(0)2R°; -S(O)2N(RO)2; -(CH2)O-4S(0)R°; -N(RO)S(O)2N(R°)2; -N(R°)S(O)2R°; -N(OR°)R°; -C(NH)N(RO)2; -Si(R°)3; -OSi(R°)3; -P(R°)2; -P(OR°)2; -OP(R°)2; -OP(OR°)2; -N(RO)P(R°)2; -B(RO)2; -OB(RO)2; -P(O)(RO)2; -OP(O)(RO)2; -N(R°)P(O)(RO)2; -(CI-4 straight or branched alkylene)O-N(R°)2; or -(C1.4 straight or branched alkylene)C(O)O-N(R°)2; wherein each R° may be independently substituted as defined below and is independently hydrogen, CMO (e.g., Ci-e, C1-4, etc.) aliphatic, C1-10 (e.g., Ci-e, C1.4, etc.) heteroaliphatic having 1-5 heteroatoms independently selected from nitrogen, oxygen, sulfur, silicon and phosphorus, Ce-io (e.g., Ce, C10, etc.) aryl, 5-10 (e.g., 5-9, 5-6, 5, 6, 9, 10, etc.) membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen and sulfur, -CH2-(C6-IO (e.g., Ce, C10, etc.) aryl), -0(CH2)o-i(Ce-io (e.g., Ce, C10, etc.) aryl), -CH2-(5-10 (e.g., 5-9, 5-6, 5, 6, 9, 10, etc.) membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen and sulfur), -0(CH2)o-i(5-10 (e.g., 5-9, 5-6, 5, 6, 9, 10, etc.) membered heteroaryl having 1-4 heteroatoms independently selected from nitrogen, oxygen and sulfur), a 3-10 (e.g., 3-6, 5-6, 3, 4, 5, 6, 7, 8, 9, 10, etc.) membered, monocyclic, bicyclic, or polycyclic, saturated, or partially unsaturated ring having 0-5 heteroatoms independently selected from nitrogen, oxygen, sulfur, silicon and phosphorus, or, notwithstanding the definition above, two independent occurrences of R°, taken together with their intervening atom(s), form a 3-10 (e.g., 3-6, 5-6, 3, 4, 5, 6, 7, 8, 9, 10, etc.) membered, monocyclic, bicyclic, or polycyclic, saturated, partially unsaturated or aromatic ring (for aromatic ring, 5-10 (e.g., 5-9, 5-6, 5, 6, 9, 10, etc.) membered) having, in addition to the intervening atom(s), 0-5 heteroatoms independendy selected from nitrogen, oxygen, sulfur, silicon and phosphorus, which may be substituted as defined below.

[0069] Monovalent substituents on R° (or the ring formed by taking two independent occurrences of R° together with their intervening atoms), are independently halogen, -(CH2)0-2R*, -(haloR*), -(CH2)o-20H, - Page 26 of 20113318736vlAttorney Docket No.: 2010581-1667(CH2)0-2OR*, (CH2)0-2CH(OR*)2; -O(haloR’), -CN, -N3, -(CH2)o-2C(0)R*, -(CH2)o-2C(0)OH, -(CH2)o-2C(O)OR*, -(CH2)0-2SR*. -(CH2)0-2SH, -(CH2)0-2NH2, -(CH2)0-2NHR*, -(CH2)0-2NR*2, -NO2, -SiR*3, -OSiR*3, -C(O)SR* -(C1-4 straight or branched al kylene)C(O)OR*, or -SSR* wherein each R* is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently selected from C1-4 aliphatic, -CH2Ph, -0(CH2)o iPh, or a 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur. Divalent substituents on a saturated carbon atom of R° are independently =0 or =S.

[0070] Divalent substituents are independently the following: =0, =S, =NNR*2, =NNHC(O)R*, =NNHC(O)OR*, =NNHS(O)2R*, =NR*, =N0R*, -O(C(R*2))2-3O-, or -S(C(R*2))2-3S- wherein each independent occurrence of R* is selected from hydrogen, Ci-6 aliphatic which may be substituted as defined below, or an unsubstituted 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur. Divalent substituents that are bound to vicinal substitutable carbons of an “optional ly substituted” group are independently -O(CR*2)2-3O-, wherein each independent occurrence of R* is selected from hydrogen, C1-6 aliphatic which may be substituted as defined below, or an unsubstituted 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur. In some embodiments, a bivalent substituent is =N. In some embodiments, it is =CR* wherein R* is as described herein.

[0071] Substituents on the aliphatic group of R* are independently halogen, -R*. -(haloR*), -OH, -OR*. -O(haloR*), -CN, -C(O)OH, -C(O)OR*, -NH2, -NHR*, -NR*2, or -NO2, wherein each R* is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C1-4 aliphatic, -CH2Ph, -0(CH2)o iPh, or a 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur.

[0072] Substituents on a substitutable nitrogen are independently -Rt, -NRt2, -C(O)Rt, -C(O)ORt, -C(O)C(O)Rt, -C(O)CH2C(O)Rt, -S(O)2Rf, -S(O)2NRt2, -C(S)NRf2, -C(NH)NRt2, or -N(R+)S(O)2Rt; wherein each Rfis independently hydrogen, C1-6 aliphatic which may be substituted as defined below, unsubstituted -OPh, or an unsubstituted 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or, notwithstanding the definition above, two independent occurrences of Rf, taken together with their intervening atom(s) form an unsubstituted 3-12 (e.g., 3-10, 3-6, 5-10, 5-6, 3, 4, 5, 6, 7, 8, 9, 10, etc.) membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur.

[0073] Substituents on the aliphatic group of R’ are independently halogen, -R*, -(haloR*), -OH, -OR*,Page 27 of 20113318736vlAttorney Docket No.: 2010581-1667-O(haloR*), -CN, -C(O)OH, C(O)OR*, -NH2, -NHR*, -NR*2, or -NO2, wherein each R* is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C1-4 aliphatic, -CH2Ph. -0(CH2)o iPh, or a 3-6 (e.g., 3-5, 5-6, etc.)-membered saturated, partially unsaturated, or aromatic ring (for aromatic ring, 5- or 6-membered) having 0-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur.

[0074] Partially unsaturated'. As used herein, the term “partially unsaturated” refers to a ring moiety that includes at least one double or triple bond. The term “partially unsaturated” is intended to encompass rings having multiple sites of unsaturation, but is not intended to include aryl or heteroaryl moieties, as herein defined.

[0075] Pharmaceutical composition'. As used herein, the term “pharmaceutical composition” refers to an active agent, formulated together with one or more pharmaceutically acceptable carriers. In some embodiments, an active agent is present in unit dose amount appropriate for administration in a therapeutic regimen that shows a statistically significant probability of achieving a predetermined therapeutic effect when administered to a relevant population. In some embodiments, pharmaceutical compositions may be specially formulated for administration in solid or liquid form, including those adapted for the following: oral administration, for example, drenches (aqueous or non-aqueous solutions or suspensions), tablets, e.g., those targeted for buccal, sublingual, and systemic absorption, boluses, powders, granules, pastes for application to the tongue; parenteral administration, for example, by subcutaneous, intramuscular, intravenous or epidural injection as, for example, a sterile solution or suspension, or sustained-release formulation; topical application, for example, as a cream, ointment, or a controlled-release patch or spray applied to the skin, lungs, or oral cavity; intravaginally or intrarectally, for example, as a pessary, cream, or foam; sublingually; ocularly; transdermally; or nasally, pulmonary, and to other mucosal surfaces.

[0076] Pharmaceutically acceptable.'. As used herein, the phrase “pharmaceutically acceptable” refers to those compounds, materials, compositions and / or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit / risk ratio.

[0077] Pharmaceutically acceptable carrier: As used herein, the term “pharmaceutically acceptable carrier” means a pharmaceutically-acceptable material, composition or vehicle, such as a liquid or solid filler, diluent, excipient, or solvent encapsulating material, involved in carrying or transporting the subject compound from one organ, or portion of the body, to another organ, or portion of the body. Each carrier must be “acceptable” in the sense of being compatible with the other ingredients of the formulation and not injurious to the patient. Some examples of materials which can serve as pharmaceutically-acceptable carriers include: sugars, such as lactose, glucose and sucrose; starches, such as corn starch and potato starch; cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients, such as cocoa butter and suppository waxes; oils, such as peanut oil,Page 28 of 20113318736vlAttorney Docket No.: 2010581-1667cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols, such as propylene glycol; polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; esters, such as ethyl oleate and ethyl laurate; agar; buffering agents, such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer’s solution; ethyl alcohol; pH buffered solutions; polyesters, polycarbonates and / or polyanhydrides; and other non-toxic compatible substances employed in pharmaceutical formulations.

[0078] Pharmaceutically acceptable salt: The term “pharmaceutically acceptable salt”, as used herein, refers to salts of such compounds that are appropriate for use in pharmaceutical contexts, i.e., salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit / risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, S. M. Berge, et al. describes pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 66: 1-19 (1977). In some embodiments, pharmaceutically acceptable salt include, but are not limited to, nontoxic acid addition salts, which are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. In some embodiments, pharmaceutically acceptable salts include, but are not limited to, adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3 -phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like. In some embodiments, a provided compound comprises one or more acidic groups, e.g., an oligonucleotide, and a pharmaceutically acceptable salt is an alkali, alkaline earth metal, or ammonium (e.g., an ammonium salt of N(R)3, wherein each R is independently defined and described in the present disclosure) salt. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. In some embodiments, a pharmaceutically acceptable salt is a sodium salt. In some embodiments, a pharmaceutically acceptable salt is a potassium salt. In some embodiments, a pharmaceutically acceptable salt is a calcium salt. In some embodiments, pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, alkyl having from 1 to 6 carbon atoms, sulfonate and aryl sulfonate. In some embodiments, a provided compound comprises more than one acid groups, for example, an oligonucleotide may comprise two or more acidic groups (e.g., in natural phosphate linkages and / or modified internucleotidic linkages). In some embodiments, a pharmaceutically acceptable salt, or generally a salt, of such a compound comprises two or more cations, which can be the same or different. In some embodiments, in a pharmaceutically acceptable Page 29 of 20113318736vlAttorney Docket No.: 2010581-1667salt (or generally, a salt), all ionizable hydrogen (e.g., in an aqueous solution with a pKa no more than about 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2; in some embodiments, no more than about 7; in some embodiments, no more than about 6; in some embodiments, no more than about 5; in some embodiments, no more than about 4; in some embodiments, no more than about 3) in the acidic groups are replaced with cations. In some embodiments, each phosphorothioate and phosphate group independently exists in its salt form (e.g., if sodium salt, -O-P(O)(SNa)-O- and -O-P(O)(ONa)-O-, respectively). In some embodiments, each phosphorothioate and phosphate internucleotidic linkage independently exists in its salt form (e.g., if sodium salt, -O-P(O)(SNa)-O- and -O-P(O)(ONa)-O-, respectively). In some embodiments, a pharmaceutically acceptable salt is a sodium salt of an oligonucleotide. In some embodiments, a pharmaceutically acceptable salt is a sodium salt of an oligonucleotide, wherein each acidic phosphate and modified phosphate group (e.g., phosphorothioate, phosphate, etc.), if any, exists as a salt form (all sodium salt).

[0079] Protecting group: The term “protecting group,” as used herein, is well known in the art and includes those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rdedition, John Wiley & Sons, 1999, the entirety of which is incorporated herein by reference. Also included are those protecting groups specially adapted for nucleoside and nucleotide chemistry described in Current Protocols in Nucleic Acid Chemistry, edited by Serge L. Beaucage et al. 06 / 2012, the entirety of Chapter 2 is incorporated herein by reference. Suitable amino-protecting groups include methyl carbamate, ethyl carbamate, 9-fluorenylmethyl carbamate (Fmoc), 9-(2-sulfo)fluorenylmethyl carbamate, 9-(2,7-dibromo)fluoroenylmethyl carbamate, 2,7-di-t-butyl-[9-( 10,10-dioxo-l 0, 10,10,10-tetrahydrothioxanthyl)]methyl carbamate (DBD-Tmoc), 4-methoxyphenacyl carbamate (Phenoc), 2,2,2-trichloroethyl carbamate (Troc), 2-trimethylsilylethyl carbamate (Teoc), 2-phenylethyl carbamate (hZ), 1-(1-adamantyl)-l-methylethyl carbamate (Adpoc), l,l-dimethyl-2-haloethyl carbamate, l,l-dimethyl-2,2-dibromoethyl carbamate (DB-t-BOC), l,l-dimethyl-2,2,2-trichloroethy] carbamate (TCBOC), 1-methyl-l-(4-biphenylyl)ethyl carbamate (Bpoc), l-(3,5-di-t-butylphenyl)-l-methylethyl carbamate (t-Bumeoc), 2-(2’- and 4’-pyridyl)ethyl carbamate (Pyoc), 2-(N, N-dicyclohexylcarboxamido)ethyl carbamate, t-butyl carbamate (BOC), 1-adamantyl carbamate (Adoc), vinyl carbamate (Voc), allyl carbamate (Alloc), 1-isopropylallyl carbamate (Ipaoc), cinnamyl carbamate (Coc), 4-nitrocinnamyl carbamate (Noc), 8-quinolyl carbamate, N-hydroxypiperidinyl carbamate, alkyldithio carbamate, benzyl carbamate (Cbz), p-methoxybenzyl carbamate (Moz), p-nitobenzyl carbamate, p-bromobenzyl carbamate, p-chlorobenzyl carbamate, 2,4-dichlorobenzyl carbamate, 4-methylsulfinylbenzyl carbamate (Msz), 9-anthrylmethyl carbamate, diphenylmethyl carbamate, 2-methylthioethyl carbamate, 2-methylsulfonylethyl carbamate, 2-(p-toluenesulfonyl)ethyl carbamate, [2-(l,3-dithianyl)]methyl carbamate (Dmoc), 4-methyl thiophenyl carbamate (Mtpc), 2,4-dimethylthiophenyl carbamate (Bmpc), 2-phosphonioethyl carbamate (Peoc), 2-triphenylphosphonioisopropyl carbamate (Ppoc), l,l-dimethyl-2-cyanoethyl carbamate, m-chloro-p-acyloxybenzyl carbamate, p-(dihydroxyboryl)benzyl carbamate, 5-benzisoxazolylmethyl carbamate, 2-(trifluoromethyl)-6-chromonylmethyl carbamate (Tcroc), m-nitrophenyl carbamate, 3,5-dimethoxybenzyl Page 30 of 20113318736vlAttorney Docket No.: 2010581-1667carbamate, o-nitrobenzyl carbamate, 3,4 dimethoxy 6 nitrobenzyl carbamate, phenyl(o-nitrophenyl)methyl carbamate, phenothiazinyl-(10)-carbonyl derivative, N’-p-toluenesulfonylaminocarbonyl derivative, N’-phenylaminothiocarbonyl derivative, t-amyl carbamate, S-benzyl thiocarbamate, p-cyanobenzyl carbamate, cyclobutyl carbamate, cyclohexyl carbamate, cyclopentyl carbamate, cyclopropylmethyl carbamate, p-decyloxybenzyl carbamate, 2,2-dimethoxycarbonylvinyl carbamate, o-(N, N-dimethylcarboxamido)benzyl carbamate, l,l-dimethyl-3-(N, N-dimethylcarboxamido)propyl carbamate, 1,1-dimethylpropynyl carbamate, di(2-pyridyl)methyl carbamate, 2-furanylmethyl carbamate, 2-iodoethyl carbamate, isoborynl carbamate, isobutyl carbamate, isonicotinyl carbamate, p-(p’-methoxyphenylazo)benzyl carbamate, 1 -methylcyclobutyl carbamate, 1-methylcyclohexyl carbamate, 1 -methyl- 1-cyclopropylmethyl carbamate, l-methyl-l-(3,5-dimethoxyphenyDethyl carbamate, l-methyl-l-(p-phenylazophenyl)ethyl carbamate, 1-methyl-l-phenylethyl carbamate, l-methyl-l-(4-pyridyl)ethyl carbamate, phenyl carbamate, p-(phenylazo)benzyl carbamate, 2,4,6-tri-t-butylphenyl carbamate, 4-(trimethylammonium)benzyl carbamate, 2,4,6-trimethylbenzyl carbamate, formamide, acetamide, chloroacetamide, trichloroacetamide, trifluoroacetamide, phenylacetamide, 3-phenylpropanamide, picolinamide. 3-pyridylcarboxamide, N-benzoylphenylalanyl derivative, benzamide, p-phenylbenzamide, o-nitophenylacetamide, o-nitrophenoxyacetamide, acetoacetamide, (N’-dithiobenzyloxycarbonylamino)acetamide, 3-(p-hydroxyphenyl)propanamide, 3-(o-nitrophenyl)propanamide, 2-methyl-2-(o-nitrophenoxy)propanamide, 2-methyl-2-(o-phenylazophenoxy)propanamide, 4-chlorobutanamide, 3-methyl-3-nitrobutanamide, o-nitrocinnamide, N-acetylmethionine derivative, o-nitrobenzamide, o-(benzoyloxymethyl)benzamide, 4,5-diphenyl-3-oxazolin-2-one, N-phthalimide, N-dithiasuccinimide (Dts), N-2,3-diphenylmaleimide, N-2,5-dimethylpyrrole, N-1,1,4,4-tetramethyldisilylazacyclopentane adduct (STABASE), 5-substituted 1,3-dimethyl- 1,3,5— triazacyclohexan-2-one, 5-substituted l,3-dibenzyl-l,3,5-triazacyclohexan-2-one, 1-substituted 3,5-dinitro^l- pyridone, N-methylamine, N-allylamine, N-[2-(trimethylsi]y])ethoxy]methylamine (SEM), N-3-acetoxypropylamine, N-(l-isopropyl^l-nitro-2-oxo-3-pyroolin-3-yl)amine, quaternary ammonium salts, N-benzylamine, N-di(4— methoxyphenyl)methylamine, N-5-dibenzosuberylamine, N-triphenylmethylamine (Tr), N-[(4-methoxyphenyl)diphenylmethyl]amine (MMTr), N-9-phenylfluorenylamine (PhF), N-2,7-dichloro-9-fluorenylmethyleneamine, N-ferrocenylmethylamino (Fem), N-2-picolylamino N’-oxide, N-1,1-dimethylthiomethyleneamine, N-benzylideneamine, N-p-methoxybenzylideneamine, N-diphenylmethyleneamine, N-[(2-pyridyl)mesityl]methyleneamine, N-(N’, N’-dimethylaminomethylene)amine, N, N’-isopropylidenediamine, N-p-nitrobenzylideneamine, N-salicylideneamine, N-5-chlorosalicylideneamine, N-(5-chloro-2-hydroxyphenyl)phenylmethyleneamine, N-cyclohexylideneamine, N-(5,5-dimetliyl-3-oxo-l-cyclohexenyl)amine, N-borane derivative, N-diphenylborinic acid derivative, N-[phenyl(pentacarbonylchromium- or tungsten)carbonyl]amine, N-copper chelate, N-zinc chelate, N-nitroamine, N-nitrosoamine, amine N-oxide, diphenylphosphinamide (Dpp), dimethylthiophosphinamide (Mpt), diphenylthiophosphinamide (Ppt), dialkyl phosphoramidates, dibenzyl phosphoramidate, diphenyl phosphoramidate, benzenesulfenamide, o-nitrobenzenesulfenamide (Nps), 2,4- Page 31 of 20113318736vlAttorney Docket No.: 2010581-1667dinitrobenzenesulfenamide, pentachlorobenzenesulfenamide, 2 nitro 4 metlioxybenzenesulfenamide, triphenylmethylsulfenamide, 3-nitropyridinesulfenamide (Npys), p-toluenesulfonamide (Ts), benzenesulfonamide, 2, 3, 6, -trimethyl^l— methoxybenzenesulfonamide (Mtr), 2,4,6-trimethoxybenzenesulfonamide (Mtb), 2, 6-di methyl^— methoxybenzenesulfonamide (Pme), 2, 3,5,6-tetramethyl^l-methoxybenzenesulfonamide (Mte), 4-methoxybenzenesulfonamide (Mbs), 2,4,6-trimethylbenzenesulfonamide (Mts), 2,6-dimethoxy^l-methylbenzenesulfonamide (iMds), 2, 2, 5,7,8-pentamethylchroman-6-sulfonamide (Pmc), methanesulfonamide (Ms), P-trimethylsilylethanesulfonamide (SES), 9-anthracenesulfonamide, 4-(4’,8’-dimethoxynaphthyhnethyl)benzenesulfonamide (DNMBS), benzylsulfonamide, trifluoromethylsulfonamide, and phenacylsulfonamide.

[0080] Suitably protected carboxylic acids further include, but are not limited to, silyl-, alkyl-, alkenyl-, aryl-, and arylalkyl-protected carboxylic acids. Examples of suitable silyl groups include trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, t-butyldiphenylsilyl, triisopropylsilyl, and the like. Examples of suitable alkyl groups include methyl, benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, trityl, t-butyl, tetrahydropyran-2-yl. Examples of suitable alkenyl groups include allyl. Examples of suitable aryl groups include optionally substituted phenyl, biphenyl, or naphthyl. Examples of suitable arylalkyl groups include optionally substituted benzyl (e.g., p-methoxybenzyl (MPM), 3,4-dimethoxybenzyl, O-nitrobenzyl, p-nitrobenzyl, p-halobenzyl, 2,6-dichlorobenzyl, p-cyanobenzyl), and 2- and 4— picolyl.

[0081] Suitable hydroxyl protecting groups include methyl, methoxylmethyl (MOM), methylthiomethyl (MTM), t-butylthiomethyl, (phenyldimethylsilyl)methoxymethyl (SMOM), benzyloxymethyl (BOM), p-methoxybenzyloxymethyl (PMBM), (4— methoxyphenoxy)methyl (p-AOM), guaiacolmethyl (GUM), t-butoxymethyl, 4-pentenyloxymethyl (POM), siloxymethyl, 2-methoxyethoxymethyl (MEM), 2,2,2-trichloroethoxymethyl, bis(2-chloroethoxy)methyl, 2-(trimethylsilyl)ethoxymethyl (SEMOR), tetrahydropyranyl (THP), 3-bromotetrahydropyranyl, tetrahydrothiopyranyl, 1-methoxycyclohexyl, 4-methoxytetrahydropyranyl (MTHP), 4-methoxy tetrahydrothiopyranyl, 4-methoxytetrahydrothiopyranyl S, S-dioxide, l-[(2-chloro^l-methyl)phenyl]^l— methoxypiperidin-4-yl (CTMP), l,4-dioxan-2-yl, tetrahydrofuranyl, tetrahydrothiofuranyl, 2,3,3a,4,5,6,7,7a-octahydro-7,8,8-trimethyM-,7-methanobenzofuran-2-yl, 1 -ethoxy ethyl, l-(2-chloroethoxy)ethyl, 1 -methyl- 1 -methoxy ethyl, 1-methyl-l-benzyloxy ethyl, 1 -methyl- l-benzyloxy-2-fluoroethyl, 2,2,2-trichloroethyl, 2-trimethylsilylethyl, 2-(phenylselenyl)ethyl, t-butyl, allyl, p-chlorophenyl, p-methoxyphenyl, 2,4-dinitrophenyl, benzyl, p-methoxybenzyl, 3,4-dimethoxybenzyl, o-nitrobenzyl, p-nitrobenzyl, p-halobenzyl, 2,6-dichlorobenzyl, p-cyanobenzyl, p-phenylbenzyl, 2-picolyl, 4-picolyl, 3-methyl-2-picolyl N-oxido, diphenylmethyl, p,p’-dinitrobenzhydryl, 5-dibenzosuberyl, triphenylmethyl, a-naphthy Idipheny line thy 1, p-methoxyphenyldiphenyhnethyl, di(p-methoxyphenyl)phenylmethyl, tri(p-methoxyphenyl)methyl, 4-(4’-bromophenacyloxyphenyl)diphenylmethyl, 4,4’,4’ ’-tris(4,5-dichlorophthalimidophenyl)methyl, 4,4’,4”-tris(levulinoyloxyphenyl)methyl, 4,4’,4’ ’-tris(benzoyloxyphenyl)methyl, 3-(imidazol-l-yl)bis(4’,4’ ’-dimethoxyphenyl)methyl, 1, l-bis(4-methoxyphenyl)-l ’-pyrenylmethyl, 9-anthryl, 9-(9-phenyl)xanthenyl,Page 32 of 20113318736vlAttorney Docket No.: 2010581-16679-(9-phenyl-10-oxo)anthryl, l,3-benzodithiolan-2-yl, benzisothiazolyl S, S-dioxido, trimethylsilyl (TMS), triethylsilyl (TES), triisopropylsilyl (TIPS), dimethylisopropylsilyl (IPDMS), diethylisopropylsilyl (DEIPS), dimethylthexylsilyl, t-butyldimethylsilyl (TBDMS), t-butyldiphenylsilyl (TBDPS), tribenzylsilyl, tri— p— xylylsilyl, triphenylsilyl, diphenylmethylsilyl (DPMS), t-butylmethoxyphenylsilyl (TBMPS), formate, benzoylformate, acetate, chloroacetate, dichloroacetate, trichloroacetate, trifluoroacetate, methoxyacetate, triphenylmethoxyacetate, phenoxyacetate, p-chlorophenoxyacetate, 3-phenylpropionate, 4-oxopentanoate (levulinate), 4,4-(ethylenedithio)pentanoate (levulinoyldithioacetal), pivaloate, adamantoate, crotonate, 4— methoxycrotonate, benzoate, p-phenylbenzoate, 2,4,6-trimethylbenzoate (mesitoate), alkyl methyl carbonate, 9-fluorenylmethyl carbonate (Fmoc), alkyl ethyl carbonate, alkyl 2,2,2-trichloroethyl carbonate (Troc), 2-(trimethylsilyl)ethyl carbonate (TMSEC), 2-(phenylsulfonyl) ethyl carbonate (Psec), 2-(triphenylphosphonio) ethyl carbonate (Peoc), alkyl isobutyl carbonate, alkyl vinyl carbonate alkyl allyl carbonate, alkyl p-nitrophenyl carbonate, alkyl benzyl carbonate, alkyl p-methoxybenzyl carbonate, alkyl 3,4-dimethoxybenzyl carbonate, alkyl o-nitrobenzyl carbonate, alkyl p-nitrobenzyl carbonate, alkyl S-benzyl thiocarbonate, 4— ethoxy- 1-napththyl carbonate, methyl dithiocarbonate, 2-iodobenzoate, 4-azidobutyrate, 4-nitro-4-methylpentanoate, o-(dibromomethyl)benzoate, 2-formylbenzenesulfonate, 2-(methylthiomethoxy)ethyl, 4— (methylthiomethoxy)butyrate, 2-(methylthiomethoxymethyl)benzoate, 2,6-dichloro-4— methylphenoxyacetate, 2,6-dichloro^l-( 1, 1,3,3-tetramethylbutyl)phenoxyacetate, 2,4- bi s( 1,1-dimethylpropyl)phenoxyacetate, chlorodiphenylacetate, isobutyrate, monosuccinoate, (E)-2-methyl-2-butenoate, o-(methoxycarbonyl)benzoate, a-naphthoate, nitrate, alkyl N, N, N’, N’-tetramethylphosphorodiamidate, alkyl N-phenylcarbamate, borate, dimethylphosphinothioyl, alkyl 2,4— dinitrophenylsulfenate, sulfate, methanesulfonate (mesylate), benzylsulfonate, and tosylate (Ts). For protecting 1,2- or 1,3-diols, the protecting groups include methylene acetal, ethylidene acetal, 1-t-butylethylidene ketal, 1-phenylethylidene ketal, (4-methoxyphenyl)ethylidene acetal, 2,2,2-trichloroethylidene acetal, acetonide, cyclopentylidene ketal, cyclohexylidene ketal, cycloheptylidene ketal, benzylidene acetal, p-methoxybenzylidene acetal, 2,4-dimethoxybenzylidene ketal, 3,4-dimethoxybenzylidene acetal, 2-nitrobenzylidene acetal, methoxymethylene acetal, ethoxymethylene acetal, dimethoxymethylene ortho ester, 1-methoxyethylidene ortho ester, 1 -ethoxy ethylidine ortho ester, 1,2-dimethoxyethylidene ortho ester, a-methoxybenzylidene ortho ester, l-(N, N-dimethylamino)ethylidene derivative, a-(N, N’-dimethylamino)benzylidene derivative, 2-oxacyclopentylidene ortho ester, di— t— butylsilylene group (DTBS), l,3-(l,l,3,3-tetraisopropyldisiloxanylidene) derivative (TIPDS), tetra-t-butoxydisiloxane-l,3-diylidene derivative (TBDS), cyclic carbonates, cyclic boronates, ethyl boronate, and phenyl boronate.

[0082] In some embodiments, a hydroxyl protecting group is acetyl, t-butyl, tbutoxymethyl, methoxy methyl, tetrahydropyranyl, 1 -ethoxyethyl, 1 -(2-chloroethoxy)ethyl, 2- trimethylsilylethyl, p-chlorophenyl, 2,4-dinitrophenyl, benzyl, benzoyl, p-phenylbenzoyl, 2,6- dichlorobenzyl, diphenylmethyl, p-nitrobenzyl, triphenylmethyl (trityl), 4,4'-dimethoxytrityl, trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, t- Page 33 of 20113318736vlAttorney Docket No.: 2010581-1667butyldiphenylsilyl, triphenylsilyl, triisopropylsilyl, benzoylformate, chloroacetyl, trichloroacetyl, trifiuoroacetyl, pivaloyl, 9- fluorenylmethyl carbonate, mesylate, tosylate, triflate, trityl, monomethoxytrityl (MMTr), 4,4'-dimethoxytrityl, (DMTr) and 4,4',4"-trimethoxytrityl (TMTr), 2-cyanoethyl (CE or Cne), 2-(trimethylsilyl)ethyl (TSE), 2-(2-nitrophenyl)ethyl, 2-(4-cyanophenyl)ethyl 2-(4-nitrophenyl)ethyl (NPE), 2-(4-nitrophenylsulfonyl)ethyl, 3,5-dichlorophenyl, 2,4-dimethylphenyl, 2-nitrophenyl, 4-nitrophenyl, 2,4,6-trimethylphenyl, 2-(2-nitrophenyl)ethyl, butylthiocarbonyl, 4,4',4"-tris(benzoyloxy)trityl, diphenylcarbamoyl, levulinyl, 2-(dibromomethyl)benzoyl (Dbmb), 2-(isopropylthiomethoxymethyl)benzoyl (Ptmt), 9-phenylxanthen-9-yl (pixyl) or 9-(p-methoxyphenyl)xanthine-9-yl (MOX). In some embodiments, each of the hydroxyl protecting groups is, independently selected from acetyl, benzyl, t- butyldimethylsilyl, t-butyldiphenylsilyl and 4,4'-dimethoxytrityL In some embodiments, the hydroxyl protecting group is selected from the group consisting of trityl, monomethoxytrityl and 4,4'-dimethoxyfrityl group. In some embodiments, a phosphorous linkage protecting group is a group attached to the phosphorous linkage (e.g., an internucleotidic linkage) throughout oligonucleotide synthesis. In some embodiments, a protecting group is attached to a sulfur atom of an phosphorothioate group. In some embodiments, a protecting group is attached to an oxygen atom of an internucleotide phosphorothioate linkage. In some embodiments, a protecting group is attached to an oxygen atom of the internucleotide phosphate linkage. In some embodiments a protecting group is 2-cyanoethyl (CE or Cne), 2-trimethylsilylethyl, 2-nitroethyl, 2-sulfonylethyl, methyl, benzyl, o-nitrobenzyl, 2-(p-nifrophenyl)ethyl (NPE or Npe), 2-phenylethyl, 3-(N-tert-butylcarboxamido)-l -propyl, 4-oxopentyl, 4-methylthio-l-butyl, 2-cyano- 1,1 -dimethylethyl, 4-N-methylaminobutyl, 3-(2-pyridyl)-l -propyl, 2-[N-methyl-N-(2-pyridyl)]aminoethyl, 2-(N-formyl, N-methyl)aminoethyl, or 4-[N-methyl-N-(2,2,2-trifluoroacetyl)amino]butyl.

[0083] Subject: As used herein, the term “subject” or “test subject” refers to any organism to which a compound (e.g., an oligonucleotide) or composition is administered in accordance with the present disclosure e.g., for experimental, diagnostic, prophylactic and / or therapeutic purposes. Typical subjects include animals (e.g., mammals such as mice, rats, rabbits, non-human primates, and humans; insects; worms; etc.) and plants. In some embodiments, a subject is a human. In some embodiments, a subject may be suffering from and / or susceptible to a disease, disorder and / or condition.

[0084] Substantially: As used herein, the term “substantially” refers to the qualitative condition of exhibiting total or near-total extent or degree of a characteristic or property of interest. A base sequence which is substantially identical or complementary to a second sequence is not fully identical or complementary to the second sequence, but is mostly or nearly identical or complementary to the second sequence. In some embodiments, an oligonucleotide with a substantially complementary sequence to another oligonucleotide or nucleic acid forms duplex with the oligonucleotide or nucleic acid in a similar fashion as an oligonucleotide with a fully complementary sequence. In addition, one of ordinary skill in the biological and / or chemical arts will understand that biological and chemical phenomena rarely, if ever, go to completion and / or proceed to completeness or achieve or avoid an absolute result. The term “substantially” is therefore used herein to Page 34 of 20113318736vlAttorney Docket No.: 2010581-1667capture the potential lack of completeness inherent in many biological and / or chemical phenomena.

[0085] Sugar. The term “sugar” refers to a monosaccharide or polysaccharide in closed and / or open form. In some embodiments, sugars are monosaccharides. In some embodiments, sugars are polysaccharides. Sugars include, but are not limited to, ribose, deoxyribose, pentofuranose, pentopyranose, and hexopyranose moieties. As used herein, the term “sugar” also encompasses structural analogs used in lieu of conventional sugar molecules, such as glycol, polymer of which forms the backbone of the nucleic acid analog, glycol nucleic acid (“GNA”), etc. As used herein, the term “sugar” also encompasses structural analogs used in lieu of natural or naturally-occurring nucleotides, such as modified sugars and nucleotide sugars. In some embodiments, a sugar is a RNA or DNA sugar (ribose or deoxyribose). In some embodiments, a sugar is a modified ribose or deoxyribose sugar, e.g., 2’-modified, 5’-modified, etc. As described herein, in some embodiments, when used in oligonucleotides and / or nucleic acids, modified sugars may provide one or more desired properties, activities, etc. In some embodiments, a sugar is optionally substituted ribose or deoxyribose. In some embodiments, a “sugar” refers to a sugar unit in an oligonucleotide or a nucleic acid.

[0086] Susceptible to: An individual who is “susceptible to” a disease, disorder and / or condition is one who has a higher risk of developing the disease, disorder and / or condition than does a member of the general public. In some embodiments, an individual who is susceptible to a disease, disorder and / or condition is predisposed to have that disease, disorder and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder and / or condition may not have been diagnosed with the disease, disorder and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder and / or condition may exhibit symptoms of the disease, disorder and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder and / or condition may not exhibit symptoms of the disease, disorder and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder, and / or condition will develop the disease, disorder, and / or condition. In some embodiments, an individual who is susceptible to a disease, disorder, and / or condition will not develop the disease, disorder, and / or condition.

[0087] Therapeutic agent: As used herein, the term “therapeutic agent” in general refers to any agent that elicits a desired effect (e.g., a desired biological, clinical, or pharmacological effect) when administered to a subject. In some embodiments, an agent is considered to be a therapeutic agent if it demonstrates a statistically significant effect across an appropriate population. In some embodiments, an appropriate population is a population of subjects suffering from and / or susceptible to a disease, disorder or condition. In some embodiments, an appropriate population is a population of model organisms. In some embodiments, an appropriate population may be defined by one or more criterion such as age group, gender, genetic background, preexisting clinical conditions, prior exposure to therapy. In some embodiments, a therapeutic agent is a substance that alleviates, ameliorates, relieves, inhibits, prevents, delays onset of, reduces severity of, and / or reduces incidence of one or more symptoms or features of a disease, disorder, and / or condition in a subject when administered to the subject in an effective amount. In some embodiments, a “therapeutic agent” is an agent that has been or is required to be approved by a government agency before it can be marketed for Page 35 of 20113318736vlAttorney Docket No.: 2010581-1667administration to humans. In some embodiments, a “therapeutic agent” is an agent for which a medical prescription is required for administration to humans. In some embodiments, a therapeutic agent is a provided compound, e.g., a provided oligonucleotide.

[0088] Therapeutically effective amount: As used herein, the term “therapeutically effective amount” means an amount of a substance (e.g., a therapeutic agent, composition, and / or formulation) that elicits a desired biological response when administered as part of a therapeutic regimen. In some embodiments, a therapeutically effective amount of a substance is an amount that is sufficient, when administered to a subject suffering from or susceptible to a disease, disorder, and / or condition, to treat, diagnose, prevent, and / or delay the onset of the disease, disorder, and / or condition. As will be appreciated by those of ordinary skill in this art, the effective amount of a substance may vary depending on such factors as the desired biological endpoint, the substance to be delivered, the target cell or tissue, etc. For example, the effective amount of compound in a formulation to treat a disease, disorder, and / or condition is the amount that alleviates, ameliorates, relieves, inhibits, prevents, delays onset of, reduces severity of and / or reduces incidence of one or more symptoms or features of the disease, disorder, and / or condition. In some embodiments, a therapeutically effective amount is administered in a single dose; in some embodiments, multiple unit doses are required to deliver a therapeutically effective amount.

[0089] Treat: As used herein, the term “treat,” “treatment,” or “treating” refers to any method used to partially or completely alleviate, ameliorate, relieve, inhibit, prevent, delay onset of, reduce severity of, and / or reduce incidence of one or more symptoms or features of a disease, disorder, and / or condition. Treatment may be administered to a subject who does not exhibit signs of a disease, disorder, and / or condition. In some embodiments, treatment may be administered to a subject who exhibits only early signs of the disease, disorder, and / or condition, for example for the purpose of decreasing the risk of developing pathology associated with the disease, disorder, and / or condition.

[0090] Unsaturated: The term "unsaturated," as used herein, means that a moiety has one or more units of unsaturation.

[0091] Wild-type: As used herein, the term “wild-type” has its art-understood meaning that refers to an entity having a structure and / or activity as found in nature in a “normal” (as contrasted with mutant, diseased, altered, etc.) state or context. Those of ordinary skill in the art will appreciate that wild type genes and polypeptides often exist in multiple different forms (e.g., alleles).

[0092] As those skilled in the art will appreciate, methods and compositions described herein relating to provided compounds (e.g., oligonucleotides) generally also apply to pharmaceutically acceptable salts of such compounds.Description of Certain Embodiments

[0093] Oligonucleotides are useful tools for a wide variety of applications. For example, oligonucleotides as described herein are useful in therapeutic, diagnostic, and research applications, including the treatment of Page 36 of 20113318736vlAttorney Docket No.: 2010581-1667a variety of HTT-related conditions, disorders, and diseases, including Huntington’s disease. The use of naturally occurring nucleic acids (e.g., unmodified DNA or RNA) is limited, for example, by their susceptibility to endo- and exo-nucleases. As such, various synthetic counterparts have been developed to circumvent these shortcomings and / or to further improve various properties and activities. These include synthetic oligonucleotides that contain chemical modifications, e.g., base modifications, sugar modifications, backbone modifications, etc., which, among other things, render these molecules less susceptible to degradation and improve other properties and / or activities. From a structural point of view, modifications to internucleotidic linkages can introduce chirality, and certain properties may be affected by configurations of linkage phosphorus atoms of oligonucleotides. For example, binding affinity, sequence specific binding to complementary RNA, stability to nucleases, cleavage of target HTT nucleic acids, delivery, pharmacokinetics, etc. can be affected by, inter alia, chirality of backbone linkage phosphorus atoms. Among other things, the present disclosure provides technologies for controlling and / or utilizing various structural elements, e.g., sugar modifications and patterns thereof, nucleobase modifications and patterns thereof, modified internucleotidic linkages and patterns thereof, linkage phosphorus stereochemistry and patterns thereof, additional chemical moieties (moieties that are not typically in an oligonucleotide chain) and patterns thereof, etc., and various combinations of one or more or all of such structural elements, in oligonucleotides.

[0094] In some embodiments, provided oligonucleotides are oligonucleotides targeting HTT, and can reduce levels of HTT transcripts and / or one or more products encoded thereby. Such oligonucleotides are particularly useful for preventing and / or treating HTT-related conditions, disorders and / or diseases, including Huntington’s disease.

[0095] In some embodiments, the present disclosure provides an oligonucleotide as disclosed herein, e.g., in Table 1. In some embodiments, the present disclosure provides an oligonucleotide that has a base sequence comprising at least 10 contiguous bases of an oligonucleotide disclosed herein. In some embodiments, the present disclosure provides an oligonucleotide whose base sequence is or comprises at least 10 contiguous bases of a base sequence selected from Table B-l, wherein each T is independently and optionally replaced with U and vice versa. In some embodiments, the present disclosure provides an oligonucleotide whose base sequence is or comprises a base sequence selected from Table B-l, wherein each T is independently and optionally replaced with U and vice versa.

[0096] In some embodiments, an oligonucleotide composition is stereorandom. In some embodiments, an oligonucleotide composition is chirally controlled.

[0097] In some embodiments, internucleotidic linkages of an oligonucleotide comprise or consist of 1-5, 1-10, 1-15, 1-20, 1-25, 1-30, 1-40, 1-50, or 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more chirally controlled internucleotidic linkages. In some embodiments, an oligonucleotide composition of the present disclosure comprises oligonucleotides of the same constitution, wherein one or more internucleotidic linkages are chirally controlled and one or more internucleotidic linkages are stereorandom (not chirally controlled). In some embodiments, the present disclosure provides an oligonucleotide Page 37 of 20113318736vlAttorney Docket No.: 2010581-1667composition wherein the oligonucleotides comprise at least one chirally controlled internucleotidic linkage. In some embodiments, the present disclosure provides an oligonucleotide composition wherein the oligonucleotides are stereorandom or not chirally controlled. In some embodiments, in an oligonucleotide, at least one internucleotidic linkage is stereorandom and at least one internucleotidic linkage is chirally controlled.

[0098] In some embodiments, an oligonucleotide comprises a natural phosphate linkage. In some embodiments, an oligonucleotide comprises a phosphorothioate internucleotidic linkage. In some embodiments, an oligonucleotide comprises a PN internucleotidic linkage. In some embodiments, an oligonucleotide comprises a phosphoramidate internucleotidic linkage. In some embodiments, an oligonucleotide comprises a phosphoryl guanidine internucleotidic linkage. In some embodiments, an oligonucleotide comprises a natural phosphate linkage and a phosphorothioate internucleotidic linkage. In some embodiments, an oligonucleotide comprises a natural phosphate linkage, a phosphorothioate internucleotidic linkage and a PN internucleotidic linkage (e.g., nOOl, MsPA, etc.). In some embodiments, an oligonucleotide comprises a natural phosphate linkage, a phosphorothioate internucleotidic linkage and a phosphoramidate internucleotidic linkage.

[0099] In some embodiments, internucleotidic linkages of an oligonucleotide comprise or consist of one or more negatively charged internucleotidic linkages (e.g., phosphorothioate internucleotidic linkages, natural phosphate linkages, etc.). In some embodiments, internucleotidic linkages of an oligonucleotide comprise or consist of one or more negatively charged chiral internucleotidic linkages (e.g., phosphorothioate internucleotidic linkages). In some embodiments, internucleotidic linkages of an oligonucleotide comprise or consist of one or more non- negatively charged internucleotidic linkages. In some embodiments, internucleotidic linkages of an oligonucleotide comprise or consist of one or more neutral chiral internucleotidic linkages. In some embodiments, the present disclosure pertains to an oligonucleotide which comprises at least one neutral or non-negatively charged internucleotidic linkage as described in the present disclosure.Huntingtin’s Disease (HD)

[0100] Among other things, the present disclosure provides methods for reducing levels of mutant HTT transcripts and / or products encoded thereby. In some embodiments, the present disclosure provides methods for preventing or treating conditions, diseases or disorders associated with HTT transcripts and / or products encoded thereby. In some embodiments, a HTT mutation is or comprises expanded CAG repeat. In some embodiments, a mutant HTT transcript comprises expanded CAG repeat. In some embodiments, a mutant HTT polypeptide comprises expanded polyQ (e.g., encoded by an expanded CAG repeat). In some embodiments, a condition, disease or disorder is Huntington’s disease.

[0101] Huntington’s disease (HD) is a neurodegenerative disorder reportedly caused by a mutation of the HTT (huntingtin) gene. Alteration of this widely expressed single gene reportedly results in a progressive,Page 38 of 20113318736vlAttorney Docket No.: 2010581-1667neurodegenerative disorder with a large number of characteristic symptoms. In some embodiments, a HD-related mutation is an expansion of a CAG repeat region in the HTT gene, wherein a larger expansion reportedly results in greater severity of the disease and an earlier age of onset. The mutation reportedly results in a variety of motor, emotional and cognitive symptoms, and results in the formation of huntingtin aggregates in brain.

[0102] The CAG expansion reportedly results in the expansion of a poly-glutamine tract in the huntingtin protein, a 350 kDa protein (Huntington Disease Collaborative Research Group, 1993. Cell. 72:971-83). The normal and expanded HD allele sizes have reportedly been found to be, e.g., CAG 6-37 and CAG 35-121 repeats or longer, respectively. Longer repeat sequences are reportedly associated with earlier disease onset. The absence of an HD phenotype in individuals deleted for one copy of huntingtin, or increased severity of disease in those homozygous for the expansion reportedly suggests that the mutation does not result in a loss of function (Trottier et al., 1995, Nature Med., 10:104-110). Transcriptional deregulation and loss of function of transcriptional coactivator proteins have reportedly been implicated in HD pathogenesis. Mutant huntingtin has reportedly been shown specifically to disrupt activator-dependent transcription in the early stages of HD pathogenesis (Dunah et al., 2002. Science 296:2238-2243).

[0103] In one report gene profiling of human blood identified 322 mRNAs that show significantly altered expression in HD blood samples as compared to normal or presymptomatic individuals. Expression of marker genes was similarly substantially altered in post-mortem brain samples from HD caudate, suggesting that upregulation of genes in blood samples reflects disease mechanisms found in brain. Monitoring of gene expression may provide a sensitive and quantitative method to monitor disease progression, especially in the early stages of disease in both animal models and human patients (Borovecki et al., 2005, Proc. Natl. Acad. Sci. USA 102:11023-11028).

[0104] Huntington’s disease has been reported to be an autosomal dominant disorder, with an onset generally in mid-life, although cases of onset from childhood to over 70 years of age have been documented. An earlier age of onset is reportedly associated with paternal inheritance, with 70% of juvenile cases being inherited through the father.

[0105] In some embodiments, symptoms of Huntington’ s disease have an emotional, motor and cognitive component. One symptom, chorea is a characteristic feature of the motor disorder and is defined as excessive spontaneous movements which are irregularly timed, randomly distributed and abrupt. It can vary from being barely perceptible to severe. Other frequently observed symptoms or abnormalities include dystonia, rigidity, bradykinesia, ocularmotor dysfunction, tremor, etc. Voluntary movement disorders as symptoms include fine motor incoordination, dysathria, and dysphagia. Emotional disorders or symptoms commonly include depression and irritability, and cognitive component comprises subcortical dementia (Mangiarini et al. 1996. Cell 87:493-506). It is reported that changes in HD brains are widespread and include neuronal loss and gliosis, particularly in the cortex and striatum (Vonsattel and DiFiglia. 1998. J. Neuropathol. Exp. Neurol. 57:369-384).Page 39 of 20113318736vlAttorney Docket No.: 2010581-1667

[0106] Certain information related to HTT and HTT-related conditions, disorders or diseases has been reported in, for example: Kremer et al. 1994. N. E. J. Med. 330: 1401; Kordasiewicz et al. 2012 Neuron 74: 1031-1044; Carroll et al. 2011 Mol. Ther. 19: 2178-2185; Warby et al. 2009 Am. J. Hum. Genet. 84: 351-366; Pfister et al. 2009 Current Biol. 19: 774-778; Kay et al. 2015 Mol. Ther. 23: 1759-1771; Kay et al. 2014 Clin. Genet. 86: 29-36; Lee et al. 2015. Am. J. Hum. Genet. 97: 435-444; Skotte et al. 2014. PLOS ONE 9: el07434; Southwell et al. 2014. Mol. Ther. 22: 2093-2106; Australian Pat. Publications AU2017276286 and AU2007210038; European Pat. Publications EP3277814 and EP3210633; International Pat. Publication W02018145009; and US Pat. Publication US20180273945.

[0107] In some embodiments, an oligonucleotide is complementary to a portion of an HTT nucleic acid sequence, e.g., an HTT gene sequence, an HTT mRNA sequence, etc. In some embodiments, the base sequence of such a portion is characteristic of HTT in that no other genomic or transcript sequences have the same sequence as the portion. In some embodiments, a portion of a gene that is complimentary to an oligonucleotide is referred to as the target sequence of the oligonucleotide.

[0108] In some embodiments, an HTT gene sequence (or a portion thereof, e.g., complementary to an oligonucleotide as described herein) is an HTT gene sequence (or a portion thereof) known in the art or reported in the literature. Certain nucleotide and amino acid sequences of a human HTT can be found in public sources, for example, one or more publicly available databases, e.g., GenBank, UniProt, OMIM, etc. Those skilled in the art will appreciate that, for example, where a described nucleic acid sequence may be or include a genomic sequence, transcripts, splicing products, and / or encoded proteins, etc., may readily be appreciated from such genomic sequence.

[0109] In some embodiments, the Huntingtin (HTT) gene or a product thereof, or a variant or portion thereof, may be referred to as HTT.

[0110] In some embodiments, the present disclosure provides technologies, e.g., oligonucleotides, compositions, methods, etc., related to the HTT gene or a product encoded thereby (a transcript, a protein (e.g., various variants of the Huntingtin protein, etc.). In some embodiments, the present disclosure provides technologies, including oligonucleotides and compositions and methods thereof, for treatment of Huntington’s disease. In some embodiments, HTT comprises one or more mutations. In some embodiments, such mutations are associated with reduced biological functions of Huntingtin protein in a subject suffering from and / or susceptible to Huntington’s disease. In some embodiments of Huntington’s disease, one or both alleles of HTT are mutant.

[0111] In some embodiments, an oligonucleotide as described herein is capable of decreasing the level, activity and / or expression of an HTT gene is useful in a method of preventing or treating an HTT-related condition, disorder or disease, e.g., Huntington’s disease, and / or delaying the onset of and / or the severity of one or more symptoms of Huntington’s disease.

[0112] In some embodiments, the present disclosure provides methods for preventing or treating an HTT-related condition, disorder or disease, by administering to a subject suffering from or susceptible to such a Page 40 of 20113318736vlAttorney Docket No.: 2010581-1667condition, disorder or disease a therapeutically effective amount of a provided oligonucleotide or a composition thereof. In some embodiments, a composition is a chirally controlled oligonucleotide composition.

[0113] In some embodiments, HTT refers to a gene or a gene product thereof (including but not limited to, a nucleic acid, including but not limited to a DNA or RNA, or a wild-type or mutant protein encoded thereby), from any species, and which may be also known as: HTT, HD, IT15, huntingtin, Huntingtin, or LOMARS; External IDs: OMIM: 613004, MGI: 96067, HomoloGene: 1593, GeneCards: HTT; Species: Human: Entrez: 3064; Ensembl: ENSG00000197386; UniProt: P42858; RefSeq (mRNA): NM.002111; RefSeq (protein): NP_002102; Location (UCSC): Chr 4: 3.04 - 3.24 Mb; Species: Mouse: Entrez: 15194; Ensembl: ENSMUSG00000029104; UniProt: P42859; RefSeq (mRNA): NM_010414; RefSeq (protein): NP_034544; Location (UCSC): Chr 5: 34.76 - 34.91 Mb. Additional HTT sequences, including variants thereof, from human, mouse, rat, monkey, etc., are readily available to those of skill in the art. In some embodiments, HTT is a human or mouse HTT, which is wild-type or mutant. Example useful reported sequences include NC_000004.12 chr 4 (3074681..3243960), NM_001388492.1, NP_001375421.1, NM_002111.8, NP_002102.4, which include sequences for genomic sequences, transcript sequences, mRNA sequences, polypeptide sequences, exon sequences, intron sequences, etc.

[0114] In some embodiments, a HTT protein is unmodified or modified. In some embodiments, a HTT protein has any one or more modifications of: 9 N6-acetyllysine; 176 N6-acetyllysine; 234 N6-acetyllysine; 343 N6-acetyllysine; 411 Phosphoserine; 417 Phosphoserine; 419 Phosphoserine; 432 Phosphoserine; 442 N6-acetyllysine; 640 Phosphoserine; 643 Phosphoserine; 1179 Phosphoserine; 1199 Phosphoserine; 1870 Phosphoserine; and / or 1874 Phosphoserine.Mutant HTT

[0115] In some embodiments, a mutant HTT is designated mHTT, muHTT, m HTT, mu HTT, MU HTT, or the like, wherein m or mu indicate mutant. In some embodiments, a wild type HTT is designated wild-type HTT, wtHTT, wt HTT, WT HTT, WTHTT, or the like, wherein wt indicates wild-type. In some embodiments, a human HTT is designated hHTT. In some embodiments, a mutant HTT is designated mHTT. In some embodiments, when a mouse is utilized, a mouse HTT may be referred to as mHTT as those skilled in the art will appreciate.

[0116] In some embodiments, a mutant HTT comprises an expanded CAG repeat region (e.g., 36-121, 36-250, 37-121, 40-121, repeats or longer). In some embodiments, a mutant HTT comprises expanded CAG repeat(e.g., 36-121, 36-250, 37- 121,40- 121, repeats or longer) in exon 1 o aHTT gene. In some embodiments, a mutant HTT gene encodes an expanded polyglutamine (polyQ) domain in a HTT polypeptide. In some embodiments, a mutant HTT gene comprises expanded CAG repeat (e.g., 36-121, 36-250, 37-121, 40-121, repeats or longer) in exon 1 and encodes an expanded polyglutamine (polyQ) domain in a HTT polypeptide. In some embodiments, a transcript comprises (CAG)n wherein n is about 27 or above. In some embodiments, nis about or at least about 27, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200.Page 41 of 20113318736vlAttorney Docket No.: 2010581-1667In some embodiments, n is about 27-35. In some embodiments, n is 36 or more. In some embodiments, n is about 36-39. In some embodiments, n is 40 or more. In some embodiments, n is about 40-50. In some embodiments, n is about 50 or more. In some embodiments, n is about 40-60. In some embodiments, n is about 50 or more. In some embodiments, n is about 60 or more. In some embodiments, n is about 70 or more. In some embodiments, n is about 80 or more. In some embodiments, n is about 90 or more. In some embodiments, n is about 100 or more. In some embodiments, a mutant polypeptide comprises (Q)q, wherein q is about or at least about 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 40, 50, 60, 70, 80, 90 or 100. In some embodiments, q is about or at least about 9. In some embodiments, q is about or at least about 12. In some embodiments, q is about or at least about 13. In some embodiments, q is about or at least about 14. In some embodiments, q is about or at least about 15. In some embodiments, q is about or at least about 16. In some embodiments, q is about or at least about 17. In some embodiments, q is about or at least about 18. In some embodiments, q is about or at least about 19. In some embodiments, q is about or at least about 20. In some embodiments, q is about or at least about 21. In some embodiments, q is about or at least about 22. In some embodiments, q is about or at least about 23. In some embodiments, q is about or at least about 24. In some embodiments, q is about or at least about 25. In some embodiments, q is about 9-200. In some embodiments, q is about 9-150. In some embodiments, q is about 13-150. In some embodiments, q is about 15-150. In some embodiments, q is about 20-150.

[0117] In some embodiments, a mutant HTT transcript, e.g., mRNA, contains only exon 1 and a portion of intron 1. In some embodiments, a mutant HTT transcript, e.g., mRNA, does not contain exon 2. In some embodiments, a mutant HTT transcript, e.g., mRNA, does not contain exon 64. In some embodiments, a mutant HTT transcript, e.g., mRNA, does not contain exon 65. In some embodiments, a mutant HTT transcript, e.g., mRNA, does not contain exon 66. In some embodiments, a mutant HTT transcript, e.g., mRNA, does not contain exon 67. In some embodiments, a mutant transcript, e.g., mRNA, encodes PGPAVAEEPLHRP. In some embodiments, a mutant HTT polypeptide comprises PGPAVAEEPLHRP.Mutant HTT - HTT la

[0118] In some embodiments, a HTT transcript comprises one or more cryptic polyadenylation (polyA) signals in intron 1 of a HTT gene. In some embodiments, a HTT transcript utilizes one or more cryptic polyadenylation (polyA) signals in intron 1 of a HTT gene. In some embodiments, a HTT transcript, e.g., mRNA, is or comprises exon 1 and parts of intron 1 of a HTT gene and no other exons (maybe referred herein as “HTTla”). According to some reports, a HTTla transcript, e.g., mRNA, can encode PGPAVAEEPLHRP, and HTTla polypeptides comprising and / or ending with PGPAVAEEPLHRP have been reported.

[0119] In some embodiments, a HTTla transcript consists of exon 1 and parts of intron 1 of a HTT gene. In some embodiments, a HTTla transcript is polyadenylated. In some embodiments, a HTTla transcript encodes an HTTla polypeptide.

[0120] HTT transcripts using cryptic polyA sites in HTT intron 1 and polypeptides encoded thereby have Page 42 of 20113318736vlAttorney Docket No.: 2010581-1667been widely reported, and according to various reports, are associated with Huntington’s diseases. See, e.g., Neueder, A., handles, C., Ghosh, R. et al. The pathogenic exon 1 HTT protein is produced by incomplete splicing in Huntington’s disease patients. Set Rep 7, 1307 (2017) and references cited therein. For example, according to some reports, a HTTla transcript utilizes a polyA site at 7327 bp into intron 1. According to various reports, HTTla polypeptides can be aggregation prone. In some embodiments, a HTTla polypeptide comprises of consists of amino acid sequences encoded by exon 1 and intron 1 or a portion thereof. In some embodiments, a HTTla polypeptide comprises and / or ends with PGPAVAEEPLHRP. In some embodiments, the base sequence of a HTTla transcript comprises SEQ ID NO: 1 or a characteristic portion thereof. In some embodiments, the base sequence of a HTTla transcript comprises SEQ ID NO: 2 or a characteristic portion thereof. In some embodiments, a transcript is a pre-mRNA. In some embodiments, a transcript is a mRNA. In some embodiments, the base sequence of a HTTla mRNA comprises SEQ ID NO: 1 or a characteristic portion thereof. In some embodiments, the base sequence of a HTTla mRNA comprises SEQ ID NO: 2 or a characteristic portion thereof. In some embodiments, a HTTla polypeptide comprises PGPAVAEEPLHRP. GTGAGTTTGGGCCCGCTGCAGCTCCCTGTCCCGGCGGGTCCCAGGCTACGGCGGGGATGGCGGTAACCCTGCA GCCTGCGGGCCGGCGACACGAACCCCCGGCCCCGCAGAGACAGAGTGACCCAGCAACCCAGAGCCCATGAGGG ACACCCGCCCCCTCCTGGGGCGAGGCCTTCCCCCACTTCAGCCCCGCTCCCTCACTTGGGTCTTCCCTTGTCC TCTCGCGAGGGGAGGCAGAGCCTTGTTGGGGCCTGTCCTGAATTCACCGAGGGGAGTCACGGCCTCAGCCCTC TCGCCCTTCGCAGGATGCGAAGAGTTGGGGCGAGAACTTGTTTCTTTTTATTTGCGAGAAACCAGGGCGGGGG TTCTTTTAACTGCGTTGTGAAGAGAACTTGGAGGAGCCGAGATTTGCTCAGTGCCACTTCCCTCTTCTAGTCT GAGAGGGAAGAGGGCTGGGGGCGCGGGACACTTCGAGAGGAGGCGGGGTTTGGAGCTGGAGAGATGTGGGGGC AGTGGATGACATAATGCTTTTAGGACGCCTCGGCGGGAGTGGCGGGGCAGGGGGGGGGCGGGGAGTGAGGGCG CGTCCAATGGGAGATTTCTTTTCCTAGTGGCACTTAAAACAGCCTGAGATTTGAGGCTCTTCCTACATTGTCA GGACATTTCATTTAGTTCATGATCACGGTGGTAGTAACACGATTTTAAGCACCACCTAAGAGATCTGCTCATC TAAGCCTAAGTTGGTCTGCAGGCGTTTGAATGAGTTGTGGTTGCCAAGTAAAGTGGTGAACTTACGTGGTGAT TAATGAAATTATCTTAAATATTAGGAAGAGTTGATTGAAGTTTTTTGCCTATGTGTGTTGGGAATAAAACCAA CACGTTGCTGATGGGGAGGTTAATTGCCGAGGGATGAATGAGGTGTACATTTTACCAGTATTCCAGTCAGGCT TGCCAGAATACGGGGGGTCCGCAGACTCCGTGGGCATCTCAGATGTGCCAGTGAAAGGGTTTCTGTTTGCTTC ATTGCTGACAGCTTGTTACTTTTTGGAAGCTAGGGGTTTCTGTTGCTTGTTCTTGGGGAGAATTTTTGAAACA GGAAAAGAGAGACCATTAAAACATCTAGCGGAACCCCAGGACTTTCCCTGGAAGTCTGTGTGTCGAGTGTACA GTAGGAGTTAGGAAGTACTCTGGTGCAGTTCAGGCCTTTCTCTTACCTCTCAGTATTCTATTTCCGATCTGGA TGTGTCCCAGATGGCATTTGGTAAGAATATCTCTGTTAAGACTGATTAATTTTTAGTAATATTTCTTGTTCTT TGTTTCTGTTATGATCCTTGTCTCGTCTTCAAAGTTTAATTAGAAAATGATTCGGAGAGCAGTGTTAGCTTAT TTGTTGGAATAAAATTTAGGAATAAATTATTCTAAAGGATGGAAAAACTTTTTGGATATTTGGAGAAATTTTA AAACAATTTGGCTTATCTCTTCAGTAAGTAATTTCTCATCCAGAAATTTACTGTAGTGCTTTTCTAGGAGGTA GGTGTCATAAAAGTTCACACATTGCATGTATCTTGTGTAAACACTAAACAGGGCTCCTGATGGGAAGGAAGAC CTTTCTGCTGGGCTGCTTCAGACACTTGATCATTCTAAAAATATGCCTTCTCTTTCTTATGCTGATTTGACAGPage 43 of 20113318736vlAttorney Docket No.: 2010581-1667 AACCTGCATTTGCTTATCTTCAAAATATGGGTATCAAGAAATTTCCTTTGCTGCCTTGACAAAGGAGATAGAT TTTGTTTCATTACTTTAAGGTAATATATGATTACCTTATTTAAAAAATTTAATCAGGACTGGCAAGGTGGCTT ACACCTTTAATCCGAGCACTTTGGGAGGCCTAGGTGGACGAATCACCTGAGGTCAGGAGTTTGAGACCAGCCT GGCTAACATGGTGAAACCCTGTCTCTACTAAAAATACAAAAATTAGCTGGTCATGGTGGCACGTGCCTGTAAT CCAAGCTACCTGGGAGGCTGAGGCAGGAAAATCGCTTGAACCCGGGAGGCAGAGTCTGCAGTGAGTTGAGATC ACGCCACTGCACTCCAGCCTGGGTGACAGAGCGAGACTCTATCTCAAAAAAAATTTTTTTTAATGTATTATTT TTGCATAAGTAATACATTGACATGATACAAATTCTGTAATTACAAAAGGGCAATAATTAAAATATCTTCCTTC CACCCCTTTCCTCTGAGTACCTAACTTTGTCCCCAAGAACAAGCACTATTTCAGTTCCTCATGTATCCTGCCA GATATAACCTGTTCATATTGTAAGATAGATTTAAAATGCTCTAAAAACAAAAGTAGTTTAGAATAATATATAT CTATATATTTTTTGAGATGTAGTCTCACATTGTCACCCAGGCTGGAGTGCAGTGATACAATCTCGGCTCACTG CAGTCTCTGCCTCCCAGGTTCAAATGCTTCTCCTGCCTCAGCCTTCTGAGTAGCTGGGATTACAGGCGCCCAC CACCATGTCCAGCTAATTTTTGTATTTTTAGTAGAGATGGGGTTTCACCATGTTGGCCAGGCTGGTCTTGAAC TCCTGACCTTGTGATCTGTCCACCTCGGCCTCCCAAAGTGCTGGGATTACAGGTGTGAGCCACCATGCCTGGC TAGAATAATAACTTTTAAAGGTTCTTAGCATGCTCTGAAATCAACTGCATTAGGTTTATTTATAGTTTTATAG TTATTTTA (SEQ ID NO: 1) GTGAGTTTGGGCCCGCTGCAGCTCCCTGTCCCGGCGGGTCCCAGGCTACGGCGGGGATGGCGGTAACCCTGCA GCCTGCGGGCCGGCGACACGAACCCCCGGCCCCGCAGAGACAGAGTGACCCAGCAACCCAGAGCCCATGAGGG ACACCCGCCCCCTCCTGGGGCGAGGCCTTCCCCCACTTCAGCCCCGCTCCCTCACTTGGGTCTTCCCTTGTCC TCTCGCGAGGGGAGGCAGAGCCTTGTTGGGGCCTGTCCTGAATTCACCGAGGGGAGTCACGGCCTCAGCCCTC TCGCCCTTCGCAGGATGCGAAGAGTTGGGGCGAGAACTTGTTTCTTTTTATTTGCGAGAAACCAGGGCGGGGG TTCTTTTAACTGCGTTGTGAAGAGAACTTGGAGGAGCCGAGATTTGCTCAGTGCCACTTCCCTCTTCTAGTCT GAGAGGGAAGAGGGCTGGGGGCGCGGGACACTTCGAGAGGAGGCGGGGTTTGGAGCTGGAGAGATGTGGGGGC AGTGGATGACATAATGCTTTTAGGACGCCTCGGCGGGAGTGGCGGGGCAGGGGGGGGGCGGGGAGTGAGGGCG CGTCCAATGGGAGATTTCTTTTCCTAGTGGCACTTAAAACAGCCTGAGATTTGAGGCTCTTCCTACATTGTCA GGACATTTCATTTAGTTCATGATCACGGTGGTAGTAACACGATTTTAAGCACCACCTAAGAGATCTGCTCATC TAAGCCTAAGTTGGTCTGCAGGCGTTTGAATGAGTTGTGGTTGCCAAGTAAAGTGGTGAACTTACGTGGTGAT TAATGAAATTATCTTAAATATTAGGAAGAGTTGATTGAAGTTTTTTGCCTATGTGTGTTGGGAATAAAACCAA CACGTTGCTGATGGGGAGGTTAATTGCCGAGGGATGAATGAGGTGTACATTTTACCAGTATTCCAGTCAGGCT TGCCAGAATACGGGGGGTCCGCAGACTCCGTGGGCATCTCAGATGTGCCAGTGAAAGGGTTTCTGTTTGCTTC ATTGCTGACAGCTTGTTACTTTTTGGAAGCTAGGGGTTTCTGTTGCTTGTTCTTGGGGAGAATTTTTGAAACA GGAAAAGAGAGACCATTAAAACATCTAGCGGAACCCCAGGACTTTCCCTGGAAGTCTGTGTGTCGAGTGTACA GTAGGAGTTAGGAAGTACTCTGGTGCAGTTCAGGCCTTTCTCTTACCTCTCAGTATTCTATTTCCGATCTGGA TGTGTCCCAGATGGCATTTGGTAAGAATATCTCTGTTAAGACTGATTAATTTTTAGTAATATTTCTTGTTCTT TGTTTCTGTTATGATCCTTGTCTCGTCTTCAAAGTTTAATTAGAAAATGATTCGGAGAGCAGTGTTAGCTTAT TTGTTGGAATAAAATTTAGGAATAAATTATTCTAAAGGATGGAAAAACTTTTTGGATATTTGGAGAAATTTTA AAACAATTTGGCTTATCTCTTCAGTAAGTAATTTCTCATCCAGAAATTTACTGTAGTGCTTTTCTAGGAGGTAPage 44 of 20113318736vlAttorney Docket No.: 2010581-1667 GGTGTCATAAAAGTTCACACATTGCATGTATCTTGTGTAAACACTAAACAGGGCTCCTGATGGGAAGGAAGAC CTTTCTGCTGGGCTGCTTCAGACACTTGATCATTCTAAAAATATGCCTTCTCTTTCTTATGCTGATTTGACAG AACCTGCATTTGCTTATCTTCAAAATATGGGTATCAAGAAATTTCCTTTGCTGCCTTGACAAAGGAGATAGAT TTTGTTTCATTACTTTAAGGTAATATATGATTACCTTATTTAAAAAATTTAATCAGGACTGGCAAGGTGGCTT ACACCTTTAATCCGAGCACTTTGGGAGGCCTAGGTGGACGAATCACCTGAGGTCAGGAGTTTGAGACCAGCCT GGCTAACATGGTGAAACCCTGTCTCTACTAAAAATACAAAAATTAGCTGGTCATGGTGGCACGTGCCTGTAAT CCAAGCTACCTGGGAGGCTGAGGCAGGAAAATCGCTTGAACCCGGGAGGCAGAGTCTGCAGTGAGTTGAGATC ACGCCACTGCACTCCAGCCTGGGTGACAGAGCGAGACTCTATCTCAAAAAAAATTTTTTTTAATGTATTATTT TTGCATAAGTAATACATTGACATGATACAAATTCTGTAATTACAAAAGGGCAATAATTAAAATATCTTCCTTC CACCCCTTTCCTCTGAGTACCTAACTTTGTCCCCAAGAACAAGCACTATTTCAGTTCCTCATGTATCCTGCCA GATATAACCTGTTCATATTGTAAGATAGATTTAAAATGCTCTAAAAACAAAAGTAGTTTAGAATAATATATAT CTATATATTTTTTGAGATGTAGTCTCACATTGTCACCCAGGCTGGAGTGCAGTGATACAATCTCGGCTCACTG CAGTCTCTGCCTCCCAGGTTCAAATGCTTCTCCTGCCTCAGCCTTCTGAGTAGCTGGGATTACAGGCGCCCAC CACCATGTCCAGCTAATTTTTGTATTTTTAGTAGAGATGGGGTTTCACCATGTTGGCCAGGCTGGTCTTGAAC TCCTGACCTTGTGATCTGTCCACCTCGGCCTCCCAAAGTGCTGGGATTACAGGTGTGAGCCACCATGCCTGGC TAGAATAATAACTTTTAAAGGTTCTTAGCATGCTCTGAAATCAACTGCATTAGGTTTATTTATAGTTTTATAG TTATTTTAAATAAAATGCATATTTGTCATATTTCTCTGTATTTTGCTGTTGAGAAAGGAGGTATTCACTAATT TTGAGTAACAAACACTGCTCACAAAGTTTGGATTTTGGCAGTTCTGTTCACGTGCTTCAGCCAAAAAATCCTC TTCTCAAAGTAAGATTGATGAAAGCAATTTAGAAAGTATCTGTTCTGTTTTTATGGCTCTTGCTCTTTGGTGT GGAACTGTGGTGTCACGCCATGCATGGGCCTCAGTTTATGAGTGTTTGTGCTCTGCTCAGCATACAGGATGCA GGAGTTCCTTATGGGGCTGGCTGCAGGCTCAGCAAATCTAGCATGCTTGGGAGGGTCCTCACAGTAATTAGGA GGCAATTAATACTTGCTTCTGGCAGTTTCTTATTCTCCTTCAGATTCCTATCTGGTGTTTCCCTGACTTTATT CATTCATCAGTAAATATTTACTAAACATGTACTATGTGCCTGGCACTGTTATAGGTGCAGGGCTCAGCAGTGA GCAGACAAAGCTCTGCCCTCGTGAAGCTTTCATTCTAATGAAGGACATAGACAGTAAGCAAGATAGATAAGTA AAATATACAGTACGTTAATACGTGGAGGAACTTCAAAGCAGGGAAGGGGATAGGGAAATGTCAGGGTTAATCG AGTGTTAACTTATTTTTATTTTTAAAAAAATTGTTAAGGGCTTTCCAGCAAAACCCAGAAAGCCTGCTAGACA AATTCCAAAAGAGCTGTAGCACTAAGTGTTGACATTTTTATTTTATTTTGTTTTGTTTTGTTTTTTTTGAGAC AGTTCTTGCTCTATCAGCCAGGCTGGAGTGCACTAGTGTGATCTTGGCTCACTGCAACCTCTGCCTCTTGGGT TCAAGTGATTCTCATGCCTCAGCCTCCTGTTTAGCTGGGATTATAGACATGCACTGCCATGCCTGGGTAATTTTTTTTTTTTCCCCCGAGACGGAGTCTTGCTCTGTCGCCCAGGCTGGAGTGCAGTGGC,GCGATCTC,AGC,TCAC. TGCAAGCTCCGCTTCCCGAGTTCACGCCATTCTCCTGCCTCAGTCTCCCAAGTAGCTGGGACTACAGGCGCCTG CCACCACGTCCAGCTAATTTTTTTGTATTTTTAATAGAGACGGGGTTTCACCGTGTTAGCCAGGATGATCTTG ATCTCCTGACCTCGTCATCCGCCGACCTTGTGATCCGCCCACCTCGGCCTCCCAAAGTGCTGGGATTACAGGC ATGAGCCACTGTGCCCGGCCACGCCTGGGTAATTTTGTATTTTAGTAGAGATGGGGTTTGCCATGATGAG CAGGCTGGTCTCGAACTCCCGGCCTCATGTGATCTGCCTGCCTTGGCCTCCCAAAGTGCTAGGATTACAGGCA TGAGCCACCATACCTGGCCAGTGTTGATATTTTAAATACGGTGTTCAGGGAAGGTCCACTGAGAAGACAGCTTPage 45 of 20113318736vlAttorney Docket No.: 2010581-1667TTTTTTTTTTTTTTTTTGGGGTTGGGGGGGAAGGTCTTGCTGTTTAACCGAGGGTGGAATGGAGTATGACTTAT,ATCGTAGCTCACTTCAGCCTTGAACTCCTGGGCTCAAGTGATCCTCCCACCTCAACCTCACAATGTGTTGGGACT ATAGGTGTGAGCCATCACACCTGGCCAGATGATGGCTTTTGAGTAAAGACCTCAAGCGAGTTAAGAGTCTAGT GTAAGGGTGTATGAAGTAGTGGTATTCCAGATGGGGGGAACAGGTCCAAAATCTTCCTGTTTCAGGAATAGCA AGGATGTCATTTTAGTTGGGTGAATTGAGTGAGGGGGACATTTGTAGTAAGAAGTAAGGTCCAAGAGGTCAAG GGAGTGCCATATCAGACCAATACTACTTGCCTTGTAGATGGAATAAAGATATTGGCATTTATGTGAGTGAGAT GGGATGTCACTGGAGGATTAGAGCAGAGGAGTAGCATGATCTGAATTTCAATCTTAAGTGAACTCTGGCTGAC AACAGAGTGAAGGGGAACACCGGCAAAAGCAGAAACCAGTTAGGAAGCCACTGCAGTGCTCAGATAAGCATGG TGGGTTCTGTCAGGGTACCGGCTGTCGGCTGTGGGCAGTGTGAGGAATGACTGACTGGATTTTGAATGCGGAA CCAACTGCACTTGTTGAACTCTGCTAAGTATAACAATTTAGCAGTAGCTTGCGTTATCAGGTTTGTATTCAGC TGCAAGTAACAGAAAATCCTGCTGCAATAGCTTAAACTGGTAACAAGCAAGAGCTTATCAGAAGACAAAAATA AGTCTGGGGAAATTCAACAATAAGTTAAGGAACCCAGGCTCTTTCTTTTTTTTTTTTTTGAAACGGAGTTTCG CTCTTGTCACCCGGGCTGGAGTGCAATGATGTGATCTCAGCTCACTAAAACCTCTACCTCCTGGGTTCAAGTG ATTCTTCTGCCTCAGCCTCCCAAGTAACTGGGATTACAGGCGTATACCACCATGCCCAGCTAATTTTTGTGTT TTTAGTAGAGATGGGGTTTCACCATGTTGGCCAGGCTGGTCTCGAACTTCTGACCTCAGGTGATCCACTCGCC TCAGCCTGCCAAAGTGCTGGGATTACAGGTTTGGGCCACTGCACCCGGTCAGAACCCAGGCTCTTTCTTATAC TTACCTTGCAAACCCTTGTTCTCATTTTTTCCCTTTGTATTTTTATTGTTGAATTGTAATAGTTCTTTATATA TTCTGGATACTGGATTCTTATCAGATAGATGATTTGTAAAAACTCTCCCTTCCTTTGGATTGTCTTTTTACTT TCTTGATAGTGTCTTTTGAAGTGTAAAAGTTTTTAATTTTGATGAAGTCGAGTTTATCTATTTTGTCTTTGGT TGCTGTGCTTCAAGTGTCATATCTAAGAAATCATTGTCTAATCCAAAGTCAAAAAGGTTTACTCCTATGTTTT CTTCTAAGAATTTTAGAGTTTTACATTTAAGTCTGATCCATTTTGAGTTAATTTTTATATATGGTTCAGGTAG AAGTCCAACTTTATTCTTTTCCATGTGGTTATTCAGTTGTCCCAGCACTGTTTGTTGAAGAGACTATTCTTTC CCCATGGAATTATCTTAGTACCCTTGTTGAAAATTAATCGTCCTTAATTGTATAAATTTATTTCTAGACTGTC AGTTCTACCTGTTGGTCTTTATGTCGATCCTGTGCCAGTACCATACAGTCTTGATTACTGAAGTTTGTGTCAC AGTTTAAATTCATGAAATGTGAGTTCTCCAACTTTGTTCCTTTTCAAGATTGATTTGGCCATGCTGGGTCCCT TGCATTTCCGTACGAATTGTAGGATCAGCTTGTCAGTTTCAACAAAGAAGCCAAGTAGGATTCTGAGAGGGAT TGTGTTGAATCTGTAGATCAACTTGGGGAGTATTCGCATCTTAACAATATTGTCTTCCACCTATGAACATGGG CAAACTTTGTGTAAATGGTCAGATTGTAAGTATTTCGGGCTGTGTGGGCACAGTGTCTCTGTCACAGCTACGC GGCTCTGCCATTGTAGCATGAAAGTAGCCATAAGCAATATGTATGAGTGTCTGTGTTCCAATAGAATTTTATT AATGACAAGGAAGTTTGAATTTCATATAATTTTCACCTGTCATGAGATAGTATTTGATTATTTTGGTCAACCA TTTAAAAATGTAAAAACATTTCTTAGCTTGTGAACTAGCCAAAAATATGCAGGTTATAGTTTTCCCACTCCTA GGTTAAAATATGATAGGACCACATTTGGAAAGCATTTCTTTTTTTTTTTTTTTTTTTTTTTTTGAGACGGAGT TTCACTCTTGTTGCCCAGGCTGGAGTGCAGTGGCGCGATCTCGGCTCACTGCAACCTCTGCCTCCCAGGTTCA AGACATTCTCCTGCACGGCCTCCCTAGTAGCTGGGATTACAGGCATGCGCCACCACACCCAGCTAATTTTGTA TTTTTAGTAGAGACGGGGTTTCTCCATGTTGGTCAGGCTGGTCTTGAACTCCTGACCTCAGGTGATCCACCCG CCTCAGCCTCCCAAAGTGCTGGGATTACAGGGTGTGAGCCACCACACCCTGCTGGAAAGCATTTCTTTTTTGGPage 46 of 20113318736vlAttorney Docket No.: 2010581-1667 CTGTTTTTGTTTTTTTTTTAAACTAGTTTTGAAAATTATAAAAGTTACACATATACATTATAAAAATATCTTC AAGCAGCACAGATGAAAAACAAAGCCCTTCTTGCAAGTCTGTCATCTTTGTCTAACTTCCTAAGAACAAAAGT GTTTCTTGTGTCTTCTTCCCAGATTTTAATATGCATATACAAGCATTTAAATGTGTCATTTTTTGTTTGCTTG ACTGAGATCACATTACATATGTATTTTTTTACTTAACAATGTGTCATAGATATTGTTCCATAGCAGTACCTGT AATTCTTAITAAITGCIATGIAATAIITIAGAAIITCII'TIIAAAAGAGGACTITTGGAGAIGTAAAGGCAAA GGTCTCACATTTTTGTGGCTGTAGAATGTGCTGGTGACATATTCTCTCTACCTTGAGAAGTCCCCATCCCCAT CACCTCCATTTCCTGTAAATAAGTCAACCACTTGATAAACTACCTTTGAATGGATCCACACTCAAAACATTTA GTCTTATTCAGACAACAAGGAGGAAA (SEQ ID NO: 2)Oligonucleotides

[0121] Among other things, the present disclosure provides oligonucleotides of various designs, which may comprises various nucleobases and patterns thereof, sugars and patterns thereof, internucleotidic linkages and patterns thereof, and / or additional chemical moieties and patterns thereof as described in the present disclosure.

[0122] In some embodiments, provided oligonucleotides can direct a decrease in the expression, level and / or activity of an HTT gene and / or one or more of its products (e.g., transcripts, mRNA, proteins, etc.) (e.g., a mutant HTT transcripts, a mutant HTT mRNA, mutant HTT proteins, etc). In some embodiments, provided oligonucleotides can direct a decrease in the expression, level and / or activity of an HTT gene (e.g., a mutant HTT gene) and / or one or more of its products in any cell of a subject or patient. In some embodiments, a cell is any cell that normally expresses HTT or produces HTT protein.

[0123] In some embodiments, provided oligonucleotides can direct a decrease in the expression, level and / or activity of an HTT target gene or a gene product (e.g., a mutant HTT target gene or a product thereof) and has a base sequence which consists of, comprises, or comprises a portion (e.g., a span of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or more contiguous bases) of the base sequence of an oligonucleotide disclosed herein, and the oligonucleotide comprises at least one non-naturally-occurring modification of a base, sugar and / or internucleotidic linkage.

[0124] In some embodiments, an oligonucleotide comprises one or more carbohydrate moieties. In some embodiments, an oligonucleotide comprises one or more lipid moieties. In some embodiments, an oligonucleotide comprises one or more targeting moieties. Non-limiting examples of such additional chemical moieties which can be conjugated to an oligonucleotide chain are described herein.

[0125] In some embodiments, provided oligonucleotides can direct a decrease in the expression, level and / or activity of a target gene, e.g., an HTT target gene, or a product thereof (e.g., a mutant HTT target gene or a product thereof). In some embodiments, provided oligonucleotides can direct a decrease in the expression, level and / or activity of an HTT target gene or a product thereof (e.g., a mutant HTT target gene or a product thereof) via RNase H-mediated knockdown. In some embodiments, provided oligonucleotides can direct a decrease in the expression, level and / or activity of an HTT target gene or a product thereof (e.g., a mutant Page 47 of 20113318736vlAttorney Docket No.: 2010581-1667HTT) by sterically blocking translation after binding to an HTT target gene mRNA (e.g., a mutant HTT target gene mRNA), and / or by altering or interfering with mRNA splicing. Regardless, however, the present disclosure is not limited to any particular mechanism. In some embodiments, the present disclosure provides oligonucleotides, compositions, methods, etc., capable of operating via double-stranded RNA interference, single-stranded RNA interference, RNase H-mediated knock-down, steric hindrance of translation, or a combination of two or more such mechanisms.

[0126] In some embodiments, oligonucleotides are antisense oligonucleotides (ASOs), in that they are oligonucleotides which have a base sequence which is antisense (e.g., complementary) to a target HTT sequence (e.g., a mutant HTT target sequence). In some embodiments, oligonucleotides are double-stranded siRNAs. In some embodiments, oligonucleotides are single-stranded siRNAs. Provided oligonucleotides and compositions thereof may be utilized for many purposes. For example, provided oligonucleotides can be coadministered or be used as part of a treatment regimen along with one or more treatment for Huntington’s disease or a symptom thereof, including but not limited to: aptamers, IncRNAs, IncRNA inhibitors, antibodies, peptides, small molecules, other oligonucleotides to HTT or other targets, and / or other agents capable of inhibiting the expression of an HTT transcript, reducing the level and / or activity of an HTT gene product (e.g., a mutant HTT gene product), and / or inhibiting the expression of a gene or reducing a gene product thereof which increases the expression, activity and / or level of an HTT transcript or an HTT gene product (e.g., a mutant HTT transcript or gene product), or a gene or gene product which is associated with an HTT-related disorder.

[0127] In some embodiments, an oligonucleotide, e.g., an oligonucleotide, comprises a structural element or a portion thereof described herein, e.g., in a Table 1. In some embodiments, an oligonucleotide, e.g., an oligonucleotide, comprises a base sequence (or a portion thereof), a chemical modification or a pattern of chemical modifications (or a portion thereof), and / or a format or a portion thereof described herein. In some embodiments, an oligonucleotide, e.g., an oligonucleotide as described herein, comprises the base sequence (or a portion thereof), pattern of chemical modifications (or a portion thereof), and / or a format of an oligonucleotide disclosed herein, e.g., in Table 1 or in the Figures, or otherwise disclosed herein. In some embodiments, such oligonucleotides, e.g., oligonucleotides reduce expression, level and / or activity of a gene, e.g., an HTT gene, or a gene product thereof (e.g., a mutant HTT target gene or a product thereof).

[0128] Among other things, provided oligonucleotides may hybridize to their target HTT nucleic acids (e.g., pre-mRNA, mature mRNA, etc.) (e.g., a mutant HTT pre-mRNA, a mutant HTT mRNA, etc.). For example, in some embodiments, an oligonucleotide can hybridize to an HTT nucleic acid derived from a DNA strand (either strand of the HTT gene). In some embodiments, an oligonucleotide can hybridize to an HTT transcript (e.g., a mutant HTT transcript). In some embodiments, an oligonucleotide can hybridize to an HTT nucleic acid in any stage of RNA processing, including but not limited to a pre-mRNA or a mature mRNA. In some embodiments, an oligonucleotide can hybridize to a portion of a HTT transcript comprising intron 1 or a portion thereof. In some embodiments, an oligonucleotide can hybridize to a portion of a HTT mRNA Page 48 of 20113318736vlAttorney Docket No.: 2010581-1667comprising intron 1 or a portion thereof. In some embodiments, the base sequence of a HTT transcript or mRNA comprises SEQ ID NO: 1 or a characteristic portion thereof. In some embodiments, the base sequence of a HTT transcript or mRNA comprises SEQ ID NO: 2 or a characteristic portion thereof. In some embodiments, an oligonucleotide hybridize to a portion of a HTT transcript, e.g., mRNA, wherein the base sequence of the portion is or comprises a characteristic portion of the SEQ ID NO: 1. In some embodiments, an oligonucleotide hybridize to a portion of a HTT transcript, e.g., mRNA, wherein the base sequence of the portion is or comprises a characteristic portion of the SEQ ID NO: 2. For example, in some embodiments, an oligonucleotide hybridize to a portion of a HTT transcript, e.g., mRNA, wherein the base sequence of the portion is or comprises UUGCAAGUCUGUCAUCUUUGUCUAACUUCCUA.

[0129] In some embodiments, an oligonucleotide hybridizes to two or more variants of transcripts derived from a sense strand. In some embodiments, an oligonucleotide hybridizes to two or more variants of HTT derived from the sense strand. In some embodiments, an oligonucleotide hybridizes to all valiants of HTT derived from the sense strand. In some embodiments, an oligonucleotide hybridizes to two or more variants of HTT derived from the antisense strand. In some embodiments, an oligonucleotide hybridizes to all variants of HTT derived from the antisense strand. In some embodiments, an oligonucleotide can hybridize to a HTT transcript comprises exon 2 and a HTTla transcript which does not contain exon 2.

[0130] In some embodiments, an HTT target of an oligonucleotide described herein is an HTT RNA which is not a mRNA.

[0131] In some embodiments, oligonucleotides of a plurality, e.g., in provided compositions, are of the same oligonucleotide type. In some embodiments, oligonucleotides of an oligonucleotide type have the same constitution. In some embodiments, oligonucleotides of an oligonucleotide type are identical. In some embodiments, oligonucleotides of a plurality are identical. In some embodiments, oligonucleotides of a plurality share the same constitution. In some embodiments, a non-random level of all oligonucleotides in a composition share a common base sequence and a same base and sugar modifications are oligonucleotides of a plurality. In some embodiments, each oligonucleotides of the plurality is independently a pharmaceutically acceptable salt. In some embodiments, oligonucleotides of the plurality are or comprise two or more pharmaceutically acceptable salts. In some embodiments, each chiral linkage phosphorus in the oligonucleotides of the plurality independently has a diastereomeric purity of about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%.

[0132] In some embodiments, oligonucleotides of the plurality are or comprise two or more pharmaceutically acceptable salts.

[0133] In some embodiments, each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%. In some embodiments, a chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 90%. In some embodiments, a chiral linkage phosphorus Page 49 of 20113318736vlAttorney Docket No.: 2010581-1667independently has a diastereomeric purity of about or at least about 95%. In some embodiments, a chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 98%.

[0134] In some embodiments, a level of oligonucleotides of the plurality in oligonucleotides in a composition that share the constitution of an oligonucleotide of the plurality is about or at least (DS)nc, wherein DS is about 85%-100% (e.g., about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, or about 99.5%) and nc is the number of chiral linkage phosphorus. In some embodiments, a level of an oligonucleotide in oligonucleotides in a composition that share the constitution of the oligonucleotide is about or at least (DS)nc, wherein DS is about 85%-100% (e.g., about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, or about 99.5%) and nc is the number of chiral linkage phosphorus. In some embodiments, diastereomeric purity of an oligonucleotide (e.g., with respect to chiral linkage phosphorus) in a composition is about or at least (DS)nc, wherein DS is about 85%-100% (e.g., about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, or about 99.5%) and nc is the number of chiral linkage phosphorus. In some embodiments, a DS is about or at least about 90%. In some embodiments, a DS is about or at least about 95%. In some embodiments, a DS is about or at least about 98%. In some embodiments, a DS is about or at least about 99%. In some embodiments, a level of oligonucleotides of a plurality in oligonucleotides in a composition that share the constitution of an oligonucleotide of the plurality is about or at least about 20%-100%. In some embodiments, a level of an oligonucleotide in a composition that share the constitution of the oligonucleotide is about or at least about 20%-100%. In some embodiments, diastereomeric purity of an oligonucleotide, e.g., with respect to chiral linkage phosphorus, is about or at least about 20%-100%. In some embodiments, the percentage is about or at least about 20%-95%, about 30%-90%, about 40%-85%, about 40%-80%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 75%, about 80%, about 85%, or about 90%.

[0135] In some embodiments, an oligonucleotide is a salt. In some embodiments, an oligonucleotide is a pharmaceutically acceptable salt. In some embodiments, an oligonucleotide is a sodium salt. In some embodiments, oligonucleotides of a plurality in a composition are pharmaceutically acceptable salts. In some embodiments, oligonucleotides of a plurality in a composition are each independendy a pharmaceutically acceptable salt. In some embodiments, oligonucleotides of a plurality in a composition are sodium salts. In some embodiments, oligonucleotides of a plurality in a composition are each independently a sodium salt.

[0136] In some embodiments, as exemplified herein, oligonucleotides, e.g., oligonucleotides described herein, are chiral controlled, comprising one or more chirally controlled internucleotidic linkages. In some embodiments, provided oligonucleotides are stereochemically pure. In some embodiments, provided oligonucleotides are substantially separated from other stereoisomers.

[0137] In some embodiments, oligonucleotides, e.g., oligonucleotides described herein, comprise one or more modified nucleobases, one or more modified sugars, and / or one or more modified internucleotidic Page 50 of 20113318736vlAttorney Docket No.: 2010581-1667linkages.

[0138] In some embodiments, oligonucleotides, e.g., oligonucleotides described herein, comprise one or more modified sugars. In some embodiments, oligonucleotides of the present disclosure comprise one or more modified nucleobases. Various modifications can be introduced to a sugar and / or nucleobase in accordance with the present disclosure. For example, in some embodiments, a modification is a modification described in US 9006198. In some embodiments, a modification is a modification described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, or WO 2018 / 098264, the sugar, base, and internucleotidic linkage modifications of each of which are independently incorporated herein by reference.

[0139] As used in the present disclosure, in some embodiments, one or more is one. In some embodiments, one or more is two. In some embodiments, one or more is three. In some embodiments, one or more is four. In some embodiments, one or more is five. In some embodiments, one or more is six. In some embodiments, one or more is seven. In some embodiments, one or more is eight. In some embodiments, one or more is nine. In some embodiments, one or more is ten. In some embodiments, one or more is at least one. In some embodiments, one or more is at least two. In some embodiments, one or more is at least three. In some embodiments, one or more is at least four. In some embodiments, one or more is at least five. In some embodiments, one or more is at least six. In some embodiments, one or more is at least seven. In some embodiments, one or more is at least eight. In some embodiments, one or more is at least nine. In some embodiments, one or more is at least ten.

[0140] In some embodiments, an oligonucleotide is or comprises an oligonucleotide described in Table 1.

[0141] As demonstrated in the present disclosure, in some embodiments, a provided oligonucleotide (e.g., an oligonucleotide described herein) is characterized in that, when it is contacted with the transcript in a knockdown system, knockdown of its target (e.g., an HTT transcript for an oligonucleotide, a mutant HTT transcript comprising expanded CAG repeats, a mutant HTT transcript consisting of exon 1 and parts of intron lof a HTT gene etc.) is improved relative to that observed under reference conditions (e.g., selected from the group consisting of absence of the composition, presence of a reference composition, and combinations thereof). In some embodiments, knockdown is increased about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, about 100%, or about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19, about 20, about 21, about 22, about 23, about 24, about 25, about 26, about 27, about 28, about 29, about 30, about 40, about 50, about 60, about 70, about 80, about 90, about 100, about 200, about 300, about 400, about 500, about 600, about 700, about 800, about 900, about 1000 fold or more. In some embodiments, a reference composition is WV-38221.

[0142] In some embodiments, oligonucleotides are provided as salt forms. In some embodiments,Page 51 of 20113318736vlAttorney Docket No.: 2010581-1667oligonucleotides are provided as salts comprising negatively-charged internucleotidic linkages (e.g., phosphorothioate internucleotidic linkages, natural phosphate linkages, etc.) existing as their salt forms. In some embodiments, oligonucleotides are provided as pharmaceutically acceptable salts. In some embodiments, oligonucleotides are provided as metal salts. In some embodiments, oligonucleotides are provided as sodium salts. In some embodiments, oligonucleotides are provided as metal salts, e.g., sodium salts, wherein each negatively-charged internucleotidic linkage is independently in a salt form (e.g., for sodium salts, -O-P(O)(SNa)-O- for a phosphorothioate internucleotidic linkage, -O-P(O)(ONa)-O- for a natural phosphate linkage, etc.).

[0143] In some embodiments, an oligonucleotide is a gapmer. In some embodiments, an oligonucleotide comprises 5 ’-wing-core-wing-3’. Various designs of wings and cores can be utilized in accordance with the present disclosure, e.g., those described in US 20180216108 and US 20220098585, the wings and cores of each of which are incorporated herein by reference. In some embodiments, a sugar in a 5 ’-wing is a modified sugar. In some embodiments, each sugar in a 5 ’-wing is independently a modified sugar. In some embodiments, each sugar in a 5’-wing is the same. In some embodiments, a sugar in a 3’-wing is a modified sugar. In some embodiments, each sugar in a 3’-wing is independently a modified sugar. In some embodiments, each sugar in a 3 ’-wing is the same. In some embodiments, a modified sugar is a 2’-ORw2smodified sugar or a bicyclic sugar, wherein Rw2sis optionally substituted C1-6aliphatic. In some embodiments, a modified sugar is a 2’-ORw2smodified sugar, wherein Rw2sis optionally substituted C1-6aliphatic. In some embodiments, a modified sugar is a 2’-0Me modified sugar. In some embodiments, a modified sugar is a 2’-MOE modified sugar. In some embodiments, a modified sugar is a bicyclic sugar. In some embodiments, a modified sugar in a 5’-wing is a 2’-M0E modified sugar. In some embodiments, each modified sugar in a 5’-wing is a 2’-MOE modified sugar. In some embodiments, a modified sugar in a 3’-wing is a 2’-OMe modified sugar. In some embodiments, each modified sugar in a 3’-wing is a 2’-OMe modified sugar. In some embodiments, a modified sugar in a 5’-wing is not in a 3’-wing. In some embodiments, a modified sugar in a 3 ’-wing is not in a 5 ’-wing. In some embodiments, the pattern of modified sugar in a 5 ’-wing is different from that of a 3’-wing. In some embodiments, the pattern of modified sugar in a 5’-wing is the same as that of a 3’-wing. In some embodiments, the majority of sugars in a core are natural DNA sugars. In some embodiments, each sugar in a core is a DNA sugar.

[0144] In some embodiments, each wing sugar is independently a 2’ -modified sugar. In some embodiments, at least one wing sugar is a bicyclic sugar. In some embodiments, sugar units in each wing have the same sugar modification (e.g., 2’-OMe (a 2’-OMe wing), 2’-MOE (a 2’-M0E wing), etc.). In some embodiments, each wing sugar has the same modification.

[0145] Wings and cores can have various lengths. In some embodiments, a wing is 2, 3, 4, 5, 6, 7, 8, 9, 10 or more nucleosides (in many embodiments, 3, 4, 5, or 6 or more) in length, and a core is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more nucleosides (in many embodiments, 8, 9, 10, 11, 12, or more) in length. In some embodiments, an oligonucleotide comprises or consists of a wing-core-wing structure Page 52 of 20113318736vlAttorney Docket No.: 2010581-1667of 2-9-6, 3-9-3, 3-9-4, 3-9-5, 4-7-4, 4-9-4, 4-9-5, 4-10-5, 4-11-4, 4-11-5, 5-7-5, 5-8-6, 5-9-3, 5-9-5, 5-10-4, 5-10-5, 6-7-6, 6-8-5, or 6-9-2.

[0146] Various internucleotidic linkages can be utilized in wings and cores. In some embodiments, a wing comprises a PO internucleotidic linkage. In some embodiments, a wing comprise a PS internucleotidic linkage. In some embodiments, a wing comprises a PN internucleotidic linkage. In some embodiments, a wing (e.g., a 5’-wing in an oligonucleotide in Table 1) comprises a PS internucleotidic linkage and a PN internucleotidic linkage. In some embodiments, a wing comprises (e.g., a 5’-wing in an oligonucleotide in Table 1) a PO internucleotidic linkage, a PS internucleotidic linkage and a PN internucleotidic linkage. In some embodiments, a 5 ’-wing comprises a PO internucleotidic linkage. In some embodiments, a 5 ’-wing comprises a PS internucleotidic linkage. In some embodiments, a 5 ’-wing comprises a PN internucleotidic linkage. In some embodiments, a 3 ’-wing comprises a PO internucleotidic linkage. In some embodiments, a 3 ’-wing comprises a PS internucleotidic linkage. In some embodiments, a 3 ’-wing comprises a PN internucleotidic linkage. In some embodiments, a PO internucleotidic linkage is a natural phosphate linkage. In some embodiments, each PO internucleotidic linkage is a natural phosphate linkage. In some embodiments, a PS internucleotidic linkage is a phosphorothioate internucleotidic linkage. In some embodiments, each PS internucleotidic linkage is a phosphorothioate internucleotidic linkage. In some embodiments, a PN internucleotidic linkage is a phosphoramidate linkage. In some embodiments, a PN internucleotidic linkage is a phosphoryl guanidine internucleotidic linkage. In some embodiments, a PN internucleotidic linkage is a N-(l,3-dimethylimidazolidin-2-ylidene) phosphoramidate linkage. In some embodiments, a PN internucleotidic linkage is a MePA linkage. In some embodiments, each PN internucleotidic linkage is independently a phosphoramidate linkage. In some embodiments, each PN internucleotidic linkage is independently a phosphoryl guanidine internucleotidic linkage or a MsPA linkage. In some embodiments, each PN internucleotidic linkage is independently a N-(l,3-dimethylimidazolidin-2-ylidene) phosphoramidate linkage or a MsPA linkage. In some embodiments, each internucleotidic linkage is a 2V-( 1,3-dimethylimidazolidin-2-ylidene) phosphoramidate linkage.Base Sequences

[0147] In some embodiments, an oligonucleotide, e.g., an oligonucleotide described herein, comprises a base sequence (e.g., a base sequence in Table B-l wherein each T is independently and optionally replaced with U and vice versa) described herein or a portion (e.g., a span of 5-50, 5-40, 5-30, 5-20, or 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or at least 10, at least 15, contiguous nucleobases) thereof with 0-5 (e.g., 0, 1, 2, 3, 4 or 5) mismatches. In some embodiments, an oligonucleotide, e.g., an oligonucleotide described herein, comprises a base sequence described herein (e.g., a base sequence in Table B-l wherein each T is independently and optionally replaced with U and vice versa), or a portion thereof, wherein a portion is a span of at least 10 contiguous nucleobases, or a span of at least 15 contiguous nucleobases with 1-5 mismatches. In some embodiments, provided oligonucleotides comprise a base sequence described herein (e.g., a base Page 53 of 20113318736vlAttorney Docket No.: 2010581-1667sequence in Table B-l wherein each T is independently and optionally replaced with U and vice versa), or a portion thereof, wherein a portion is a span of at least 10 contiguous nucleobases, or a span of at least 10 contiguous nucleobases with 1-5 mismatches. In some embodiments, base sequences of oligonucleotides comprise or consists of 10-50 (e.g., about or at least 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 35, 40, 45; in some embodiments, at least 15; in some embodiments, at least 16; in some embodiments, at least 17; in some embodiments, at least 18; in some embodiments, at least 19) contiguous bases of a base sequence that is identical to or complementary to a base sequence of an HTT gene or a transcript (e.g., mRNA e.g., mutant HTT RNA e.g., HTTla RNA) thereof. In some embodiments, an oligonucleotide is or comprises a base sequence in Table B-l, wherein each T is independently and optionally replaced with U and vice versa.

[0148] Base sequences of provided oligonucleotides, as appreciated by those skilled in the art, typically have sufficient length and complementarity to their targets, e.g., RNA transcripts (e.g., pre-mRNA, mature mRNA, etc.) to mediate target-specific knockdown. In some embodiments, the base sequence of an oligonucleotide has a sufficient length and identity to an HTT transcript target to mediate target-specific knockdown. In some embodiments, the oligonucleotide is complementary to a portion of an HTT transcript (a HTT transcript target sequence). In some embodiments, the base sequence of an oligonucleotide has 90% or more identity with the base sequence of an oligonucleotide disclosed in a Table (e.g., Table B-l), wherein each T is independently and optionally replaced with U and vice versa. In some embodiments, the base sequence of an oligonucleotide has 95% or more identity with the base sequence of an oligonucleotide disclosed in a Table (e.g., Table B-l), wherein each T is independently and optionally replaced with U and vice versa. In some embodiments, the base sequence of an oligonucleotide comprises a continuous span of 18 or more bases of an oligonucleotide disclosed herein, except for a difference in the 1 or 2 bases at the 5’ end and / or 3’ end of the base sequences. In some embodiments, the base sequence of an oligonucleotide comprises a continuous span of 18 or more bases of a base sequence in Table B-l, wherein each T is independently and optionally replaced with U and vice versa, except for a difference in the 1 or 2 bases at the 5’ end and / or 3’ end of the base sequences.

[0149] In some embodiments, a base sequence of an oligonucleotide is, comprises, or comprises 10-19, e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 contiguous bases of TGTGGGTCACTCTGUCUCU, wherein each T may be independently replaced with U and vice versa.

[0150] In some embodiments, a base sequence of an oligonucleotide is, comprises, or comprises 10-19, e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 contiguous bases of TTGGGTTGCTGGGUC ACU, wherein each T may be independently replaced with U and vice versa.

[0151] Certain base sequences are presented in Table B-l as examples.Table B-l. Certain Useful Base Sequences.GGGTCACTCTGTCTCUGCGG, TGGGTCACTCTGTCTCUGCG, GCTGGGTCACTCTGTCUCUG, TGCTGGGTCACTCTGUCUCU, TTGCTGGGTCACTCTGUCUC, GTTGCTGGGTCACTCUGUCU,GGTTGCTGGGTC ACTCUGUC, GGGTTGCTGGGTC ACUCUGU, TGGGTTGCTGGGTC ACUCUG,Page 54 of 20113318736vlAttorney Docket No.: 2010581-1667CTGGGTTGCTGGGTCACUCU, TCTGGGTTGCTGGGTCACUC, CTCTGGGTTGCTGGGUCACU, GCTCTGGGTTGCTGGGUCAC, CAGGCCCCAACAAGGCUCUG, ACAGGCCCCAACAAGGCUCU, GACAGGCCCCAACAAGGCUC, GGACAGGCCCCAACAAGGCU, AGGACAGGCCCCAACAAGGC, CAGGACAGGCCCCAACAAGG, TCAGGACAGGCCCCAACAAG, TTCAGGACAGGCCCCAACAA, ATTCAGGACAGGCCCCAACA, AATTCAGGACAGGCCCCAAC, GAATTCAGGACAGGCCCCAA, TTTCTCTATTGCACAUUCCC,CTCAGTAACATTGACACCACOligonucleotide Compositions

[0152] Among other things, the present disclosure provides various oligonucleotide compositions. In some embodiments, the present disclosure provides oligonucleotide compositions of oligonucleotides described herein. In some embodiments, an oligonucleotide composition comprises a plurality of oligonucleotides described in the present disclosure. In some embodiments, an oligonucleotide composition is chirally controlled. In some embodiments, an oligonucleotide composition is not chirally controlled (stereorandom).

[0153] Linkage phosphorus of natural phosphate linkages is achiral. Linkage phosphorus of many modified internucleotidic linkages, e.g., phosphorothioate internucleotidic linkages, are chiral. In some embodiments, during preparation of oligonucleotide compositions (e.g., in traditional phosphoramidite oligonucleotide synthesis), configurations of chiral linkage phosphorus are not purposefully designed or controlled, creating non-chirally controlled (stereorandom) oligonucleotide compositions (substantially racemic preparations) which are complex, random mixtures of various stereoisomers (diastereoisomers) - for oligonucleotides with n chiral internucleotidic linkages (linkage phosphorus being chiral), typically 2nstereoisomers (e.g., when n is 10, 210=1,032; when n is 20, 220= 1,048,576). These stereoisomers have the same constitution, but differ with respect to the pattern of stereochemistry of their linkage phosphorus.

[0154] In some embodiments, stereorandom oligonucleotide compositions have sufficient properties and / or activities for certain purposes and / or applications. In some embodiments, stereorandom oligonucleotide compositions can be cheaper, easier and / or simpler to produce than chirally controlled oligonucleotide compositions. However, stereoisomers within stereorandom compositions may have different properties, activities, and / or toxicities, resulting in inconsistent therapeutic effects and / or unintended side effects by stereorandom compositions, particularly compared to certain chirally controlled oligonucleotide compositions of oligonucleotides of the same constitution.

[0155] In some embodiments, the present disclosure encompasses technologies for designing and preparing chirally controlled oligonucleotide compositions. In some embodiments, the present disclosure provides chirally controlled oligonucleotide compositions, e.g., of many oligonucleotides in Table 1 which contain S and / or R in their stereochemistry / linkage. In some embodiments, a chirally controlled oligonucleotide composition comprises a controlled / pre-determined (not random as in stereorandom compositions) level of a plurality of oligonucleotides, wherein the oligonucleotides share the same linkage phosphorus stereochemistry at one or more chiral internucleotidic linkages (chirally controlled internucleotidic Page 55 of 20113318736vlAttorney Docket No.: 2010581-1667linkages). In some embodiments, the oligonucleotides share the same pattern of backbone chiral centers (stereochemistry of linkage phosphorus). In some embodiments, a pattern of backbone chiral centers is as described in the present disclosure. In some embodiments, oligonucleotides of a plurality are structural identical.

[0156] In some embodiments, oligonucleotide of a plurality share the same nucleobase modifications and / or sugar modifications. In some embodiments, oligonucleotide of a plurality share the same internucleotidic linkage modifications (wherein the internucleotidic linkages may be in various acid, base, and / or salt forms). In some embodiments, oligonucleotides of a plurality share the same nucleobase modifications, sugar modifications, and internucleotidic linkage modifications, if any. In some embodiments, oligonucleotides of a plurality are of the same form, e.g., an acid form, a base form, or a particularly salt form (e.g., a pharmaceutically acceptable salt form, e.g., salt form). In some embodiments, oligonucleotides in a composition may exist as one or more forms, e.g., acid forms, base forms, and / or one or more salt forms. In some embodiments, in an aqueous solution (e.g., when dissolved in a buffer like PBS), anions and cations may dissociate. In some embodiments, oligonucleotides of a plurality are of the same constitution. In some embodiments, oligonucleotides of a plurality are structurally identical. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein the oligonucleotides are of a common constitution, and share the same linkage phosphorus stereochemistry at one or more (e.g., 1-60, 1-50, 1-40, 1-30, 1-25, 1-20, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42. 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 or more) chiral internucleotidic linkages (chirally controlled internucleotidic linkages), wherein the composition is enriched, relative to a substantially racemic preparation of oligonucleotides of the common constitution, for oligonucleotides of the plurality.

[0157] In some embodiments, at least one chiral internucleotidic linkage is chirally controlled. In some embodiments, at least 2 internucleotidic linkages are independently chirally controlled. In some embodiments, the number of chirally controlled internucleotidic linkages is at least 3. In some embodiments, it is at least 4. In some embodiments, it is at least 5. In some embodiments, it is at least 6. In some embodiments, it is at least 7. In some embodiments, it is at least 8. In some embodiments, it is at least 9. In some embodiments, it is at least 10. In some embodiments, it is at least 11. In some embodiments, it is at least 12. In some embodiments, it is at least 13. In some embodiments, it is at least 14. In some embodiments, it is at least 15. In some embodiments, it is at least 20. In some embodiments, it is at least 25. In some embodiments, it is at least 30.

[0158] In some embodiments, at least 5%-100% (e.g., about 10%-100%, 20-100%, 30%-100%, 40%-100%, 50%-80%, 50%-85%, 50%-90%, 50%-95%, 60%-80%, 60%-85%, 60%-90%, 60%-95%, 60%-100%, 65%-80%, 65%-85%, 65%-90%, 65%-95%, 65%-100%, 70%-80%, 70%-85%, 70%-90%, 70%-95%, 70%-100%, 75%-80%, 75%-85%, 75%-90%, 75%-95%, 75%-100%, 80%-85%, 80%-90%, 80%-95%, 80%-100%,Page 56 of 20113318736vlAttorney Docket No.: 2010581-166785%-90%, 85%-95%, 85%-100%, 90%-95%, 90%-100%, 10%, 20%, 30%, 40%, 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, etc.) of all internucleotidic linkages are chirally controlled. In some embodiments, at least 5%-100% (e.g., about 10%-100%, 20-100%, 30%-100%, 40%-100%, 50%-80%, 50%-85%, 50%-90%, 50%-95%, 60%-80%, 60%-85%, 60%-90%, 60%-95%, 60%-100%, 65%-80%, 65%-85%, 65%-90%, 65%-95%, 65%-100%, 70%-80%, 70%-85%, 70%-90%, 70%-95%, 70%-100%, 75%-80%, 75%-85%, 75%-90%, 75%-95%, 75%-100%, 80%-85%, 80%-90%, 80%-95%, 80%-100%, 85%-90%, 85%-95%, 85%-100%, 90%-95%, 90%-100%, 10%, 20%, 30%, 40%, 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, etc.) of all chiral internucleotidic linkages are chirally controlled. In some embodiments, at least 5%-100% (e.g., about 10%-100%, 20-100%, 30%-100%, 40%-100%, 50%-80%, 50%-85%, 50%-90%, 50%-95%, 60%-80%, 60%-85%, 60%-90%, 60%-95%, 60%-100%, 65%-80%, 65%-85%, 65%-90%, 65%-95%, 65%-100%, 70%-80%, 70%-85%, 70%-90%, 70%-95%, 70%-100%, 75%-80%, 75%-85%, 75%-90%, 75%-95%, 75%-100%, 80%-85%, 80%-90%, 80%-95%, 80%-100%, 85%-90%, 85%-95%, 85%-100%, 90%-95%, 90%-100%, 10%, 20%, 30%, 40%, 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, etc.) of all phosphorothioate internucleotidic linkages are chirally controlled. In some embodiments, a percentage is at least 50%. In some embodiments, a percentage is at least 60%. In some embodiments, a percentage is at least 70%. In some embodiments, a percentage is at least 80%. In some embodiments, a percentage is at least 90%. In some embodiments, a percentage is at least 90%. In some embodiments, each chiral internucleotidic linkage is chirally controlled. In some embodiments, each phosphorothioate internucleotidic linkage is chirally controlled.

[0159] In some embodiments, no more than 1-10, e.g., no more than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, chiral internucleotidic linkages are not chirally controlled. In some embodiments, no more than 1 chiral internucleotidic linkages is not chirally controlled, In some embodiments, no more than 2 chiral internucleotidic linkages are not chirally controlled, In some embodiments, no more than 3 chiral internucleotidic linkages are not chirally controlled, In some embodiments, no more than 4 chiral internucleotidic linkages are not chirally controlled. In some embodiments, no more than 5 chiral internucleotidic linkages are not chirally controlled. In some embodiments, the number of non-chirally controlled internucleotidic linkages is 1. In some embodiments, it is 2. In some embodiments, it is 3. In some embodiments, it is 4. In some embodiments, it is 5.

[0160] In some embodiments, the present disclosure provides a composition comprising a plurality of oligonucleotides, wherein each oligonucleotide of the plurality is independently a particular oligonucleotide or a salt thereof. In some embodiments, the present disclosure provides a composition comprising a plurality of oligonucleotides, wherein each oligonucleotide of the plurality is independently a particular oligonucleotide or a pharmaceutically acceptable salt thereof. In some embodiments, such a composition is enriched relative to a substantially racemic preparation of a particular oligonucleotide. As appreciated by those skilled in the art, oligonucleotides of the plurality share a common sequence which is the base sequence of the particular oligonucleotide. In some embodiments, at least about 5%-100%, 10%-100%, 20-100%, 30%-100%, 40%- Page 57 of 20113318736vlAttorney Docket No.: 2010581-1667100%, 50%-100%, 5%-90%, 10%-90%, 20-90%, 30%-90%, 40%-90%, 50%-90%, 5%-85%, 10%-85%, 20-85%, 30%-85%, 40%-85%, 50%-85%, 5%-80%, 10%-80%, 20-80%, 30%-80%, 40%-80%, 50%-80%, 5%-75%, 10%-75%, 20-75%, 30%-75%, 40%-75%, 50%-75%, 5%-70%, 10%-70%, 20-70%, 30%-70%, 40%-70%, 50%-70%, 5%-65%, 10%-65%, 20-65%, 30%-65%, 40%-65%, 50%-65%, 5%-60%, 10%-60%, 20-60%, 30%-60%, 40%-60%, 50%-60%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of all oligonucleotides in the composition that share the base sequence of a the particular oligonucleotide are oligonucleotide of the plurality. In some embodiments, at least about 5%-100%, 10%-100%, 20-100%, 30%-100%, 40%-100%, 50%-100%, 5%-90%, 10%-90%, 20-90%, 30%-90%, 40%-90%, 50%-90%, 5%-85%, 10%-85%, 20-85%, 30%-85%, 40%-85%, 50%-85%, 5%-80%, 10%-80%, 20-80%, 30%-80%, 40%-80%, 50%-80%, 5%-75%, 10%-75%, 20-75%, 30%-75%, 40%-75%, 50%-75%, 5%-70%, 10%-70%, 20-70%, 30%-70%, 40%-70%, 50%-70%, 5%-65%, 10%-65%, 20-65%, 30%-65%, 40%-65%, 50%-65%, 5%-60%, 10%-60%, 20-60%, 30%-60%, 40%-60%, 50%-60%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of all oligonucleotides in the composition that share the constitution of the particular oligonucleotide or a salt thereof are oligonucleotide of the plurality. In some embodiments, a percentage is at least 10%. In some embodiments, a percentage is at least 20%. In some embodiments, a percentage is at least 30%. In some embodiments, a percentage is at least 40%. In some embodiments, a percentage is at least 50%. In some embodiments, it is at least 60%. In some embodiments, it is at least 70%. In some embodiments, it is at least 80%. In some embodiments, it is at least 90%. In some embodiments, it is at least 95%. In some embodiments, it is about 5-100%. In some embodiments, it is about 10-100%. In some embodiments, it is about 20-100%. In some embodiments, it is about 30-90%. In some embodiments, it is about 30-80%. In some embodiments, it is about 30-70%. In some embodiments, it is about 40-90%. In some embodiments, it is about 40-80%. In some embodiments, it is about 40-70%. In some embodiments, a particular oligonucleotide is an oligonucleotide exemplified herein, e.g., an oligonucleotide of Table 1 or another table.

[0161] In some embodiments, an enrichment relative to a substantially racemic preparation is that at least about 5%-100%, 10%-100%, 20-100%, 30%-100%, 40%-100%, 50%-100%, 5%-90%, 10%-90%, 20-90%, 30%-90%, 40%-90%, 50%-90%, 5%-85%, 10%-85%, 20-85%, 30%-85%, 40%-85%, 50%-85%, 5%-80%, 10%-80%, 20-80%, 30%-80%, 40%-80%, 50%-80%, 5%-75%, 10%-75%, 20-75%, 30%-75%, 40%-75%, 50%-75%, 5%-70%, 10%-70%, 20-70%, 30%-70%, 40%-70%, 50%-70%, 5%-65%, 10%-65%, 20-65%, 30%-65%, 40%-65%, 50%-65%, 5%-60%, 10%-60%, 20-60%, 30%-60%, 40%-60%, 50%-60%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of all oligonucleotides in the composition, or all oligonucleotides in the composition that share the common base sequence of a plurality, or all oligonucleotides in the composition that share the common constitution of a plurality, are oligonucleotide of the plurality. In some embodiments, a percentage is at least 10%. In some embodiments, a percentage is at least 20%. In some embodiments, a percentage is at least 30%. In some embodiments, a percentage is at least 40%. In some embodiments, a percentage is at least 50%. In some Page 58 of 20113318736vlAttorney Docket No.: 2010581-1667embodiments, it is at least 60%. In some embodiments, it is at least 70%. In some embodiments, it is at least 80%. In some embodiments, it is at least 90%. In some embodiments, it is at least 95%. In some embodiments, it is about 5-100%. In some embodiments, it is about 10-100%. In some embodiments, it is about 20-100%. In some embodiments, it is about 30-90%. In some embodiments, it is about 30-80%. In some embodiments, it is about 30-70%. In some embodiments, it is about 40-90%. In some embodiments, it is about 40-80%. In some embodiments, it is about 40-70%.

[0162] In some embodiments, at least about 5%-100%, 10%-100%, 20-100%, 30%-100%, 40%-100%, 50%-100%, 5%-90%, 10%-90%, 20-90%, 30%-90%, 40%-90%, 50%-90%, 5%-85%, 10%-85%, 20-85%, 30%-85%, 40%-85%, 50%-85%, 5%-80%, 10%-80%, 20-80%, 30%-80%, 40%-80%, 50%-80%, 5%-75%, 10%-75%, 20-75%, 30%-75%, 40%-75%, 50%-75%, 5%-70%, 10%-70%, 20-70%, 30%-70%, 40%-70%, 50%-70%, 5%-65%, 10%-65%, 20-65%, 30%-65%, 40%-65%, 50%-65%, 5%-60%, 10%-60%, 20-60%, 30%-60%, 40%-60%, 50%-60%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% of all oligonucleotides in the composition that share the common base sequence of a plurality are oligonucleotide of the plurality. In some embodiments, a percentage is at least 10%. In some embodiments, a percentage is at least 20%. In some embodiments, a percentage is at least 30%. In some embodiments, a percentage is at least 40%. In some embodiments, a percentage is at least 50%. In some embodiments, it is at least 60%. In some embodiments, it is at least 70%. In some embodiments, it is at least 80%. In some embodiments, it is at least 90%. In some embodiments, it is at least 95%. In some embodiments, it is about 5-100%. In some embodiments, it is about 10-100%. In some embodiments, it is about 20-100%. In some embodiments, it is about 30-90%. In some embodiments, it is about 30-80%. In some embodiments, it is about 30-70%. In some embodiments, it is about 40-90%. In some embodiments, it is about 40-80%. In some embodiments, it is about 40-70%.

[0163] Levels of oligonucleotides of a plurality in chirally controlled oligonucleotide compositions are controlled. In contrast, in non-chirally controlled (or stereorandom, racemic) oligonucleotide compositions (or preparations), levels of oligonucleotides are random and not controlled. In some embodiments, an enrichment relative to a substantially racemic preparation is a level described herein.

[0164] In some embodiments, a level as a percentage (e.g., a controlled level, a pre-determined level, an enrichment) is or is at least (DS)nc, wherein DS (diastereopurity of an individual internucleotidic linkage) is 90%-100%, and nc is the number of chiral linkage phosphorus as described in the present disclosure (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more). In some embodiments, a level as a percentage (e.g., a controlled level, a pre-determined level, an enrichment) is or is at least (DS)nc, wherein DS (diastereopurity of an individual internucleotidic linkage) is 90%-100%, and nc is the number of chirally controlled internucleotidic linkages as described in the present disclosure (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more). In some embodiments, each chiral internucleotidic linkage is chirally controlled, and nc is the number of chiral internucleotidic linkage. In some embodiments, DS is 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% or more. In some embodiments, DS is or is at least Page 59 of 20113318736vlAttorney Docket No.: 2010581-166790%. In some embodiments, DS is or is at least 91%. In some embodiments, DS is or is at least 92%. In some embodiments, DS is or is at least 93%. In some embodiments, DS is or is at least 94%. In some embodiments, DS is or is at least 95%. In some embodiments, DS is or is at least 96%. In some embodiments, DS is or is at least 97%. In some embodiments, DS is or is at least 98%. In some embodiments, DS is or is at least 99%. In some embodiments, a level (e.g., a controlled level, a pre-determined level, an enrichment) is a percentage of all oligonucleotides in a composition that share the same constitution, wherein the percentage is or is at least (DS)nc. For example, when DS is 99% and nc is 10, the percentage is or is at least 90% ((99%)10≈ 0.90 = 90%). As appreciated by those skilled in the art, in a stereorandom preparation the percentage is typically about l / 2nc- when nc is 10, the percentage is about 1 / 2100.001 = 0.1%. In some embodiments, an enrichment (e.g., relative to a substantially racemic preparation), a level, etc., is that at least about (DS)ncof all oligonucleotides in the composition, or all oligonucleotides in the composition that share the common base sequence of a plurality, or all oligonucleotides in the composition that share the common constitution of a plurality, are oligonucleotide of the plurality. In some embodiments, it is of all oligonucleotides in the composition. In some embodiments, it is of all oligonucleotides in the composition that share the common base sequence of a plurality. In some embodiments, it is of all oligonucleotides in the composition that share the common constitution of a plurality. In some embodiments, various forms (e.g., various salt forms) of an oligonucleotide may be properly considered to have the same constitution.

[0165] In some embodiments, oligonucleotides comprise one or more (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more) chirally controlled chiral internucleotidic linkages the diastereomeric excess (d.e.) of whose linkage phosphorus is independently about or at least about 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99%. In some embodiments, about or at least about 50%, 60%, 70%, 75%, 80%, 85%, 90%, or 95% of all chiral internucleotidic linkages comprising a chiral linkage phosphorus are independently such a chirally controlled internucleotidic linkage. In some embodiments, about or at least about 50%, 60%, 70%, 75%, 80%, 85%, 90%, or 95% of phosphorothioate internucleotidic linkages are independently such a chirally controlled internucleotidic linkage. In some embodiments, each phosphorothioate internucleotidic linkage is independently such a chirally controlled internucleotidic linkage. In some embodiments, each chiral internucleotidic linkage comprising a chiral linkage phosphorus is independently such a chirally controlled internucleotidic linkage. In some embodiments, d.e. is about or at least about 80%. In some embodiments, d.e. is about or at least about 85%. In some embodiments, d.e. is about or at least about 90%. In some embodiments, d.e. is about or at least about 95%. In some embodiments, d.e. is about or at least about 96%. In some embodiments, d.e. is about or at least about 97%. In some embodiments, d.e. is about or at least about 98%.

[0166] In some embodiments, a chirally controlled oligonucleotide composition comprises two or more pluralities of oligonucleotides, wherein each plurality is independently a plurality of oligonucleotides as described herein (e.g., in various chirally controlled oligonucleotide compositions). For example, in somePage 60 of 20113318736vlAttorney Docket No.: 2010581-1667embodiments, each plurality independently shares a common base sequence, and the same linkage phosphorus stereochemistry at one or more chiral internucleotidic linkages, and each plurality is independently enriched compared to stereorandom preparation of that plurality or each plurality is independently of a level as described herein.

[0167] In some embodiments, all chiral internucleotidic linkages are chiral controlled, and the composition is a completely chirally controlled oligonucleotide composition. In some embodiments, not all chiral internucleotidic linkages are chiral controlled internucleotidic linkages, and the composition is a partially chirally controlled oligonucleotide composition.

[0168] Oligonucleotides may comprise or consist of various patterns of backbone chiral centers (patterns of stereochemistry of chiral linkage phosphorus). Certain useful patterns of backbone chiral centers are described in the present disclosure. In some embodiments, a plurality of oligonucleotides share a common pattern of backbone chiral centers, which is or comprises a pattern described in the present disclosure (e.g., as in “Linkage Phosphorus Stereochemistry and Patterns Thereof’, a pattern of backbone chiral centers of a chirally controlled oligonucleotide in Table 1, etc.).

[0169] In some embodiments, a chirally controlled oligonucleotide composition is a chirally pure (or stereopure, stereochemically pure) oligonucleotide composition, wherein the oligonucleotide composition comprises a plurality of oligonucleotides, wherein the oligonucleotides are identical [including that each chiral element of the oligonucleotides, including each chiral linkage phosphorus, is independently defined (stereodefined)], and the composition does not contain other stereoisomers. A chirally pure (or stereopure, stereochemically pure) oligonucleotide composition of an oligonucleotide stereoisomer does not contain other stereoisomers (as appreciated by those skilled in the art, one or more unintended stereoisomers may exist as impurities).

[0170] Chirally controlled oligonucleotide compositions can demonstrate a number of advantages over stereorandom oligonucleotide compositions. Among other things, chirally controlled oligonucleotide compositions are more uniform than corresponding stereorandom oligonucleotide compositions with respect to oligonucleotide structures. By controlling stereochemistry, compositions of individual stereoisomers can be prepared and assessed, so that chirally controlled oligonucleotide composition of stereoisomers with desired properties and / or activities can be developed. In some embodiments, chirally controlled oligonucleotide compositions provides better delivery, stability, clearance, activity, selectivity, and / or toxicity profiles compared to, e.g., corresponding stereorandom oligonucleotide compositions. In some embodiments, chirally controlled oligonucleotide compositions provide better efficacy, fewer side effects, and / or more convenient and effective dosage regimens. Among other tilings, patterns of backbone chiral centers as described herein optionally combined with other structural features described herein, e.g., modifications of nucleobases, sugars, internucleotidic linkages, etc. can be utilized to direct a decrease in the expression, level and / or activity of an HTT target gene or a product thereof (e.g., a mutant HTT target gene or a product thereof).

[0171] In some embodiments, an oligonucleotide composition comprises one or more internucleotidic Page 61 of 20113318736vlAttorney Docket No.: 2010581-1667linkages which are stereocontrolled (chirally controlled; in some embodiments, stereopure) and one or more internucleotidic linkages which are stereorandom. In some embodiments, an oligonucleotide composition comprises one or more internucleotidic linkages which are stereocontrolled (chirally controlled; in some embodiments, stereopure) and one or more internucleotidic linkages which are stereorandom.

[0172] In some embodiments, an oligonucleotide composition comprises one or more internucleotidic linkages which are stereocontrolled (e.g., chirally controlled or stereopure) and one or more internucleotidic linkages which are stereorandom.

[0173] In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition. In some embodiments, provided chirally controlled oligonucleotide compositions comprise a plurality of oligonucleotides of the same constitution, and have one or more internucleotidic linkages. In some embodiments, a plurality of oligonucleotides, e.g., in a chirally controlled oligonucleotide composition, is a plurality of an oligonucleotide selected from Table 1 (and / or one or more of various salts forms thereof), wherein the oligonucleotide comprises at least one Rp or Sp linkage phosphorus in a chirally controlled internucleotidic linkage. In some embodiments, a plurality of oligonucleotides, e.g., in a chirally controlled oligonucleotide composition, is a plurality of an oligonucleotide selected from Table 1 (and / or one or more of various salts forms thereof), wherein each phosphorothioate internucleotidic linkage in the oligonucleotide is independently chirally controlled (each phosphorothioate internucleotidic linkage is independently Rp or Sp ). In some embodiments, an oligonucleotide composition, e.g., an oligonucleotide composition is a substantially pure preparation of a single oligonucleotide in that oligonucleotides in the composition that are not the single oligonucleotide are impurities from the preparation process of the single oligonucleotide, in some case, after certain purification procedures. In some embodiments, a single oligonucleotide is an oligonucleotide of Table 1, wherein each chiral internucleotidic linkage of the oligonucleotide is chirally controlled.

[0174] Certain data showing properties and / or activities of chirally controlled oligonucleotide composition, e.g., chirally controlled oligonucleotide composition in modulating level, activity and / or expression of target genes and / or products thereof, are shown in, for example, the Examples of this disclosure.

[0175] In some embodiments, the present disclosure provides an oligonucleotide composition comprising oligonucleotides that comprise at least one chiral linkage phosphorus. In some embodiments, the present disclosure provides an oligonucleotide composition comprising oligonucleotides that comprise at least one chiral linkage phosphorus. In some embodiments, the present disclosure provides an oligonucleotide composition in which the oligonucleotides comprise a chirally controlled phosphorothioate internucleotidic linkage, wherein the linkage phosphorus has a Rp configuration. In some embodiments, the present disclosure provides an oligonucleotide composition in which the oligonucleotides comprise a chirally controlled phosphorothioate internucleotidic linkage, wherein the linkage phosphorus has a Sp configuration. In some embodiments, the present disclosure provides an oligonucleotide composition in which the oligonucleotides comprise a chirally controlled phosphorothioate internucleotidic linkage, wherein the linkage phosphorus has a Rp configuration and the linkage phosphorus has a Sp configuration. In some embodiments, such Page 62 of 20113318736vlAttorney Docket No.: 2010581-1667oligonucleotide compositions are chirally controlled, and the Rp and / or Sp internucleotidic linkages are independently chirally controlled internucleotidic linkages.

[0176] In some embodiments, compared to reference oligonucleotides or oligonucleotide compositions, provided oligonucleotides or oligonucleotide compositions (e.g., chirally controlled oligonucleotide compositions) are surprisingly effective. In some embodiments, desired biological effects (e.g., as measured by increased (if increase is desired) and / or decreased (if decrease is desired) levels of mRNA, proteins, etc. whose levels are targeted for increase) can be enhanced by more than 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, 50, or 100 fold (e.g., as measured by levels of desired mRNA, proteins, etc.). In some embodiments, a change is measured by increase of desired mRNA and / or protein levels, or decrease of undesired mRNA and / or protein levels, compared to a reference condition. In some embodiments, a change is measured by increase of a desired mRNA and / or protein level compared to a reference condition. In some embodiments, a change is measured by decrease of an undesired mRNA and / or level compared to a reference condition. In some embodiments, a reference condition is absence of provided oligonucleotides or oligonucleotide compositions, and or presence of reference oligonucleotides or oligonucleotide compositions, respectively. In some embodiments, a reference oligonucleotide shares the same base sequence, but different nucleobase modifications, sugar modifications, internucleotidic linkages modifications, and / or linkage phosphorus stereochemistry. In some embodiments, a reference oligonucleotide composition is a composition of oligonucleotides of the same base sequence, but different nucleobase modifications, sugar modifications, internucleotidic linkages modifications, and / or linkage phosphorus stereochemistry. In some embodiments, a reference composition for a chirally controlled oligonucleotide composition is a corresponding stereorandom composition of oligonucleotides having the same base sequence, nucleobase modifications, sugar modifications, and / or internucleotidic linkages modifications (but lack of and / or low levels of linkage phosphorus stereochemistry control), or having the same constitution.

[0177] In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, wherein the linkage phosphorus of at least one chirally controlled internucleotidic linkage is Sp. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, wherein the majority of linkage phosphorus of chirally controlled internucleotidic linkages are Sp. In some embodiments, about 50%-100%, 55%-100%, 60%-100%, 65%-100%, 70%-100%, 75%-100%, 80%-100%, 85%-100%, 90%-100%, 55%-95%, 60%-95%, 65%-95%, or about 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or more, of all chirally controlled internucleotidic linkages (or of all chiral internucleotidic linkages, or of all internucleotidic linkages) are Sp. In some embodiments, about 50%-100%, 55%-100%, 60%-100%, 65%-100%, 70%-100%, 75%-100%, 80%-100%, 85%-100%, 90%-100%, 55%-95%, 60%-95%, 65%-95%, or about 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or more, of all chirally controlled phosphorothioate internucleotidic linkages are Sp. In some embodiments, no more than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 of phosphorothioate internucleotidic linkages are non-chirally controlled or are chirally controlled and Rp. In some embodiments, no more than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 of Page 63 of 20113318736vlAttorney Docket No.: 2010581-1667phosphorothioate internucleotidic linkages are chirally controlled and Rp. In some embodiments, it is no more than 1. In some embodiments, it is no more than 2. In some embodiments, it is no more than 3. In some embodiments, it is no more than 4. In some embodiments, it is no more than 5. In some embodiments, each phosphorothioate internucleotidic linkage is independently chirally controlled. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, wherein the majority of chiral internucleotidic linkages are chirally controlled and are Sp at their linkage phosphorus. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, wherein each chiral internucleotidic linkage is chirally controlled and each chiral linkage phosphorus is Sp. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, e.g., chirally controlled oligonucleotide composition, wherein at least one chirally controlled internucleotidic linkage has a Rp linkage phosphorus. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, wherein at least one chirally controlled internucleotidic linkage comprises a Rp linkage phosphorus and at least one chirally controlled internucleotidic linkage comprises a Sp linkage phosphorus.

[0178] In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, wherein at least two chirally controlled internucleotidic linkages have different linkage phosphorus stereochemistry and / or different P-modifications relative to one another, wherein a P-modification is a modification at a linkage phosphorus. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, wherein at least two chirally controlled internucleotidic linkages have different stereochemistry relative to one another, and the pattern of the backbone chiral centers of the oligonucleotides is characterized by a repeating pattern of alternating stereochemistry.

[0179] In certain embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein with in each of the oligonucleotides at least two individual internucleotidic linkages have different P-modifications relative to one another. In certain embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein with in each of the oligonucleotides at least two individual internucleotidic linkages have different P-modifications relative to one another, and each of the oligonucleotide comprises a natural phosphate linkage. In certain embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein with in each of the oligonucleotides at least two individual internucleotidic linkages have different P-modifications relative to one another, and each of the oligonucleotide comprises a phosphorothioate internucleotidic linkage. In certain embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein widi in each of the oligonucleotides at least two individual internucleotidic linkages have different P-modifications relative to one another, and each of the oligonucleotide comprises a natural phosphate linkage and a phosphorothioate internucleotidic linkage. In certain embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein with in each of the oligonucleotides at least two individual Page 64 of 20113318736vlAttorney Docket No.: 2010581-1667internucleotidic linkages have different P-modifications relative to one another, and each of the oligonucleotide comprises a phosphorothioate triester internucleotidic linkage. In certain embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein with in each of the oligonucleotides at least two individual internucleotidic linkages have different P-modifications relative to one another, and each of the oligonucleotide comprises a natural phosphate linkage and a phosphorothioate triester internucleotidic linkage. In certain embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein with in each of the oligonucleotides at least two individual internucleotidic linkages have different P-modifications relative to one another, and each of the oligonucleotide comprises a phosphorothioate internucleotidic linkage and a phosphorothioate triester internucleotidic linkage.

[0180] In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition, comprising a plurality of oligonucleotides which share a common base sequence that is the base sequence of an oligonucleotide disclosed herein, wherein at least one internucleotidic linkage is chirally controlled.Linkage Phosphorus Stereochemistry and Pattern of Backbone Chiral Centers

[0181] Among other things, the present disclosure provides various oligonucleotide compositions. In some embodiments, the present disclosure provides oligonucleotide compositions of oligonucleotides described herein. In some embodiments, an oligonucleotide composition comprises a plurality of oligonucleotides described in the present disclosure. In some embodiments, an oligonucleotide composition is chirally controlled. In some embodiments, an oligonucleotide composition is not chirally controlled (stereorandom).

[0182] In contrast to natural phosphate linkages, linkage phosphorus of chiral modified internucleotidic linkages, e.g., phosphorothioate internucleotidic linkages, are chiral. Among other things, the present disclosure provides technologies (e.g., oligonucleotides, compositions, methods, etc.) comprising control of stereochemistry of chiral linkage phosphorus in chiral internucleotidic linkages. In some embodiments, as demonstrated herein, control of stereochemistry can provide improved properties and / or activities, including desired stability, reduced toxicity, improved modification of target nucleic acids, improved modulation of levels of transcripts and / or products (e.g., mRNA, proteins, etc.) encoded thereof, etc. In some embodiments, the present disclosure provides useful patterns of backbone chiral centers for oligonucleotides and / or regions thereof, which pattern includes a combination of stereochemistry of each chiral linkage phosphorus (Rp or Sp) of chiral linkage phosphorus, indication of each achiral linkage phosphorus (Op, if any), etc. from 5’ to 3’.

[0183] In some embodiments, an oligonucleotide or a portion thereof (e.g., a core) comprises one or more RpSpSp. In some embodiments, a core comprises one or more RpSpRp. In some embodiments, an oligonucleotide or a portion thereof (e.g., a core) comprises one or more SpRp(Sp)t, wherein each t is independently 2 or more. In some embodiments, a core comprises one or more SpRp(Sp)t, wherein each t is Page 65 of 20113318736vlAttorney Docket No.: 2010581-1667independently 2 or more. In some embodiments, each t is independently 2-10 (e.g., 2-5, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.). In some embodiments, each Rp and Sp is independently configuration of linkage phosphorus in a PS internucleotidic linkage. In some embodiments, each Rp and Sp is independently configuration of linkage phosphorus in a phosphorothioate internucleotidic linkage. In some embodiments, each Rp phosphorothioate internucleotidic linkage is in a core. In some embodiments, each linkage phosphorus of the SpRp(Sp)t is independently of a phosphorothioate internucleotidic linkage and is independently bonded to at least one sugar in a core. In some embodiments, each linkage phosphorus of the SpRp(Sp)t is independently of a phosphorothioate internucleotidic linkage and is independently bonded to at least one natural DNA sugar.

[0184] In some embodiments, each PN internucleotidic linkage is independently Rp. In some embodiments, each PN internucleotidic linkage is independently Rp.

[0185] In some embodiments, a number of linkage phosphorus in chirally controlled internucleotidic linkages are Sp. In some embodiments, at least 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of chirally controlled internucleotidic linkages have Sp linkage phosphorus. In some embodiments, at least 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of all chiral internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of all internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of all phosphorothioate internucleotidic linkages have Sp linkage phosphorus. In some embodiments, the percentage is at least 20%. In some embodiments, the percentage is at least 30%. In some embodiments, the percentage is at least 40%. In some embodiments, the percentage is at least 50%. In some embodiments, the percentage is at least 60%. In some embodiments, the percentage is at least 65%. In some embodiments, the percentage is at least 70%. In some embodiments, the percentage is at least 75%. In some embodiments, the percentage is at least 80%. In some embodiments, the percentage is at least 90%. In some embodiments, the percentage is at least 95%. In some embodiments, all chirally controlled internucleotidic linkages have Sp linkage phosphorus. In some embodiments, all chirally controlled phosphorothioate internucleotidic linkages have Sp linkage phosphorus. In some embodiments, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 5 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 6 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 7 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 8 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 9 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 10Page 66 of 20113318736vlAttorney Docket No.: 2010581-1667internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 11 internucleotidic linkages are chirally control led internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 12 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 13 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 14 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 15 internucleotidic linkages are chirally controlled internucleotidic linkages having Sp linkage phosphorus. In some embodiments, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 internucleotidic linkages are chirally controlled internucleotidic linkages having Rp linkage phosphorus. In some embodiments, no more than 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 internucleotidic linkages are chirally controlled internucleotidic linkages having ftp linkage phosphorus. In some embodiments, one and no more than one internucleotidic linkage in an oligonucleotide is a chirally controlled i nternucleotidic linkage having ftp linkage phosphorus. In some embodiments, 2 and no more than 2 internucleotidic linkages in an oligonucleotide are chirally controlled internucleotidic linkages having ftp linkage phosphorus. In some embodiments, 3 and no more than 3 internucleotidic linkages in an oligonucleotide are chirally controlled internucleotidic linkages having ftp linkage phosphorus. In some embodiments, 4 and no more than 4 internucleotidic linkages in an oligonucleotide are chirally controlled internucleotidic linkages having ftp linkage phosphorus. In some embodiments, 5 and no more than 5 internucleotidic linkages in an oligonucleotide are chirally controlled internucleotidic linkages having ftp linkage phosphorus.

[0186] In some embodiments, all, essentially all or most of the internucleotidic linkages in an oligonucleotide or a portion thereof are in the Sp configuration (e.g., about 50%-100%, 55%-100%, 60%-100%, 65%-100%, 70%-100%, 75%-100%, 80%-100%, 85%-100%, 90%-100%, 55%-95%, 60%-95%, 65%-95%, or about 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 99% or more of all chirally controlled internucleotidic linkages, or of all chiral internucleotidic linkages, or of all internucleotidic linkages in an oligonucleotide) except for one or a minority of internucleotidic linkages (e.g., 1, 2, 3, 4, or 5, and / or less than 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, or 5% of all chirally controlled internucleotidic linkages, or of all chiral internucleotidic linkages, or of all internucleotidic linkages in an oligonucleotide) being in the ftp configuration.

[0187] In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition wherein the composition comprises a non-random or controlled level of a plurality of oligonucleotides, wherein oligonucleotides of the plurality share a common base sequence, and share the same configuration of linkage phosphorus independently at 1-60, 1-50, 1-40, 1-30, 1-25, 1-20, 1-15, 1-10, 5-50, 5-40, 5-30, 5-25, 5-20, 5-15, 5-10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 or more chiral internucleotidic linkages.Page 67 of 20113318736vlAttorney Docket No.: 2010581-1667

[0188] In some embodiments, provided oligonucleotides comprise 2-30 chirally controlled internucleotidic linkages. In some embodiments, provided oligonucleotide compositions comprise 5-30 chirally controlled internucleotidic linkages. In some embodiments, provided oligonucleotide compositions comprise 10-30 chirally controlled internucleotidic linkages. In some embodiments, provided oligonucleotide compositions comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 or more chirally controlled internucleotidic linkages.

[0189] In some embodiments, about 1-100% of all internucleotidic linkages are chirally controlled internucleotidic linkages. In some embodiments, about 1-100% of all chiral internucleotidic linkages are chirally controlled internucleotidic linkages. In some embodiments, a percentage is about 5%-100%. In some embodiments, a percentage is at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 96%, 98%, or 99%. In some embodiments, a percentage is about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 96%, 98%, or 99%.

[0190] In some embodiments, an internucleotidic linkage in the Sp configuration (having a Sp linkage phosphorus) is a phosphorothioate internucleotidic linkage. In some embodiments, an achiral internucleotidic linkage is a natural phosphate linkage. In some embodiments, an internucleotidic linkage in the Rp configuration (having a Rp linkage phosphorus) is a phosphorothioate internucleotidic linkage. In some embodiments, each internucleotidic linkage in the Sp configuration is a phosphorothioate internucleotidic linkage. In some embodiments, each achiral internucleotidic linkage is a natural phosphate linkage. In some embodiments, each internucleotidic linkage in the 7?p configuration is a phosphorothioate internucleotidic linkage. In some embodiments, each internucleotidic linkage in the Sp configuration is a phosphorothioate internucleotidic linkage, each achiral internucleotidic linkage is a natural phosphate linkage, and each internucleotidic linkage in the Rp configuration is a phosphorothioate internucleotidic linkage.

[0191] In some embodiments, provided oligonucleotides in chirally controlled oligonucleotide compositions each comprise different types of internucleotidic linkages. In some embodiments, provided oligonucleotides comprise at least one natural phosphate linkage and at least one modified internucleotidic linkage. In some embodiments, provided oligonucleotides comprise at least one natural phosphate linkage and 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40 modified internucleotidic linkages. In some embodiments, a modified internucleotidic linkage is a phosphorothioate internucleotidic linkage. In some embodiments, each modified internucleotidic linkage is a phosphorothioate internucleotidic linkage. In some embodiments, each modified internucleotidic linkage is independently a chiral internucleotidic linkage and is independently chirally controlled.

[0192] In some embodiments, oligonucleotides in a chirally controlled oligonucleotide composition each comprise at least two internucleotidic linkages that have different stereochemistry and / or different P-modifications relative to one another. In some embodiments, at least two internucleotidic linkages have Page 68 of 20113318736vlAttorney Docket No.: 2010581-1667different stereochemistry relative to one another. In some embodiments, oligonucleotides each comprise a pattern of backbone chiral centers comprising alternating linkage phosphorus stereochemistry.

[0193] In some embodiments, a phosphorothioate triester linkage comprises a chiral auxiliary, which, for example, is used to control the stereoselectivity of a reaction, e.g., a coupling reaction in an oligonucleotide synthesis cycle. In some embodiments, a phosphorothioate triester linkage does not comprise a chiral auxiliary. In some embodiments, a phosphorothioate triester linkage is intentionally maintained until and / or during the administration of the oligonucleotide composition to a subject.

[0194] In some embodiments, oligonucleotides are linked to a solid support. In some embodiments, a solid support is a support for oligonucleotide synthesis. In some embodiments, a solid support comprises glass. In some embodiments, a solid support is CPG (controlled pore glass). In some embodiments, a solid support is polymer. In some embodiments, a solid support is polystyrene. In some embodiments, the solid support is Highly Crosslinked Polystyrene (HCP). In some embodiments, the solid support is hybrid support of Controlled Pore Glass (CPG) and Highly Cross-linked Polystyrene (HCP). In some embodiments, a solid support is a metal foam. In some embodiments, a solid support is a resin. In some embodiments, oligonucleotides are cleaved from a solid support.

[0195] In some embodiments, purity, particularly stereochemical purity, and particularly diastereomeric purity of many oligonucleotides and compositions thereof wherein all other chiral centers in the oligonucleotides but the chiral linkage phosphorus centers have been stereodefined (e.g., carbon chiral centers in the sugars, which are defined in, e.g., phosphoramidites for oligonucleotide synthesis), can be controlled by stereoselectivity (as appreciated by those skilled in this art, diastereoselectivity in many cases of oligonucleotide synthesis wherein the oligonucleotide comprise more than one chiral centers) at chiral linkage phosphorus in coupling steps when forming chiral internucleotidic linkages. In some embodiments, a coupling step has a stereoselectivity (diastereoselectivity when there are other chiral centers) of 60% at the linkage phosphorus. After such a coupling step, the new internucleotidic linkage formed may be referred to have a 60% stereochemical purity (for oligonucleotides, typically diastereomeric purity in view of the existence of other chiral centers). In some embodiments, each coupling step independently has a stereoselectivity of at least 60%, 70%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.5%. In some embodiments, a chirally controlled internucleotidic linkage is typically formed with a stereoselectivity of at least 85%, 87%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99.5% or virtually 100% (in some embodiments, at least 85%; in some embodiments, at least 87%; in some embodiments, at least 90%; in some embodiments, at least 95%; in some embodiments, at least 96%; in some embodiments, at least 97%; in some embodiments, at least 98%; in some embodiments, at least 99%). In some embodiments, a stereoselectivity is at least 85%. In some embodiments, a stereoselectivity is at least 87%. In some embodiments, a stereoselectivity is at least 90%. In some embodiments, each coupling step independently has a stereoselectivity of virtually 100%.

[0196] In some embodiments, stereopurity of a chiral center, e.g., a chiral linkage phosphorus, in a Page 69 of 20113318736vlAttorney Docket No.: 2010581-1667composition is at least 60%, 70%, 80%, 85%, 87%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.5%. In some embodiments, a stereopurity is at least 80%. In some embodiments, a stereopurity is at least 85%. In some embodiments, a stereopurity is at least 87%. In some embodiments, a stereopurity is at least 90%. In some embodiments, a stereopurity is virtually 100%. In some embodiments, each chirally controlled internucleotidic linkage independently has a stereochemical purity (typically diastereomeric purity for oligonucleotides with multiple chiral centers) of at least 85%, 87%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99.5% or virtually 100% (in some embodiments, at least 85%; in some embodiments, at least 87%; in some embodiments, at least 90%; in some embodiments, at least 95%; in some embodiments, at least 96%; in some embodiments, at least 97%; in some embodiments, at least 98%; in some embodiments, at least 99%) at its chiral linkage phosphorus. In some embodiments, a chirally controlled internucleotidic linkage has a stereochemical purity of at least 90%. In some embodiments, a majority of chirally controlled internucleotidic linkages independently have a stereochemical purity of at least 90%. In some embodiments, each chirally controlled internucleotidic linkage independently has a stereochemical purity of at least 90%. In some embodiments, each phosphorothioate internucleotidic linkage is independently chirally controlled. In some embodiments, at least 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, or all chirally controlled internucleotidic linkages are 5'p. In some embodiments, at least 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, or all chirally controlled phosphorothioate internucleotidic linkages are. Sp. In some embodiments, at least 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, or all phosphorothioate internucleotidic linkages are chirally controlled and are Sp.

[0197] Stereoselectivity and stereopurity may be assessed by various technologies. In some embodiments, stereoselectivity and / or stereopurity is virtually 100% in that when a composition is analyzed by an analytical method (e.g., NMR, HPLC, etc.), virtually all detectable stereoisomers has the intended stereochemistry.

[0198] In some embodiments, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 couplings of a monomer (as appreciated by those skilled in the art in many embodiments a phosphoramidite for oligonucleotide synthesis) independently have a stereoselectivity less than about 60%, 70%, 80%, 85%, or 90% [for oligonucleotide synthesis, typically diastereoselectivity with respect to formed linkage phosphorus chiral center(s)].

[0199] In some embodiments, in stereorandom (or racemic) preparations (or stereorandom / non-chirally controlled oligonucleotide compositions), at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 chiral internucleotidic linkages of the oligonucleotides independently have a stereochemical purity (typically diastereomeric purity for oligonucleotides comprising multiple chiral centers) less than about 60%, 65%, 70%, 75%, 80%, or 85% with respect to chiral linkage phosphorus of the internucleotidic linkage(s). In some embodiments, a stereochemistry purity (stereopurity) is less than about 60%. In some embodiments, a stereochemistry purity (stereopurity) is less than about 65%. In some embodiments, a stereochemistry purity (stereopurity) is less than about 70%. In some embodiments, a stereochemistry purity (stereopurity) is less than about 75%. In some embodiments, a stereochemistry purity Page 70 of 20113318736vlAttorney Docket No.: 2010581-1667(stereopurity) is less than about 80%.

[0200] In some embodiments, compounds of the present disclosure (e.g., oligonucleotides, chiral auxiliaries, etc.) comprise multiple chiral elements (e.g., multiple carbon and / or phosphorus (e.g., linkage phosphorus of chiral internucleotidic linkages) chiral centers). In some embodiments, at least 1, 2, 3, 4, 5, 6, 7, 8, 9 or more chiral elements of a provided compound (e.g., an oligonucleotide ) each independently have a diastereomeric purity as described herein. In some embodiments, a diastereomeric purity is at least 85%. In some embodiments, a diastereomeric purity is at least 86%. In some embodiments, a diastereomeric purity is at least 87%. In some embodiments, a diastereomeric purity is at least 88%. In some embodiments, a diastereomeric purity is at least 89%. In some embodiments, a diastereomeric purity is at least 90%. In some embodiments, a diastereomeric purity is at least 91%. In some embodiments, a diastereomeric purity is at least 92%. In some embodiments, a diastereomeric purity is at least 93%. In some embodiments, a diastereomeric purity is at least 94%. In some embodiments, a diastereomeric purity is at least 95%. In some embodiments, a diastereomeric purity is at least 96%. In some embodiments, a diastereomeric purity is at least 97%. In some embodiments, a diastereomeric purity is at least 98%. In some embodiments, a diastereomeric purity is at least 99%.

[0201] As understood by a person having ordinary skill in the art, in some embodiments, diastereoselectivity of a coupling or diastereomeric purity of a chiral linkage phosphorus center can be assessed through the diastereoselectivity of a dimer formation or diastereomeric purity of a dimer prepared under the same or comparable conditions, wherein the dimer has the same 5’- and 3 ’-nucleosides and internucleotidic linkage.

[0202] Various technologies can be utilized for identifying or confirming stereochemistry of chiral elements (e.g., configuration of chiral linkage phosphorus) and / or patterns of backbone chiral centers, and / or for assessing stereoselectivity (e.g., diastereoselectivity of couple steps in oligonucleotide synthesis) and / or stereochemical purity (e.g., diastereomeric purity of internucleotidic linkages, compounds (e.g., oligonucleotides), etc.). Example technologies include NMR [e.g., 1D (one-dimensional) and / or 2D (two-dimensional) ¹H-31P HETCOR (heteronuclear correlation spectroscopy)], HPLC, RP-HPLC, mass spectrometry, LC-MS, and cleavage of internucleotidic linkages by stereospecific nucleases, etc., which may be utilized individually or in combination. Example useful nucleases include benzonase, micrococcal nuclease, and svPDE (snake venom phosphodiesterase), which are specific for certain internucleotidic linkages with Rp linkage phosphorus (e.g., aRp phosphorothioate linkage); and nuclease Pl, mung bean nuclease, and nuclease SI, which are specific for internucleotidic linkages with Sp linkage phosphorus (e.g., a S'p phosphorothioate linkage). Without wishing to be bound by any particular theory, the present disclosure notes that, in at least some cases, cleavage of oligonucleotides by a particular nuclease may be impacted by structural elements, e.g., chemical modifications (e.g., 2’ -modifications of a sugars), base sequences, or stereochemical contexts. For example, it is observed that in some cases, benzonase and micrococcal nuclease, which are specific for internucleotidic linkages with Rp linkage phosphorus, were unable to cleave an isolated Rp phosphorothioate Page 71 of 20113318736vlAttorney Docket No.: 2010581-1667internucleotidic linkage flanked by Sp phosphorothioate internucleotidic linkages.

[0203] In some embodiments, oligonucleotides sharing a common base sequence, a common pattern of backbone linkages, and a common pattern of backbone chiral centers share a common pattern of backbone phosphorus modifications and a common pattern of base modifications. In some embodiments, oligonucleotide compositions sharing a common base sequence, a common pattern of backbone linkages, and a common pattern of backbone chiral centers share a common pattern of backbone phosphorus modifications and a common pattern of nucleoside modifications. In some embodiments, oligonucleotides share a common base sequence, a common pattern of backbone linkages, and a common pattern of backbone chiral centers have identical structures.

[0204] In some embodiments, a plurality of oligonucleotides or oligonucleotides of a particular oligonucleotide type in a provided oligonucleotide composition are oligonucleotides. In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein the oligonucleotides share:a common base sequence;a common pattern of backbone linkages; andthe same linkage phosphorus stereochemistry at one or more chiral internucleotidic linkages (chirally controlled internucleotidic linkages),wherein the composition is enriched, relative to a substantially racemic preparation of oligonucleotides sharing the common base sequence and pattern of backbone linkages, for oligonucleotides of the plurality.

[0205] In some embodiments, the present disclosure provides a chirally controlled oligonucleotide composition comprising a plurality of oligonucleotides, wherein the oligonucleotides share:a common base sequence;a common pattern of backbone linkages; anda common pattern of backbone chiral centers, which composition is a substantially pure preparation of a single oligonucleotide in that at least about 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 93%, 95%, 96%, 97%, 98%, or 99% of the oligonucleotides in the composition have the common base sequence, the common pattern of backbone linkages, and the common pattern of backbone chiral centers.

[0206] In some embodiments, an oligonucleotide composition type is further defined by: 4) additional chemical moiety, if any.

[0207] In some embodiments, the percentage is at least about 10%. In some embodiments, the percentage is at least about 20%. In some embodiments, the percentage is at least about 30%. In some embodiments, the percentage is at least about 40%. In some embodiments, the percentage is at least about 50%. In some embodiments, the percentage is at least about 60%. In some embodiments, the percentage is at least about 70%. In some embodiments, the percentage is at least about 75%. In some embodiments, the percentage is at least about 80%. In some embodiments, the percentage is at least about 85%. In some embodiments, the Page 72 of 20113318736vlAttorney Docket No.: 2010581-1667percentage is at least about 90%. In some embodiments, the percentage is at least about 91%, In some embodiments, the percentage is at least about 92%. In some embodiments, the percentage is at least about 93%. In some embodiments, the percentage is at least about 94%. In some embodiments, the percentage is at least about 95%. In some embodiments, the percentage is at least about 96%. In some embodiments, the percentage is at least about 97%. In some embodiments, the percentage is at least about 98%. In some embodiments, the percentage is at least about 99%. In some embodiments, the percentage is or is greater than (DS)nc, wherein DS and nc are each independently as described in the present disclosure.

[0208] In some embodiments, a plurality of oligonucleotides share the same constitution. In some embodiments, a plurality of oligonucleotides are identical (the same stereoisomer). In some embodiments, a chirally controlled oligonucleotide composition is a stereopure oligonucleotide composition wherein oligonucleotides of the plurality are identical (the same stereoisomer), and the composition does not contain any other stereoisomers. Those skilled in the art will appreciate that one or more other stereoisomers may exist as impurities as processes, selectivities, purifications, etc. may not achieve completeness.

[0209] In some embodiments, a provided composition is characterized in that when it is contacted with a target nucleic acid [e.g., a transcript (e.g., pre-mRNA, mature mRNA, other types of RNA, etc. that hybridizes with oligonucleotides of the composition)], levels of the target nucleic acid and / or a product encoded thereby is reduced compared to that observed under a reference condition. In some embodiments, levels of a nucleic acid and / or a product thereof, which nucleic acid is a product of an A to I edition of a target nucleic acid, is increased. In some embodiments, a reference condition is selected from the group consisting of absence of the composition, presence of a reference composition, and combinations thereof. In some embodiments, a reference condition is absence of the composition. In some embodiments, a reference condition is presence of a reference composition. In some embodiments, a reference composition is a composition whose oligonucleotides do not hybridize with the target nucleic acid. In some embodiments, a reference composition is a composition whose oligonucleotides do not comprise a sequence that is sufficiently complementary to the target nucleic acid. In some embodiments, a reference composition is a composition whose oligonucleotides share tire same base sequence but do not share the same nucleobase, sugar and / or internucleotidic linkage modifications. In some embodiments, a provided composition is a chirally controlled oligonucleotide composition and a reference composition is a non-chirally controlled oligonucleotide composition which is otherwise identical but is not chirally controlled (e.g., a racemic preparation of oligonucleotides of the same constitution as oligonucleotides of a plurality in the chirally controlled oligonucleotide composition).

[0210] As demonstrated herein, oligonucleotide structural elements (e.g., sugar modifications, backbone linkages, backbone chiral centers, backbone phosphorus modifications, patterns thereof, etc.) and combinations thereof can provide surprisingly improved properties and / or bioactivities.

[0211] In some embodiments, an oligonucleotide composition is a substantially pure preparation of a single oligonucleotide stereoisomer in that oligonucleotides in the composition that are of the same constitution but are not of the stereoisomer are impurities from the preparation process of said oligonucleotide stereoisomer,Page 73 of 20113318736vlAttorney Docket No.: 2010581-1667in some case, after certain purification procedures.

[0212] In some embodiments, the present disclosure provides oligonucleotides and oligonucleotide compositions that are chirally controlled, and in some embodiments, stereopure. For instance, in some embodiments, a provided composition contains non-random or controlled levels of one or more individual oligonucleotide types. In some embodiments, oligonucleotides of the same oligonucleotide type are identical. Nucleobases

[0213] Various nucleobases may be utilized in provided oligonucleotides in accordance with the present disclosure. In some embodiments, a nucleobase is a natural nucleobase, the most commonly occurring ones being A, T, C, G and U. In some embodiments, a nucleobase is a modified nucleobase in that it is not A, T, C, G or U. In some embodiments, a nucleobase is optionally substituted A, T, C, G or U, or a substituted tautomer of A T, C, G or U. In some embodiments, a nucleobase is optionally substituted A, T, C, G or U, e.g., 5mC, 5 -hydroxymethyl C, etc. In some embodiments, a nucleobase is alkyl-substituted A, T, C, G or U. In some embodiments, a nucleobase is A. In some embodiments, a nucleobase is T. In some embodiments, a nucleobase is C. In some embodiments, a nucleobase is G. In some embodiments, a nucleobase is U. In some embodiments, a nucleobase is 5mC. In some embodiments, a nucleobase is substituted A, T, C, G or U. In some embodiments, a nucleobase is a substituted tautomer of A, T, C, G or U. In some embodiments, substitution protects certain functional groups in nucleobases to minimize undesired reactions during oligonucleotide synthesis. Suitable technologies for nucleobase protection in oligonucleotide synthesis are widely known in the art and may be utilized in accordance with the present disclosure. In some embodiments, modified nucleobases improves properties and / or activities of oligonucleotides. For example, in many cases, 5mC may be utilized in place of C to modulate certain undesired biological effects, e.g., immune responses. In some embodiments, when determining sequence identity, a substituted nucleobase having the same hydrogen-bonding pattern is treated as the same as the unsubstituted nucleobase, e.g., 5mC may be treated the same as C [e.g., a oligonucleotide having 5mC in place of C (e.g., AT5mCG) is considered to have the same base sequence as a oligonucleotide having C at the corresponding location(s) (e.g., ATCG)]. In some embodiments, a nucleobase is or comprise an optionally substituted ring having at least one nitrogen atom. In some embodiments, a nucleobase comprise Ring BA as described herein, wherein at least one monocyclic ring of Ring BA comprise a nitrogen ring atom.

[0214] In some embodiments, an oligonucleotide comprises one or more A, T, C, G or U. In some embodiments, an oligonucleotide comprises one or more optionally substituted A, T, C, G or U. In some embodiments, an oligonucleotide comprises one or more 5-methylcytidine, 5 -hydroxymethylcytidine, 5-formylcytosine, or 5 -carboxylcytosine. In some embodiments, an oligonucleotide comprises one or more 5-methylcytidine. In some embodiments, each nucleobase in an oligonucleotide is selected from the group consisting of optionally substituted A, T, C, G and U, and optionally substituted tautomers of A, T, C, G and U. In some embodiments, each nucleobase in an oligonucleotide is optionally protected A, T, C, G and U. In some embodiments, each nucleobase in an oligonucleotide is optionally substituted A, T, C, G or U. In some Page 74 of 20113318736vlAttorney Docket No.: 2010581-1667embodiments, each nucleobase in an oligonucleotide is selected from the group consisting of A, T, C, G, U, and 5mC.

[0215] In some embodiments, the present disclosure provides oligonucleotides comprising one or more modified nucleobases as described herein. In some embodiments, the present disclosure provides compounds comprising modified nucleobases as described herein. In some embodiments, the present disclosure provides monomers (e.g., those useful for oligonucleotide synthesis) comprising modified nucleobases as described herein. In some embodiments, the present disclosure provides phosphoramidites comprising modified nucleobases as described herein. In some embodiments, phosphoramidites are CED phosphoramidites. In some embodiments, monomers comprise auxiliary moieties as described herein (e.g., with P forming bonds to O and N, to O and S, to S and S, etc.). In some embodiments, phosphoramidites comprise chiral auxiliary moieties as described herein (e.g., with P forming bonds to O and N). In some embodiments, RNScomprises a nucleobase as described herein. In some embodiments, RNScomprises a modified nucleobase as described herein. In some embodiments, nucleobases are protected for oligonucleotide synthesis.

[0216] As appreciated by those skilled in the art, various nucleobases are known in the art and can be utilized in accordance with the present disclosure, e.g., those described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, WO 2022 / 099159, and / or WO 2023 / 201095, the sugars, nucleobases, and internucleotidic linkages of each of which are independently incorporated herein by reference. In some embodiments, nucleobases are protected and useful for oligonucleotide synthesis.

[0217] In some embodiments, an oligonucleotide comprises a nucleobase or modified nucleobase as described in WO 2018 / 022473, WO 2018 / 098264, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, WO 2022 / 099159, and / or WO 2023 / 201095, the nucleobases including modified nucleobases of each of which are independently incorporated herein by reference.

[0218] In some embodiments, a provided oligonucleotide comprises a modified nucleobase described in, e.g., US 5552540, US 6222025, US 6528640, US 4845205, US 5681941, US 5750692, US 6015886, US 5614617, US 6147200, US 5457187, US 6639062, US 7427672, US 5459255, US 5484908, US 7045610, US 3687808, US 5502177, US 5525711 6235887, US 5175273, US 6617438, US 5594121, US 6380368, US 5367066, US 5587469, US 6166197, US 5432272, US 7495088, US 5134066, or US 5596091. In some embodiments, a nucleobase is described in WO 2020 / 154344, WO 2020 / 154343, WO 2020 / 154342, WO 2020 / 165077, WO 2020 / 201406, WO 2020 / 216637, WO 2020 / 252376, WO 2023 / 152371, WO 2024 / 110565, WO 2024 / 115635, WO 2024 / 121373, WO 2024 / 175550, or WO 2024 / 114908, and can be utilized in Page 75 of 20113318736vlAttorney Docket No.: 2010581-1667accordance with the present disclosure.

[0219] In some embodiments, a nucleobase is a protected base residue as used in oligonucleotide preparation. In some embodiments, a nucleobase is a base residue illustrated in US 2011 / 0294124, US 2015 / 0211006, US 2015 / 0197540, WO 2015 / 107425, WO 2017 / 192679, WO 2018 / 022473, WO 2018 / 098264, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, WO 2022 / 099159, and / or or WO 2023 / 201095, the base residues of each of which are independently incorporated herein by reference.Sugars

[0220] Various sugars, including modified sugars, can be utilized in accordance with the present disclosure. In some embodiments, the present disclosure provides sugar modifications and patterns thereof optionally in combination with other structural elements (e.g., internucleotidic linkage modifications and patterns thereof, pattern of backbone chiral centers thereof, etc.) that when incorporated into oligonucleotides can provide improved properties and / or activities.

[0221] The most common naturally occurring nucleosides comprise ribose sugars (e.g., in RNA) or deoxyribose sugars (e.g., in DNA) linked to the nucleobases adenosine (A), cytosine (C), guanine (G), thymine (T) or uracil (U). In some embodiments, a sugar, e.g., various sugars in many oligonucleotides in Table 1 (unless otherwise notes), is a natural DNA sugar (in DNA nucleic acids or oligonucleotides, having thestructure of, wherein a nucleobase is attached to the 1’ position, and the 3’ and 5’ positions are connected to internucleotidic linkages (as appreciated by those skilled in the art, if at the 5 ’-end of oligonucleotide, the 5’ position may be connected to a 5’-end group (e.g., -OH), and if at the 3’-end of an oligonucleotide, the 3’ position may be connected to a 3’-end group (e.g., -OH)). In some embodiments, asugar is a natural RNA sugar (in RNA nucleic acids or oligonucleotides, having the structure of OH, wherein a nucleobase is attached to the 1’ position, and the 3’ and 5’ positions are connected to internucleotidic linkages (as appreciated by those skilled in the art, if at the 5 ’-end of an oligonucleotide, the 5’ position may be connected to a 5’-end group (e.g., -OH), and if at the 3’-end of an oligonucleotide, the 3’ position may be connected to a 3 ’-end group (e.g., -OH)). In some embodiments, a sugar is a modified sugar in that it is not a natural DNA sugar or a natural RNA sugar. Among other things, modified sugars may provide improved stability. In some embodiments, modified sugars can be utilized to alter and / or optimize one or more hybridization characteristics. In some embodiments, modified sugars can be utilized to alter and / or optimize target nucleic acid recognition. In some embodiments, modified sugars can be utilized to optimize Tm. In Page 76 of 20113318736vlAttorney Docket No.: 2010581-1667some embodiments, modified sugars can be utilized to improve oligonucleotide activities. Those skilled in the art appreciate that, unless specified otherwise, carbon atoms of sugars with indicated connections (e.g., the 5’-and / or 3’-carbons) typically bond to -OH (e.g., when at the ends of oligonucleotides) and / or oxygen atoms which bond to linkage phosphorus atoms in internucleotidic linkages (see, e.g., various oligonucleotides in Table 1). Those skilled in the art appreciate that, unless specified otherwise, oxygen atoms bonded to carbon atoms of sugars with indicated connections herein may be considered part of a sugar if so desired, and may also be considered part of an internucleotidic linkage if so desired.

[0222] Among other things, the present disclosure demonstrates that various non-natural RNA sugars, such as natural DNA sugar, various modified sugars, etc., may be utilized in accordance with the present disclosure. For example, one or more natural DNA sugars can be tolerated at various positions. In some embodiments, a modified sugar is a bicyclic sugar (e.g., a LNA sugar, a cEt sugar, etc.). In some embodiments, a bicyclic sugar may be utilized at one or more or all positions where a 2 ’-OR sugar is utilized, wherein R is optionally substituted C1-6alkyl. In some embodiments, 2’-OR is 2’-OMe. In some embodiments, 2’-OR is 2’-M0E. In some embodiments, a majority is at least 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% (e.g., 55%-100%, 60%-100%, 70-100%, 75%-100%, 80%-100%, 90%-100%, 95%-100%, 60%-95%, 70%-95%, 75-95%, 80-95%, 85-95%, 90-95%, 51%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%, etc.

[0223] Sugars can be bonded to internucleotidic linkages at various positions. As non-limiting examples, internucleotidic linkages can be bonded to the 2’, 3’, 4’ or 5’ positions of sugars. In some embodiments, as most commonly in natural nucleic acids, an internucleotidic linkage connects with one sugar at the 5’ position and another sugar at the 3’ position unless otherwise indicated.

[0224] In some embodiments, a sugar is an optionally substituted natural DNA or RNA sugar. In someembodiments, a sugar is optionally substitutedIn some embodiments, the 2’ position isoptionally substituted. In some embodiments, a sugar isIn some embodiments, a sugar has. wherein each of Rls, R2s, R3s, R4s, and R5sis independently -H, a suitable substituent or suitable sugar modification (e.g., those described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194,Page 77 of 20113318736vlAttorney Docket No.: 2010581-1667WO 2019 / 032607, WO 2019 / 032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, WO 2022 / 099159, and / or WO 2023 / 201095, the substituents, sugar modifications, descriptions of Rls, R2s, R3s, R4s, and R5s, and modified sugars of each of which are independently incorporated herein by reference). In some embodiments, each of Rls, R2s, R3s, R4s, and R5sis independently Rs, wherein each Rsis independently -F, -Cl, -Br, -I, -CN, -N3, -NO, -NO2, -Ls— R’, -LS-OR’, -LS-SR’, -LS-N(R’)2, -O-LS-OR’, -O-LS-SR’, or -O-LS-N(R’)2, wherein each R’ is independently as described herein, and each Lsis independently a covalent bond or optionally substituted bivalent C1-6 aliphatic or heteroaliphatic having 1-4 heteroatoms; or two Rsare taken together to form a bridge -Ls- In some embodiments, R’ is optional ly substituted C1-10 aliphatic. In some embodiments,a sugar has the structureof In some embodiments, a sugar has the structureof. In some embodiments, a sugar has the structureof In some embodiments, a sugar has theIn some embodiments, In someembodiments, a sugar has the structureof1R2s. In some embodiments, a sugar has the structure ofIn some embodiments, a sugar has the structureof ■. In some embodiments, asugar has the structureof In some embodiments, R5sis optionally substituted C1-6aliphatic. In some embodiments, R3sis optionally substituted C1-6alkyl. In some embodiments, R5sis optionally substituted methyl. In some embodiments, R5sis methyl. In some embodiments, a sugar has the structure ofPage 78 of 20113318736vlAttorney Docket No.: 2010581-1667. In some embodiments, a sugar has the structureof. In some embodiments, asugar has the structure of. Various such sugars are utilized in Table 1. In some embodiments,a sugar has the structureof In some embodiments, a 2’ -modified sugar has the structure of, wherein R2sis a 2’ -modification. In some embodiments, a sugar has the structure of, wherein R2sis -H, halogen, or -OR, wherein R is optionally substituted C1-6aliphatic. In some embodiments, R2Sis -H. In some embodiments, R2sis -F. In some embodiments, R2sis -OMe. In some embodiments, a modified nucleoside is mA, mT, mC, m5mC, mG, mU, etc., in which R2sis -OMe. In some embodiments, R2sis -OCFFCFEOMe. In some embodiments, a modified nucleoside is Aeo, Teo, Ceo, m5Ceo, Geo, Ueo, etc., in which R2sis -OCITCtFOMe. In some embodiments, R2sis -OCH2CH2OH. In some embodiments, anoligonucleotide comprises a 2’ -F modified sugar having the structure of1F (e.g., as in fA, fT, fC, f5mC, fG, fU, etc.). In some embodiments, an oligonucleotide comprises a 2’-OMe modified sugar having thestructure of ' OMe (e.g., as indicated by m). In some embodiments, an oligonucleotide comprises a2 ’-MOE modified sugar having the structure of1OCH2CH2OCH3 (e.g., as indicated by [moe]).

[0225] In some embodiments, a sugar has the structure of wherein R2sand R4sare taken together to form -Ls-, wherein Lsis a covalent bond or optionally substituted bivalent Ci-6 aliphatic or Page 79 of 20113318736vlAttorney Docket No.: 2010581-1667heteroaliphatic having 1-4 heteroatoms. In some embodiments, each heteroatom is independently selected from nitrogen, oxygen or sulfur). In some embodiments, Lsis optionally substituted C2-O-CH2-C4. In some embodiments, Lsis C2-O-CH2-C4. In some embodiments, Lsis C2-O-(R)-CH(CH2CH3)-C4. In some embodiments, Lsis C2-O-(S)-CH(CH2CH3)-C4.

[0226] In some embodiments, a sugar has the structure of wherein each variable isindependently as described herein. In some embodiments, a sugar has the structure of, wherein each variable is independently as described herein. In some embodiments, R3sis -H. In some embodiments,a sugar has the structure of, wherein each variable is independently as described herein. In some embodiments, R3sis -OH. In some embodiments, R3sis -H. In some embodiments, a sugar isOH1. in some embodiments, a sugar is

[0227] In some embodiments, a sugar is optionally substituted, wherein Xsis -S-, -Se-, or optionally substituted -CHj-. In some embodiments, the 2’ position is optionally substituted. In someembodiments, a sugar isIn some embodiments, a sugar has the structure of, wherein each of Rls, R2s, R3s, R4s, and R5sis independently -H, a suitable substituent or suitable sugar modification (e.g., those described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO Page 80 of 20113318736vlAttorney Docket No.: 2010581-16672019 / 032607, WO 2019 / 032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, WO 2022 / 099159, and / or WO 2023 / 201095, the substituents, descriptions of R1s, R2s, R3s, R4s, and R5s, and modified sugars of each of which are independently incorporated herein by reference). In some embodiments, each of R1s, R2s, R3s, R4s, and R5sis independently Rs, wherein each Rsis independently -F, -Cl, -Br, -I, -CN, -N3, -NO, -NO2, -Ls-R’, -LS-OR’, -LS-SR’, -LS-N(R’)2, - O- Ls- OR’, -O-LS-SR’, or -O-LS-N(R’)2, wherein each R’ is independently as described herein, and each Lsis independently a covalent bond or optionally substituted bivalent C1-6 aliphatic or heteroaliphatic having 1-4 heteroatoms; or two Rsare taken together to form a bridge -Ls-. In some embodiments, R’ is optionally substituted C1-10 aliphatic. In some embodiments, a sugar has the structure of5' XsIR4SIn some embodiments, a sugar has the structureof1R2SIn some embodiments, asugar has the structureof In some embodiments, a sugar has the structureofIn some embodiments, a sugar has the structureof In some embodiments, a sugar has the A 51]"R5s_ JW 'VXsI4'^JWV ' 2 structureof R. In some embodiments, sugar has the structureof '. In someembodiments, a sugar has the structureof. In some embodiments, a sugar has the structure ofIn some embodiments, R5sis optionally substituted C1-6aliphatic. In some embodiments, R3sis optionally substituted C1-6alkyl. In some embodiments, R5sis optionally substituted methyl. In someembodiments, R is methyl. In some embodiments, a sugar has the structureof i. In some Page 81 of 20113318736vlAttorney Docket No.: 2010581-1667embodiments, a sugar has the structureof '. In some embodiments, a sugar has the structure of. Various such sugars are utilized in Table 1. In some embodiments, a sugar has the structureIn some embodiments, a 2 ’-modified sugar has the structure ofis a 2 ’-modification. In some embodiments, a sugar has the structure of, wherein R2sis -H, halogen, or -OR, wherein R is optionally substituted C1-6aliphatic. In some embodiments, R2sis -H. In some embodiments, R2sis -F. In some embodiments, R2sis -OMe. In some embodiments, R2sis -OCH2CH2OMe. In some embodiments, R2sis -OCH2CH2OH. In some embodiments, a modified sugar has the structure ofIn some embodiments, a modified sugar has the structureof ' OMe. In someembodiments, a modified sugar having the structureof OCH2CH2OCH3 jn someembodiments, amodified sugar having the structure of. In some embodiments, Xsis -S-. In some embodiments, Xsis optionally substituted -CH2-. In some embodiments, Xsis -CH2-. In some embodiments, a modifiedsugar having the structureof 1. In some embodiments, a modified sugar having the structure ofPage 82 of 20113318736vlAttorney Docket No.: 2010581-1667

[0228] In some embodiments, a sugar has the structure of, wherein each R2sis independently -H, -F, -OH or -ORak, wherein Rakis optionally substituted C1-6aliphatic, and each of the other variables is independently as described herein. In some embodiments, each of R1s, R3s, R4s, and R5sis independently -H. In some embodiments, each of R1s, R3sand R4s, and one of R5s, are independently -H, and the other R’sis independently Ci-6 aliphatic. In some embodiments, an occurrence of R5sis Ci-6 aliphatic, e.g., methyl. In some embodiments, R2sis -H. In some embodiments, R2sis -F. In some embodiments, R2sis -ORak. In some embodiments, R2sis -OMe. In some embodiments, R2sis -OCH2CH2CH3. In some embodiments, at least one occurrence of R2sis -H. In some embodiments, at least one occurrence of R2sis not -H. In some embodiments, Xsis -O-. In some embodiments, Xsis -S-. In some embodiments, Xsis optionally substituted -CH2-. In some embodiments, Xsis -CH2-.R4S 1 [

[0229] In some embodiments, a sugar has the structure of1Rs, wherein R2sand R4sare taken together to form -Ls-, wherein Lsis a covalent bond or optionally substituted bivalent Ci-6 aliphatic or heteroaliphatic having 1-4 heteroatoms. In some embodiments, each heteroatom is independently selected from nitrogen, oxygen or sulfur). In some embodiments, Lsis optionally substituted C2-O-CH2-C4. In some embodiments, Lsis C2-O-CH2-C4. In some embodiments, Lsis C2-O-(R)-CH(CH2CH3)-C4. In some embodiments, Lsis C2-O-()-CH(CH2CH3)-C4. In some embodiments, Xsis -S-. In some embodiments, Xsis optionally substituted -CH2-. In some embodiments, Xsis -CH2-. In some embodiments, Xsis -Se-

[0230] In some embodiments, a sugar has the structure of wherein each variable isPage 83 of 20113318736vlAttorney Docket No.: 2010581-1667independently as described herein. In some embodiments, a sugar has the structureof each variable is independently as described herein. In some embodiments, R5sis -H. In some embodiments,a sugar has the structureof, wherein each variable is independently as described herein. In some embodiments, R3sis -OH. In some embodiments, R3sis -H. In some embodiments, Xsis -S-. In some embodiments, Xsis optionally substituted -CH2-. In some embodiments, Xsis -CH2-.

[0231] In some embodiments, a nucleoside comprising a modified sugar has the structure of 'Z ^BA®<~izvor a salt form thereof, wherein B Asis -H or an optionally substituted or protected nucleobase (e.g., BA), and R2sis as described herein. In some embodiments, R2sis -OH, halogen, or optionally substituted Ci-Ce alkoxy. In some embodiments, BASis -H. In some embodiments, BASis an optionally substituted or protected nucleobase. In some embodiments, BASis BA. In some embodiments, R2sis -F. In some1 [ ' RASembodiments, a nucleoside comprising a modified sugar has the structure2SD MofRor a salt form thereof, wherein each variable is independently as described herein. In some embodiments, R2sis -H, -OH, halogen, or optionally substituted Ci-Ce alkoxy. In some embodiments, R2sis -H. In some embodiments, R2sis -F. In some embodiments, a nucleoside comprising a modified sugar has die structure of 1 wherein each variable is as described herein. In some embodiments, a nucleoside comprising a modified sugar " A 1 - BAShas the structure ofr2sor a salt form thereof, wherein each variable is independently as described herein. In some embodiments, R2sis -H, -OH, halogen, or optionally substituted Ci-Ce alkoxy. In some embodiments, R2sis -H. In some embodiments, R2sis -F. In some embodiments, a nucleosidecomprising a modified sugar has the structureof or a salt form thereof, wherein R2sis Rs,Page 84 of 20113318736vlAttorney Docket No.: 2010581-1667and each of Rs, R2sand BASis independently as described herein. In some embodiments, each of R2sand R2s'is independently -H, -OH, halogen, or optionally substituted C1-C6alkoxy. In some embodiments, R2sis -H. In some embodiments, R2sis -OH. In some embodiments, R2sis halogen. In some embodiments, R2sis -F. In some embodiments, R2sis optionally substituted Ci-Ce alkoxy. In some embodiments, R2sis -H. In some embodiments, R2sis -OH. In some embodiments, R2sis halogen. In some embodiments, R2sis -F. In some embodiments, R2sis optionally substituted Ci-Ce alkoxy. In some embodiments, BASis -H. In some embodiments, BASis an optionally substituted or protected nucleobase. In some embodiments, BASis BA. In some embodiments, nucleobases such as BA are optionally substituted or protected for oligonucleotide synthesis. Certain such nucleosides including sugars and nucleobases and uses thereof are described in WO 2020 / 154342. In some embodiments, an oligonucleotide comprises arabinoside, 2 ’-deoxy-2’ -fluoroarabinoside, 2’-OR arabinoside, adeoxycytidine, DNA-abasic, RNA-abasic, or 2’-OR abasic, wherein R is not hydrogen (e.g., optionally substituted C1-6aliphatic). In some embodiments, 2’-OR is 2’-OMe. In some embodiments, 2’-OR is 2’-M0E. In some embodiments, an oligonucleotide comprises 2’-O-methyl-arabinocytidine (amC). In some embodiments, oligonucleotides comprise such nucleosides. In some embodiments, monomers comprise such nucleosides. In some embodiments, phosphoramidites comprise such nucleosides (in some embodiments, one connecting site (e.g., a -CH2- connecting site) is bonded to an optionally substituted -OH, e.g., (-ODMTr), and one connecting site (e.g., a ring connecting site) is bonded to O which is also bonded to P of a phosphoramidite). In some embodiments, one or more or each of a 5’ immediate nucleoside (e.g., Ni), an opposite nucleoside (No) and a 3’ immediate nucleoside (e.g., N-i) is independently such a nucleoside. In some embodiments, 5’-NiNoN-i-3’ is amCCA. In some embodiments, a5sugar has the structureof, wherein each variable is as described herein and Cl’ is bonded to a nucleobase. In some embodiments, a sugar is an arabinose. In some embodiments, a sugar has the structure. / OH 1o-|l, wherein Cl’ is bonded to a nucleobase.

[0232] In some embodiments, a sugar is optionally substituted, wherein a nucleobase isbonded at position 1’. In some embodiments, a sugaris1, wherein a nucleobase is bonded at position 1 ’.Page 85 of 20113318736vlAttorney Docket No.: 2010581-1667

[0233] In some embodiments, a sugar is optionally substitutedbonded to a nucleobase, Xsis -O-, -S-, -Se- or optionally substituted -CH2-. In some embodiments, a sugar’n ’n is. In some embodiments, a sugar is optionally substituted' ‘, wherein position a is bonded to a nucleobase, Xsis -O-, -S-, -Se- or optionally substituted -CH2-. In someJ— J>embodiments, a sugar isn. In some embodiments, Xsis -O-. In some embodiments, Xsis -S-. In some embodiments, Xsis -Se-. In some embodiments, Xsis optionally substituted -CH2-. In some embodiments, Xsis -CH2-. In some embodiments, n is 0. In some embodiments, n is 1. In some embodiments, n is 2. In some embodiments, n is 3.

[0234] In some embodiments, a modified sugar comprises an optionally substituted 6-membered ring having 0-1 oxygen atom. In some embodiments, a modified sugar comprises an optionally substituted 6-membered ring having an oxygen atom. For example, in some embodiments, a modified sugar has the structureof optionally substituted ', wherein position a is bonded to a nucleobase. In someembodiments, a modified sugar has the structureof ', wherein position a is bonded to anucleobase. in some embodiments, a modified sugar has the structure of optionally substituted ', wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure ofi, wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the A I0_ xyv iwstructure of, wherein position a is bonded to a nucleobase. In some embodiments, a modifiedsugar has the structure of optionally substituted i, wherein position a is bonded to a nucleobase.Page 86 of 20113318736vlAttorney Docket No.: 2010581-1667In some embodiments, a modified sugar has the structure ofwherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure of optionally substituted, wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar haswherein position a is bonded to a nucleobase. In some embodiments, amodified sugar has the structure of optionally substituted- / vi~, wherein position a is bonded to a Anucleobase. In some embodiments, a modified sugar has the structure of, wherein position a is bonded to a nucleobase.

[0235] In some embodiments, a nucleoside comprising a modified sugar has the structure of 'A0BASR or a salt form thereof, wherein each of R6sand R7sis independently Rs, BASis -H or an optionally substituted or protected nucleobase (e.g., BA), and Rsis independendy as described herein. In some embodiments, R6sis -H, -OH or halogen, and R7sis -H, -OH, halogen or optionally substituted Ci-Ce alkoxy. In some embodiments, BASis -H. In some embodiments, BASis an optionally substituted or protected nucleobase. In some embodiments, BASis BA. In some embodiments, a nucleoside comprising a modifiedsugar has the structureof or a salt form thereof, wherein each of R8sand R9sis independently Rs, and each of Rsand BASis independently as described herein. In some embodiments, R8sis -H or halogen, and R9sis -H, -OH, halogen, or optionally substituted Ci-Ce alkoxy. In some embodiments,a nucleoside comprising a modified sugar has the structureof or a salt form thereof,Page 87 of 20113318736vlAttorney Docket No.: 2010581-1667wherein each of R10sand R11sis independently Rs, and each of Rsand B Asis independently as described herein. In some embodiments, R10sis -H or halogen, and R11sis -H, -OH, halogen, or optionally substituted C1-C6alkoxy. In some embodiments, a nucleoside comprising a modified sugar has the structure ofBASor a salt form thereof, wherein BASis as described herein. In some embodiments, aBASNnucleoside comprising a modified sugar has the structure of or a salt form thereof, wherein B Asis as described herein. Those skilled in the art appreciate that in some embodiments, the nitrogen may be directly bonded to linkage phosphorus. In some embodiments, a halogen is -F. In some embodiments, BASis -H. In some embodiments, B Asis an optionally substituted or protected nucleobase. In some embodiments, BASis BA. In some embodiments, nucleobases such as BA are optionally substituted or protected for oligonucleotide synthesis. In some embodiments, an oligonucleotide comprises alpha-homo-DNA, beta- homo-DNA moieties. In some embodiments, an oligonucleotide comprises an alpha- or beta-homo-DNA sugar. In some embodiments, an oligonucleotide comprises an alpha-homo-DNA sugar. In some embodiments, an oligonucleotide comprises a beta-homo-DNA sugar. Certain such nucleosides including sugars and nucleobases and uses thereof are described in WO 2020 / 154343. In some embodiments, oligonucleotides comprise such nucleosides. In some embodiments, monomers comprise such nucleosides. In some embodiments, phosphoramidites comprise such nucleosides (in some embodiments, one connecting site (e.g., a -CH2- connecting site) is bonded to an optionally substituted -OH, e.g., -ODMTr, and one connecting site (e.g., a ring connecting site) is bonded to P of a phosphoramidite (e.g., when the connecting ring atom is N) or to O which is also bonded to P of a phosphoramidite(e.g., when the connecting ring atom is C)). In some embodiments, one or more or each of a 5’ immediate nucleoside (e.g., Ni), an opposite nucleoside (No) and a 3’ immediate nucleoside (e.g., N-i) is independently such a nucleoside.•z, / \ a

[0236] In some embodiments, a modified sugar has the structure of, wherein position ais bonded to a nucleobase. In some embodiments, a modified sugar has the structureof wherein position a is bonded to a nucleobase. In some embodiments, a modified sugar has the structure ofOR", wherein position a is bonded to a nucleobase, position b is bonded to an internucleoside Page 88 of 20113318736vlAttorney Docket No.: 2010581-1667linkage and R” is -H or optionally substituted C1-6aliphatic. In some embodiments, a modified sugar has theR" O" \ _ / structure of ' OR", wherein position a is bonded to a nucleobase, position b is bonded to an internucleoside linkage and R” is -H or Ci-6 aliphatic. In some embodiments, a modified sugar has theR" O' \ )) — (bstructure of R" O ', wherein position a is bonded to a nucleobase, position b is bonded to an internucleoside linkage and R” is -H or Ci-6 aliphatic. In some embodiments, R” is methyl.JX / X IJX / B | AS

[0237] In some embodiments, a nucleoside comprising a modified sugar has the structure ofor a salt form thereof, wherein each variable is as described herein. In some embodiments, a nucleoside ^LvBAScomprising a modified sugar has the structure of ‘~TZor a salt form thereof, wherein each variable is as described herein. In some embodiments, a nucleoside comprising a modified sugar has the structure ofor a salt form thereof, wherein each variable is as described herein. In some embodiments, a i uBA®?12 Y onucleoside comprising a modified sugar has the structure of Rsor a salt form thereof, wherein R12sis Rs, and each of Rsand BASis independently as described herein. In some embodiments, R12sis -H, -OH, halogen, optionally substituted C1-6alkyl, optionally substituted C1-6heteroalkyl, or optionally substituted Ci-e alkoxy. In some embodiments, a halogen is -F. In some embodiments, a nucleosidecomprising a modified sugar has the structureof or a salt form thereof, wherein each variable is as described herein. In some embodiments, a nucleotide comprising a modified sugar has thestructureof or a salt form thereof, wherein R13sis Rs, and each of Rsand BASis Page 89 of 20113318736vlAttorney Docket No.: 2010581-1667independently as described herein. In some embodiments, R13sis -H or optionally substituted Ci-Ce alkyl. Insome embodiments, a nucleoside comprising a modified sugar has the structureof or a salt form thereof, wherein each variable is as described herein. In some embodiments, a nucleotidecomprising a modified sugar has the structureof or a salt form thereof, wherein each variable is as described herein. In some embodiments, a linkage is an amide linkage. In some embodiments, BASis -H. In some embodiments, BASis an optionally substituted or protected nucleobase. In some embodiments, BASis BA. In some embodiments, nucleobases such as BA are optionally substituted or protected for oligonucleotide synthesis. Certain such nucleosides and nucleotides including sugars and nucleobases and uses thereof are described in WO 2020 / 154344. In some embodiments, oligonucleotides comprise such nucleosides. In some embodiments, oligonucleotides comprise such nucleosides (in some embodiments, one connecting site (e.g., a -CH2- connecting site) is bonded to an optionally substituted -OH, e.g., (-ODMTr), and one connecting site (e.g., a ring connecting site) is bonded to O which is also bonded to P of a phosphoramidite. In some embodiments, one or more or each of a 5’ immediate nucleoside (e.g., Ni), an opposite nucleoside (No) and a 3’ immediate nucleoside (e.g., N-i) is independently such a nucleoside.

[0238] In some embodiments, a sugar is an acyclic sugar, e.g. a UNA sugar. In some embodiments, asugar is optionally substituted. In some embodiments, the 2’ position is optionally substituted.In some embodiments, a sugar is. In some embodiments, R2sis -OH. In some embodiments, a sugar is wherein indicates thePage 90 of 20113318736vlAttorney Docket No.: 2010581-1667carbon atom bonded to a nucleobase. In some embodiments, a sugar is, wherein "*" indicates the carbon atom bonded to a nucleobase. In some embodiments, the carbon atom bonded to a nitrogen atom of a nucleobase and is of R configuration (e.g., sm18). In some embodiments, an oligonucleotide comprises a sugar described herein.

[0239] In some embodiments, a sugar is optionally substituted, wherein position a is bonded to a nucleobase, Xsis -O-, -S-, -Se- or optionally substituted -CH2. In some embodiments, a sugaris. In some embodiments, Xsis -O-. In some embodiments, Xsis -S-. In some embodiments, Xsis -Se- In some embodiments, Xsis optionally substituted -CH2-. In some embodiments, Xsis -CH2-. In some embodiments, n is 0. In some embodiments, n is 1. In some embodiments, n is 2. In some embodiments, n is 3.

[0240] In some embodiments, a sugar is an optionally substituted 6-membered ring. In some embodiments, a sugar comprises no substituent at a position corresponding to 2 ’-OH of a natural RNA sugar. In some embodiments, a sugar comprises no 2’-substituent. In some embodiments, a sugar is a 5’-modified sugar. In some embodiments, a sugar is a 5 ’-Me modified sugar. In some embodiments, a sugar is a non-cyclic sugar. In some embodiments, a sugar is smOl. In some embodiments, a sugar is sml5. In some embodiments, a sugar is a substituted natural DNA sugar one of whose 2’-H is substituted with -OH or -F and the other 2’-H is not substituted. In some embodiments, a sugar is a natural DNA sugar.

[0241] In some embodiments, a sugar is optionally substituted, wherein position si is bonded to a nucleobase, Xsis -O-, -S-, or optionally substituted -CH2-, and Xs2is an optionally substitutedbivalent C1-6 aliphatic chain. In some embodiments, a sugar is. In some embodiments, Xsis -O-. In some embodiments, Xsis -S-. In some embodiments, Xsis -CH2-. In some embodiments, Xs2is an optionally substituted bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted saturated bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted unsaturated bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C2 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C3 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C4 aliphatic chain. In some embodiments, Xs2is an optionally substituted Page 91 of 20113318736vlAttorney Docket No.: 2010581-1667bivalent C5 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent Ce aliphatic chain. In some embodiments, Xs2is substituted. In some embodiments, Xs2is unsubstituted. In some embodiments, Xs2is optionally substituted -CH2-. In some embodiments, Xs2is -CH2-CH2-. In some embodiments, Xs2is -CH=CH- In some embodiments, Xs2is -CH2-CH2-CH2-. In some embodiments, Xs2is -CH=CH-CH2-. In some embodiments, -CH2- is bonded to the carbon at position si. In some embodiments, a sugar is a sugar of No. In some embodiments, a sugar is a sugar of N-i. In some embodiments, a sugar is a sugar of N+i.j,Xs2

[0242] In some embodiments, a sugar is optionally substituted —I—, wherein position si is bonded to a nucleobase, Xsis -O-, -S-, or optionally substituted -CH2-, and Xs2is an optionally substitutedTxsJbivalent C1-6 aliphatic chain. In some embodiments, a sugaris. In some embodiments, Xsis -O-. In some embodiments, Xsis -S-. In some embodiments, Xsis -CH2-. In some embodiments, Xs2is an optionally substituted bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted saturated bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted unsaturated bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C2 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C3 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C4 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C5 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent Ce aliphatic chain. In some embodiments, Xs2is substituted. In some embodiments, Xs2is unsubstituted. In some embodiments, Xs2is optionally substituted -CH2-. In some embodiments, Xs2is -CH2-CH2-. In some embodiments, Xs2is -CH=CH- In some embodiments, Xs2is -CH2-CH2-CH2-. In some embodiments, Xs2is -CH=CH-CH2-. In some embodiments, -CH2- is bonded to the carbon at position si. In some embodiments, a sugar is a sugar of No. In some embodiments, a sugar is a sugar of N-i. In some embodiments, a sugar is a sugar of N+i.

[0243] In some embodiments, a sugar is optionally substituted, wherein position si is bonded to a nucleobase, Xsis -O-, -S-, or optionally substituted -CH2-, and Xs2is an optionally substitutedbivalent C1-6 aliphatic chain. In some embodiments, a sugar is• -. In some embodiments, Xsis -O-. In some embodiments, Xsis -S-. In some embodiments, Xsis -CH2-. In some embodiments, Xs2is an optionally substituted bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted saturated bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted unsaturated Page 92 of 20113318736vlAttorney Docket No.: 2010581-1667bivalent C2-6 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C2 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C3 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C4 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent C5 aliphatic chain. In some embodiments, Xs2is an optionally substituted bivalent Ce aliphatic chain. In some embodiments, Xs2is substituted. In some embodiments, Xs2is unsubstituted. In some embodiments, Xs2i...

Claims

Attorney Docket No.: 2010581-1667CLAIMS1. An oligonucleotide, wherein the oligonucleotide is:[moe]([m5C])[Ssp].[moe](T)[n001R].[moe]([m5C])p.[moe](T)[n001R].[moe](G)[Ssp].d(G)[Ssp].d( G)[Rsp].d(T)[Ssp].d(T)[Rsp].d(G)[Ssp].d(C)[Ssp].d(T)[Ssp].d(G)[Rsp].d(G)[Ssp].d(G)[Ssp].m(U)[Ssp].m(C )[n001R].m(A)[Ssp].m(C)[Ssp].m(U) or a salt thereof, wherein:[moe] represents a 2 ’-MOE ^’-OCELCHjOCth) modification to a nucleoside;[m5C] represents 5-methyl C;[Ssp] represents a Sp phosphorothioate linkage;[nOOIR] represents Rp N-( 1,3-dimethylimidazolidin-2-ylidene) phosphoramidate linkage;p represents a phosphate linkage;d represents 2’-deoxy;[Rsp] represents a Rp phosphorothioate linkage; andm represents a 2’-0Me modification to a nucleoside.

2. The oligonucleotide of any one of the preceding claims, wherein the oligonucleotide is a salt.

3. The oligonucleotide of any one of the preceding claims, wherein the oligonucleotide is a pharmaceutically acceptable salt.

4. The oligonucleotide of any one of the preceding claims, wherein the oligonucleotide is a sodium salt.

5. The oligonucleotide of any one of claims 1-3, wherein the oligonucleotide is an ammonium salt.

6. The oligonucleotide of any one of the preceding claims, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%.

7. The oligonucleotide of any one of the preceding claims, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 90%.

8. The oligonucleotide of any one of the preceding claims, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 95%.

9. The oligonucleotide of any one of the preceding claims, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 98%.

10. The oligonucleotide of any one of the preceding claims, wherein the diastereomeric purity of the oligonucleotide is about or at least about (DS)nc, wherein DS is about 85%-100% (e.g., about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%), and nc is the number of cliiral linkage phosphorus in the oligonucleotide.

11. The oligonucleotide of claim 10, wherein DS is about or at least about 90%.

12. The oligonucleotide of claim 10, wherein DS is about or at least about 95%.

13. The oligonucleotide of claim 10, wherein DS is about or at least about 98%.

14. The oligonucleotide of claim 10, wherein DS is about or at least about 99%.Page 196 of 20113318736vlAttorney Docket No.: 2010581-166715. The oligonucleotide of any one of the preceding claims, wherein the purity of the oligonucleotide is about 20%-100%, or is about or at least about 20%-95%, about 30%-90%, about 40%-85%, about 40%-80%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 75%, about 80%, about 85%, or about 90%.

16. An oligonucleotide composition comprising a plurality of oligonucleotides, wherein each oligonucleotide of the plurality is independently an oligonucleotide of any one of the preceding claims.

17. The composition of claim 16, wherein one or more oligonucleotides of the plurality are independently a salt.

18. The composition of claim 16, wherein one or more oligonucleotides of the plurality are independently a pharmaceutically acceptable salt.

19. The composition of any one of claims 16-18, wherein the composition is enriched for oligonucleotides of the plurality compared to a stereorandom preparation of the oligonucleotides wherein no internucleotidic linkages are chirally controlled.

20. The composition of any one of claims 16-19, wherein a non-random level of all oligonucleotides in the composition that share the common base sequence and the same base and sugar modifications are oligonucleotides of the plurality.

21. The composition of any one of claims 16-20, wherein each oligonucleotide of the plurality is independently a pharmaceutically acceptable salt.

22. The composition of any one of claims 16-21, wherein oligonucleotides of the plurality are identical.

23. The composition of any one of claims 16-22, wherein oligonucleotides of the plurality are or comprise two or more pharmaceutically acceptable salts.

24. The composition of any one of claims 16-23, wherein each chiral linkage phosphorus in the oligonucleotides of the plurality independently has a diastereomeric purity of about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%.

25. The composition of claim 24, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 90%.

26. The composition of claim 24, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 95%.

27. The composition of claim 24, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 98%.

28. The composition of any one of claims 16-23, wherein the level of oligonucleotides of the plurality in oligonucleotides in the composition that share the constitution of an oligonucleotide of the plurality is about or at least (DS)nc, wherein DS is about 85%-100% (e.g., about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about Page 197 of 20113318736vlAttorney Docket No.: 2010581-166799%, or about 99.5%) and nc is the number of chiral linkage phosphorus.

29. The oligonucleotide of claim 28, wherein DS is about or at least about 90%.

30. The oligonucleotide of claim 28, wherein DS is about or at least about 95%.

31. The oligonucleotide of claim 28, wherein DS is about or at least about 98%.

32. The oligonucleotide of claim 28, wherein DS is about or at least about 99%.

33. The composition of any one of claims 16-23, wherein the level of oligonucleotides of a plurality in oligonucleotides in the composition that share the constitution of an oligonucleotide of the plurality is about or at least about 20%-100%, or is about or at least about 20%-95%, about 30%-90%, about 40%-85%, about 40%-80%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 75%, about 80%, about 85%, or about 90%.

34. The composition of any one of claims 16-33, wherein oligonucleotides of the plurality are sodium salts.

35. The composition of any one of claims 16-34, wherein the composition is a pharmaceutical composition and further comprises a pharmaceutically acceptable carrier.

36. A pharmaceutical composition comprising an oligonucleotide of claim 1 and a pharmaceutically acceptable carrier.

37. The composition of claim 36, wherein the oligonucleotide is a salt.

38. The composition of claim 36, wherein the oligonucleotide is a pharmaceutically acceptable salt.

39. The composition of claim 36, wherein the oligonucleotide is a sodium salt.

40. The composition of claim 36, wherein the oligonucleotide is an ammonium salt.

41. The composition of any one of claims 36-40, wherein the composition comprises two or more pharmaceutically acceptable salts of [moe]([m5C])[Ssp].[moe](T)[n001R].[moe]([m5C])p.[moe](T)[n001R].[moe](G)[Ssp].d(G)[Ssp].d(G)[Rsp]. d(T)[Ssp].d(T)[Rsp].d(G)[Ssp].d(C)[Ssp].d(T)[Ssp].d(G)[Rsp].d(G)[Ssp].d(G)[Ssp].m(U)[Ssp].m(C)[n001R].m(A) [Ssp].m(C) [Ssp].m(U).

42. The composition of any one of claims 36-41, wherein the composition is enriched for the oligonucleotide.

43. The composition of any one of claims 36-41, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%.

44. The composition of claim 43, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 90%.

45. The composition of claim 43, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 95%.

46. The composition of claim 43, wherein each chiral linkage phosphorus independently has a diastereomeric purity of about or at least about 98%.Page 198 of 20113318736vlAttorney Docket No.: 2010581-166747. The composition of any one of claims 36-41, wherein the diastereomeric purity of the oligonucleotide is about or at least about (DS)nc, wherein DS is about 85%-100% (e.g., about or at least about 85%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, or about 99%), and nc is the number of chiral linkage phosphorus in the oligonucleotide.

48. The composition of claim 47, wherein DS is about or at least about 90%.

49. The composition of claim 47, wherein DS is about or at least about 95%.

50. The composition of claim 47, wherein DS is about or at least about 98%.

51. The composition of claim 47, wherein DS is about or at least about 99%.

52. The composition of any one of claims 36-51, wherein the purity of the oligonucleotide is about 20%-100%, or is about or at least about 20%-95%, about 30%-90%, about 40%-85%, about 40%-80%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 75%, about 80%, about 85%, or about 90%.

53. The composition of any one of claims 36-51, wherein the purity of the oligonucleotide is about 20%-100%, or is about or at least about 20%-95%, about 30%-90%, about 40%-85%, about 40%-80%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about 75%, about 80%, about 85%, or about 90%.

54. The composition of any one of claims 35-53, wherein the pharmaceutically acceptable carrier is or comprises a physiologically compatible buffer.

55. The composition of any one of claims 35-54, wherein the pharmaceutically acceptable carrier is or comprises a phosphate buffer.

56. The composition of any one of claims 35-54, wherein the pharmaceutically acceptable carrier is or comprises a saline buffer.

57. The composition of any one of claims 35-53, wherein the pharmaceutically acceptable carrier is or comprises cerebrospinal fluid.

58. The composition of any one of claims 35-53, wherein the pharmaceutically acceptable carrier is or comprises artificial cerebrospinal fluid.

59. A method for reducing level of a HTT transcript or a product thereof in a system, comprising administering or delivering to the system an oligonucleotide or composition of any one of the preceding claims.

60. The method of claim 59, wherein the HTT transcript comprises a CAG repeat expansion.

61. The method of claim 59, wherein the HTT transcript comprises (CAG)₄₀ or above in exon 1.

62. The method of claim 59, wherein the HTT transcript comprises (CAG)?o or above in exon 1.

63. The method of any one of claims 59-62, wherein level of a HTT transcript is reduced.

64. The method of any one of claims 59-63, wherein level of a product encoded by a HTT transcript is reduced.

65. The method of claim 64, wherein the product is a HTT polypeptide.Page 199 of 20113318736vlAttorney Docket No.: 2010581-166766. The method of any one of claims 59-65, wherein the system is or comprises a cell.

67. The method of any one of claims 59-65, wherein the system is or comprises a tissue.

68. The method of any one of claims 59-65, wherein the system is or comprises an organ.

69. The method of any one of claims 59-65, wherein the system is or comprises an animal.

70. The method of any one of claims 59-65, wherein the system is or comprises a mammal.

71. The method of any one of claims 59-65, wherein the system is a human.

72. A method for preventing or treating a condition, disorder or disease, comprising administering or delivering to a subject susceptible thereto or suffering therefrom an oligonucleotide or composition of any one of the preceding claims, wherein the condition, disease or disorder is associated with HTT.

73. A method for treating Huntington’s disease, comprising administering or delivering to a subject suffering therefrom an oligonucleotide or composition of any one of the preceding claims.

74. A method for treating, preventing, delaying onset of, and / or decreasing the severity of a symptom of Huntington’s disease, comprising administering or delivering to a subject suffering therefrom or susceptible thereto an oligonucleotide or composition of any one of the preceding claims.

75. The method of any one of claims 72-74, wherein the subject comprises an expanded CAG repeat region in HTT.

76. The method of any one of claims 72-74, wherein the subject comprises (CAG)₄₀ or above in HTT exon 1.

77. The method of any one of claims 72-74, wherein the subject comprises (CAG)₇₀ or above in HTT exon 1.

78. An oligonucleotide or composition of any one of claims 1-58, for use in a method of any one of claims 59-77.

79. An oligonucleotide or composition of any one of claims 1 -58, for manufacturing a medicament for a method of any one of claims 59-77.

80. Use of an oligonucleotide or composition of any one of claims 1-58 for a method of any one of claims 59-77.

81. Use of an oligonucleotide or composition of any one of claims 1-58 for manufacturing a medicament for a method of any one of claims 59-77.Page 200 of 20113318736vl

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