COMPOSITIONS AND METHODS FOR ADMINISTERING THERAPEUTIC AGENTS

Description

BACKGROUND

[0001] Effective in vivo delivery of active agents such as small molecule drugs, proteins, peptides, and nucleic acids represents a continuing medical challenge. Some active agents are recognized by the immune system, resulting in decreased efficacy. To address this issue, certain active agent formulations have incorporated polymers such as polyethylene glycol which was thought to cloak or mask the agent, thereby reducing its antigenicity and immunogenicity. However, even these "stealth" formulations have their limitations, including an inability to be repeatedly and frequently dosed, for example, over a period of days without loss of activity.

[0002] In addition, some agents or formulations when administered in vivo may interact with one or more cells or factors, potentially interfering with their functions, and ultimately resulting in adverse effects. Such adverse effects may limit the administration frequency and / or administered dose of the agent, or may preclude in vivo use altogether.

[0003] WO2013 / 086373 concerns lipids for delivery of active agents. WO2015 / 058069 concerns compositions and methods for tolerizing cellular systems. WO2015 / 199952 concerns novel lipids for delivery of nucleic acids.SUMMARY

[0004] Based on the disclosure that is contained herein, the present invention provides a lipid nanoparticle (LNP) encapsulating an mRNA coding for a therapeutic protein, wherein the LNP comprises a cationic lipid, a helper lipid, a structural lipid, and a stabilizer, wherein the cationic lipid is an ionizable lipid, wherein the stabilizer is a PEG lipid, and wherein the PEG lipid is a compound of Formula (V-OH): or a pharmaceutically acceptable salt thereof, wherein: r is an integer between 1 and 100, inclusive; and R 5< is optionally substituted C 10-40 alkyl, optionally substituted C 10-40 alkenyl, or optionally substituted C 10-40 alkynyl; and wherein the LNP does not trigger accelerated blood clearance.

[0005] In another aspect, the present invention provides a lipid nanoparticle (LNP) for use in a method of delivering a therapeutic level of a protein of interest to a subject, wherein the LNP is the LNP of the invention, wherein the method comprises administering a first dose and a second dose of the LNP to the subject; and wherein the first dose of LNP does not induce an immune response that promotes accelerated blood clearance (ABC) upon administration of a second dose of LNP.

[0006] The present invention is defined in the independent claims and certain optional features thereof are defined in the dependent claims. In so far as the terms "invention", "example" and "embodiment" are used herein, this will be interpreted in such a way that the only protection sought is for the invention as claimed.

[0007] The present disclosure is based, at least in part, on the discoveries that components of lipid nanoparticles (LNPs) may induce an innate immune response. In some embodiments components of the LNPs, such as phosphatidylcholine, may induce the production of natural IgM and / or IgG molecules, which may be mediated by activation of B1 cells, such as B1a and / or B1b cells. These biological mechanisms may contribute to drug responses caused by LNPs, including accelerated blood clearance (ABC) and dose-limiting toxicity such as acute phase response (APR) and complement activation-related pseudoallergy (CARPA). Both B1a cells and platelets express CD36, which can bind phosphatidylcholine.

[0008] The activation of B1 cells and platelets by LNPs may be mediated by activation of the CD36 receptor by a component in the LNPs such as phosphatidylcholine. Additionally, the PEG-lipid on the LNPs may contribute to the production of natural IgM and / or anti-PEG IgG and IgM. Accordingly, provided herein are methods and compositions for delivering LNPs to a subject without promoting the same degree of LNP-related drug responses as noted herein by using LNPs that do not trigger an innate immune response characterized by natural IgM production, natural IgG production, anti-PEG IgM, anti-PEG IgG, B1a cell activation, B1b cell activation, pDC cell activation and / or platelet aggregation and / or activation, and / or using secondary agents, in particular, pharmacological agents, that inhibit the production of this innate immune response, as well as suppress the downstream signaling pathways leading to the LNP-related drug responses.

[0009] This disclosure provides, in part, novel lipid nanoparticles (LNP) and LNP formulations that are less susceptible to recognition and thus clearance, by the immune system. The LNP provided herein have surprisingly improved clearance and in some instances, toxicity profiles. While not intending to be bound by any particular mechanism or theory, the improved clearance profiles are believed to have reduced recognition by and / or binding to certain immune cells and less overall effect on those and other immune cells and factors. More specifically, certain of the LNPs provided herein have no or low binding to B1a and / or B1b cells, B1a and / or B1b activating activity, pDC activating activity, platelet aggregating activity, and / or platelet activating activity. This activity may be due at least in part to the components of the LNP, or an agent that inhibits immune responses induced by the LNP components. Such an agent may be incorporated within the LNP administered or or formulated separately.

[0010] Also provided in this disclosure are compounds and compositions, including formulations, that modulate immune responses to administered nanoparticles such as LNP. Also provided herein are methods of use of such compounds and compositions, particularly relating to immune modulation in vivo. Also provided are methods of use of LNPs together with certain classes of secondary agents, including for example use of LNPs in subjects that have been co-medicated, e.g., pre-medicated with certain secondary agents. Also provided are pre-administration and / or pre-treatment screening methods that identify patients that respond to LNP administration and optionally classify such patients according the degree of their response. Identifying such subjects may lead, in some instances, to a modified treatment regimen.

[0011] Certain of the LNPs provided herein comprise a cationic lipid, a helper lipid, a structural lipid, and a stabilizer which may or may not be provided conjugated to another lipid.

[0012] The cationic lipid may be but is not limited to DLin-DMA, DLin-D-DMA, DLin-MC3-DMA, DLin-KC2-DMA and DODMA. The cationic lipid may be an ionizable lipid.

[0013] The structural lipid may be but is not limited to a sterol such as for example cholesterol.

[0014] The helper lipid is an amphiphilic surface active lipid, or surfactant. In some embodiments it is a non-cationic lipid The helper lipid may comprise at least one non-polar chain and at least one polar headgroup moiety. A helper lipid may also be referred to as a complementary lipid i.e. the lipid functions to "complement" the amino lipid and increase the fusogenicity of the bilayer to help endosomal escape. In some embodiments the non-polar chain is a lipid. In other embodiments it is a fatty acid of at least 8C. In exemplary embodiments, the helper lipid is non-naturally occurring (e.g., not naturally occurring in human subjects) or is exogenous.

[0015] Certain of the LNPs lack any phosphatidyl choline (PC) lipids (i.e., are free of phosphatidyl choline (PC)). Certain of the LNPs provided herein lack specific phosphatidyl choline lipids such as but not limiting to DSPC. Certain of the LNPs comprise a phosphatidyl choline analog, such analogs comprising modified head groups (e.g., a modified quaternary amine head group), modified core group, and / or modified lipid tail group. Such analogs may comprise a zwitterionic group that is a non-PC zwitterionic group. The helper lipid may be a lipid of any one or any combination of Formulae I, I-a, I-b, I-b-1. I-b-2. I-b-3. I-b-4, I-c, I-c-1, I-c-2, I-c-3, or II as provided herein.

[0016] Certain LNPs comprise other helper non-cationic lipids including for example oleic acid or oleic acid analogs. The helper lipid may be a lipid of Formula IV as provided herein.

[0017] The stabilizer may be polyethylene glycol (PEG). PEG may be conjugated to a lipid and thus may be provided as PEG-c-DOMG or PEG-DMG, for example. The stabilizer, whether provided in a conjugated or an unconjugated form, may comprise 1.5 mol% of the LNP, or it may comprise less than 0.5 mol% of the LNP. For example, it may comprise less than 0.4 mol %, less than 0.3 mol %, less than 0.2 mol%, or less than 0.1 mol %.

[0018] The LNP may comprise a PEGylated lipid of Formula III, including Formulae III-OH, III-a-1, III-a-2, III-b-1, IIII-b-2, III-b-1-OH, III-b-2-OH, V, V-OH.

[0019] Certain of the LNPs provided herein comprise no or low levels of PEGylated lipids, including no or low levels of alkyl-PEGylated lipids, and may be referred to herein as being free of PEG or PEGylated lipid. Thus, some LNPs comprise less than 0.5 mol% PEGylated lipid. In some instances, PEG may be an alkyl-PEG such as methoxy-PEG. Still other LNPs comprise non-alkyl-PEG such as hydroxy-PEG, and / or non-alkyl-PEGylated lipids such as hydroxy-PEGylated lipids.

[0020] The PEGylated lipid may be a Cmpd420, a Cmpd396, a Cmpd394, Cmpd397, Cmpd395, Cmpd417, Cmpd418, or Cmpd419.

[0021] In some instances, the LNP may comprise about 50 mol %, 10 mol % helper lipid, 1.5 mol % PEGylated lipid, and 38.5 mol % structural lipid.

[0022] In some instances, the LNP may comprise about 50 mol %, 10 mol % helper lipid, less than 0.5 mol% PEGylated lipid, and 39.5 mol% structural lipid.

[0023] In some embodiments, the stabilizer is a non-PEG moiety such as an XTEN peptide that may or may not be conjugated to a lipid. The XTEN peptide is capable of forming a hydrated shell around the LNP due to its hydrophilic nature. It further serves to increase the half-life of the LNP, compared to an LNP lacking (or free of) any stabilizer. Unlike PEG, however, it is biodegradable and has been reported to be non-immunogenic. The X TEN peptide may have an amino acid sequence of MAEPAGSPTSTEEGTPGSGTASSSPGSSTPSGATGSPGASPGTSSTGS (SEQ ID NO:1) or MAEPAGSPTSTEEGASPGTSSTGSPGSSTPSGATGSPGSSTPSGATGS (SEQ ID NO:2). Other XTEN amino acid sequences are known in the art, including for example those reported in U.S. Patent No. 9,062,299. Examples of XTEN conjugated lipids include but are not limited to Cmpd431, and Cmpd432 and Cmpd433. Click chemistry may be used to conjugate the XTEN peptide to the lipid.

[0024] In some embodiments, the stabilizer is a non-PEG moiety such as a PAS peptide. A PAS peptide is a peptide comprising primarily if not exclusively proline, alanine and serine. Like PEG and XTEN peptides, the PAS peptide is capable of forming a hydrated shell around the LNP. It too serves to increase the half-life of an LNP, compared to an LNP lacking (or free of) a stabilizer. Unlike XTEN peptides, however, PAS peptides tend to be neutral in charge, and thus at least in this respect more similar to PEG. The PAS peptide may have an amino acid sequence of SAPSSPSPSAPSSPSPASPSSAPSSPSPSAPSSPSPASPSSAPSSPSPSAPSSPSPASPS (SEQ ID NO:3 or AASPAAPSAPPAAASPAAPSAPPAAASPAAPSAPPAAASPAAPSAPPA (SEQ ID NO:4). Other PAS amino acid sequences are known in the art, including for example, those reported in WO 2008155134.

[0025] The disclosure contemplates LNPs having any combination of the foregoing characteristics. Such LNPs may be further characterized as having reduced binding to B1a cells and / or reduced B1a cell activation activity. Additionally or alternatively, they may be further characterized as having reduced platelet aggregation activity, which may be indicated as reduced platelet activation activity.

[0026] This disclosure further contemplates that such LNPs may be used in vivo to deliver an agent, such as a protein or a nucleic acid, without triggering accelerated blood clearance (ABC). Thus, such LNPs can be administered to a subject repeatedly and within short time periods without risk of enhanced clearance by the immune system, as has been previously reported for a variety of administered agents including lipid formulated agents. Thus, the LNPs and more importantly their cargo can be administered more frequently, and effectively at higher doses over these short time periods, than was previously possible.

[0027] Even more surprisingly, certain of these LNPs also demonstrate reduced toxicity upon administration. Again, while not intending to be bound by any particular mechanism or theory, this is believed to result from the reduced platelet aggregation activity of these LNPs. This inability or reduced ability to aggregate platelets reduces the likelihood and severity of coagulopathy-related toxicity that has been observed following LNP administration in vivo.

[0028] It was wholly unexpected that certain LNPs would have the dual benefit of reduced susceptibility to ABC and reduced toxicity in vivo. As a result, these LNPs allow for higher doses of encapsulated agent to be administered to a subject, due in part to the reduced toxicity profile of their encapsulating LNP. The LNPs also lead to a longer half-life for the LNPs and thus their cargo, due in part to their reduced susceptibility to ABC. This results in higher and more stable levels of cargo between administrations. Moreover, in the case of cargo requires repeated frequent administration, the LNPs provided herein facilitate such administration. This serves to increase the efficacy of certain agents by allowing more frequent dosing than may currently be possible. This also serves to render useful other agents that may have not been used previously in vivo due to these restrictions.

[0029] This disclosure further provides other novel formulations and methods of use of LNPs, including LNP formulations. Specifically, provided herein are methods of use of LNPs and LNP formulations together with anti-platelet agents including but not limited to platelet aggregation inhibitors. This disclosure contemplates that such agents may be administered to a subject prior to and / or substantially simultaneously with, and / or even after administration of the LNP. Thus, such agents may be formulated together with the LNP or they may be separately formulated but administered together, via the same route, and / or at the same or substantially the same time. Significantly, pre-medication or co-medication of a subject with these anti-platelet agents results in reduced toxicity, including coagulopathy-related toxicity, and in a lower and less severe incidence of ABC. According to certain embodiments, subjects may be pre-medicated or co-medicated with a combination of secondary agents including platelet aggregation inhibitors, anti-histamines, and NSAIDS or COX enzyme inhibitors. Certain secondary agents that may he used have dual functionality (i.e., they are able to inhibit platelet aggregation, in whole or in part, and also have a general anti-inflammatory effect). One such example is aspirin.

[0030] A lipid nanoparticle (LNP) encapsulating an mRNA encoding a protein is provided in some aspects of the invention. The LNP has a cationic lipid, a non-cationic helper lipid comprising at least one fatty acid chain of at least 8C and at least one polar head group moiety, and wherein the helper lipid is not a phosphatidyl choline (PC), a PEG lipid, and a sterol. In some aspects the LNP further comprises an agent that inhibits immune responses by the LNP. In other aspects the non-cationic helper lipid is a zwitterionic non-cationic helper lipid, a DSPC analog, oleic acid, an oleic acid analog, or a 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) substitute.

[0031] In certain embodiments, non-cationic lipids useful in the present invention are DSPC analogs wherein the phosphocholine moiety is replaced by a different zwitterionic group. In certain embodiments, the different zwitterionic group is not a phosphocholine group. In certain embodiments, a non-cationic lipid useful in the present invention is a compound of Formula (II ). Provided herein are compounds of Formula (II): or a salts thereof wherein: Z is a zwitterionic moiety, wherein the zwitterionic moiety is not of the formula: m is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; A is of the formula: each instance of L 2< is independently a bond or optionally substituted C 1-6 alkylene, wherein one methylene unit of the optionally substituted C 1-6 alkylene is optionally replaced with -O-, -N(R N< )-, -S-, -C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -C(O)O-, -OC(O)-, - OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, or -NR N< C(O)N(R N< )-; each instance of R 2< is independently optionally substituted C 1-30 alkyl, optionally substituted C 1-30 alkenyl, or optionally substituted C 1-30 alkynyl; optionally wherein one or more methylene units of R 2< are independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-, - NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(O)N(R N< )-, - NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-, NR N< C(=NR N< )-, - NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-, - OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-, - S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, -N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, -OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group; Ring B is optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, or optionally substituted heteroaryl; and p is 1 or 2.

[0032] In certain embodiments, Z is an amino acid or a derivative thereof. In certain embodiments, Z is of one of the following formulae: wherein R o< is hydrogen, optionally substituted alkyl or an oxygen protecting group. In certain embodiments, a compound of Formula (II) is of one of the following formulae: or a salt thereof.

[0033] In certain embodiments, a compound of Formula (II ) is of one of the following formulae: or a salt thereof.

[0034] For example, in certain embodiments, a compound of Formula (II ) is one of the following: or salts thereof.

[0035] Non-cationic lipids useful in the present invention also include analogs of oleic acid. As described herein, an oleic acid analog can comprise a modified oleic acid tail, a modified carboxylic acid moiety, or both. In certain embodiments, an analog of oleic acid is a compound of Formula (IV) . Provided herein are compounds of Formula (IV): or a salt thereof, wherein: R 4< is optionally substituted, C 10-40 alkyl; optionally substituted, C 10-40 alkenyl; optionally substituted, C 10-40 alkynyl; wherein at least one methylene group of R 4< is independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, - OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, - C(-NR N< )N(R N< )-, -NR N< C(-NR N< )-, -NR N< C(=NR N< )N(R N< )-, -C(S)-. -C(S)N(R N< )-, - NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-, -OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, - S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-, -S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, - N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, - OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; and each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group.

[0036] In certain embodiments, the compound of Formula (IV ) is one of the following: or salts thereof.

[0037] In certain embodiments, an oleic acid analog is a compound wherein the carboxylic acid moiety of oleic acid replaced by a different group. In certain embodiments, an oleic acid analog useful in the present invention is one of the following: or salts thereof.

[0038] Examples of non-cationic lipids include, but are not limited to. the following: and

[0039] A lipid nanoparticle (LNP) encapsulating an mRNA encoding a protein is provided in some aspects of the invention. The LNP has a cationic lipid, a non-cationic helper lipid comprising at least one fatty acid chain of at least 8C and at least one polar head group moiety, a PEG lipid, and a sterol. In some aspects the LNP further comprises an agent that inhibits immune responses by the LNP. In some embodiments the PEG lipid is an alkyl-PEGylated lipids, non-alkyl-PEG such as hydroxy-PEG, a non-alkyl-PEGylated lipid such as hydroxy-PEGylated lipid, a Cmpd420, a Cmpd396, a Cmpd394, Cmpd397, Cmpd395, Cmpd417, Cmpd418, or Cmpd419, Cmpd421, Cmpd422, or wherein the PEG lipid contains less than 0.5% molar ratio of PEG lipid to the other components. In certain embodiments, a PEG lipid useful in the present disclosure is a compound of Formula (III ). Provided herein are compounds of Formula (III ): or salts thereof, wherein: R 3< is -OR o< ; R o< is hydrogen, optionally substituted alkyl, or an oxygen protecting group; r is an integer between 1 and 100, inclusive; L 1< is optionally substituted C 1-10 alkylene, wherein at least one methylene of the optionally substituted C 1-10 alkylene is independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -O-, -N(R N< )-, -S-, -C(O)-, -C(O)N(R N< )-, - NR N< C(O)-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, or - NR N< C(O)N(R N< )-; D is a moiety obtained by click chemistry or a moiety cleavable under physiological conditions; m is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; A is of the formula: each instance of L 2< is independently a bond or optionally substituted C 1-6 alkylene, wherein one methylene unit of the optionally substituted C 1-6 alkylene is optionally replaced with -O-, -N(R N< )-, -S-, -C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -C(O)O-, -OC(O)-, - OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, or -NR N< C(O)N(R N< )-; each instance of R 2< is independently optionally substituted C 1-30 alkyl, optionally substituted C 1-30 alkenyl, or optionally substituted C 1-30 alkynyl; optionally wherein one or more methylene units of R 2< are independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene. -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-, - NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(O)N(R N< )-, - NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-, -NR N< C(=NR N< )-, - NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-, - OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-, - S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, -N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -. -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, -OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group; Ring B is optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, or optionally substituted heteroaryl; and p is 1 or 2.

[0040] In certain embodiments, the compound of Fomula (III) is a PEG-OH lipid (i.e., R 3< is -OR o< , and R o< is hydrogen). In certain embodiments, the compound of Formula (III ) is of Formula (III-OH ): or a salt thereof.

[0041] In certain embodiments, D is a moiety obtained by click chemistry (e.g., triazole). In certain embodiments, the compound of Formila (III ) is of Formula (III-a-1 ) or (III-a-2 ): or a salt thereof.

[0042] In certain embodiments, the compound of Formula (III ) is of one of the following formulae: or a salt thereof, wherein s is 0, 1, 2, 3, 4, 5, 6. 7, 8, 9, or 10.

[0043] In certain embodiments, the compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0044] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0045] In certain embodiments, a compound of Formula (III) is of one of the following formulae: or a salt thereof.

[0046] In certain embodiments, D is a moiety cleavable under physiological conditions (e.g., ester, amide, carbonate, carbamate, urea). In certain embodiments, a compound of Formula (III ) is of Formula (III-b-1 ) or (III-b-2 ): or a salt thereof.

[0047] In certain embodiments, a compound of Formula (III ) is of Formula (III-b-1-OH ) or (III-b-2-OH ): or a salt thereof.

[0048] In certain embodiments, the compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0049] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0050] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0051] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or salts thereof.

[0052] In certain embodiments, a PEG lipid useful in the present disclosure is a PEGylated fatty acid. In certain embodiments, a PEG lipid useful in the present disclosure is a compound of Formula (V ). Provided herein are compounds of Formula (V): or a salts thereof, wherein: R 3< is-OR o< ; R o< is hydrogen, optionally substituted alkyl or an oxygen protecting group; r is an integer between 1 and 100, inclusive; R 5< is optionally substituted C 10-40 alkyl, optionally substituted C 10-40 alkenyl, or optionally substituted C 10-40 alkynyl; and optionally one or more methylene groups of R 5< are replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, - C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-, - OC(O)N(R N< )-, -NRC(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-, - NR N< C(=NR N< )-, -NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(RN)-, NR N< C(S)-, - NR N< C(S)N(R N< )-, -S(O)-, -OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-. - OS(O) 2 O-, -N(R N< )S(O)-, -S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, - N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, - OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; and each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group.

[0053] In embodiments of the invention, the compound of Formula (V) is of Formula (V-OH ): or a salt thereof.

[0054] In certain embodiments, a compound of Formula (V) is of one of the following formulae: or a salt thereof.

[0055] In other aspects the non-cationic helper lipid is a zwitterionic non-cationic helper lipid, a lipid that is not a phosphatidyl choline (PC), a DSPC analog, oleic acid, an oleic acid analog, or a 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) substitute.

[0056] In some embodiments the agent that inhibits immune responses by the LNP comprises a miR binding site. In other embodiments the miR binding site is selected from miR 126, miR 155, and miR 142 3p. The miR binding site is incorporated into a mRNA in some embodiments. In other embodiments the miR binding site is separate from the mRNA.

[0057] In some embodiments the agent that inhibits immune responses by the LNP comprises an mRNA comprising a miR binding site. In various embodiments, the mRNA comprises 1-4, one, two, three or four miR binding sites, wherein at least one of the miR binding sites is a miR-126 binding site. In one embodiment, the mRNA, comprises at least two microRNA binding sites, wherein at least one of the microRNA binding sites is a miR-126 binding site. In one embodiment, the mRNA, e.g., mmRNA, comprises a miR-126 binding site and a second microRNA binding site for a miR selected from the group consisting of miR-142-3p, miR-142-5p, miR-146-3p, miR-146-5p, miR-155, miR-16, miR-21, miR-223, miR-24 and miR-27. In another embodiment, the mRNA, comprises a miR-126 (e.g., miR-126-3p) binding site and a miR-142 (e.g., miR-142-3p) binding site. A miR referred to by number herein can refer to either of the two mature microRNAs originating from opposite arms of the same pre-miRNA (e.g., either the 3p or 5p microRNA). All miRs referred to by number herein are intended to include both the 3p and 5p arms / sequences. It has now been discovered that incorporation of at least one microRNA binding site for a microRNA expressed in immune cells (e.g., miR-126, miR-142, miR-155 and combinations thereof) into an mRNA construct can reduce or inhibit ABC when the lipid-comprising compound or composition comprising the mRNA is administered to a subject. In one embodiment, the mechanism of action of the miRNA binding site(s) is a microRNA "sponge", wherein the miRNA binding site(s) in the construct or LNP "soaks up" microRNAs that bind to the binding site(s).

[0058] The DSPC analog may have a modified head group that is a modified quaternary amine head group, a modified core group, or a modified lipid tail group. In some embodiments. The PEG lipid in other embodiments contains at least 0.0001%, at least 0.0005%, at least 0.001%, at least 0.005%, at least 0.01%, at least 0.05%, at least 0.1%, at least 0.15%, at least 0.2%, at least 0.25%, at least 0.3%, at least 0.35%, at least 0.4%, at least 0.45%, and less than 0.5% molar ratio of PEG lipid to the other components.

[0059] In some embodiments the LNP may have a molar ratio of about 45-65% cationic lipid, about 0.15-15% PEG lipid, about 15-45% cholesterol and about 5-25% non-cationic helper lipid or a molar ratio of about 55% cationic lipid, about 2.5% PEG lipid, about 32.5% cholesterol and about 10% non-cationic lipid.

[0060] In other embodiments the cationic lipid is selected from DLin-DMA, DLin-D-DMA, DLin-MC3-DMA, DLin-KC2-DMA or DODMA. In other embodiments the cationic lipid is selected from the lipid Cmpd numbers provided herein.

[0061] The disclosure provides a PEG lipid comprising a compound of Formula (V): or a salts thereof, wherein: R 3< is-OR o< ; R o< is hydrogen, optionally substituted alkyl or an oxygen protecting group; r is an integer between 1 and 100, inclusive; R 5< is optionally substituted C 10-40 alkyl, optionally substituted C 10-40 alkenyl, or optionally substituted C 10-40 alkynyl; and optionally one or more methylene groups of R 5< are replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, - C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-, - OC(O)N(R N< )-, -NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-, - NR N< C(=NR N< )-, -NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-, - NR N< C(S)N(R N< )-, -S(O)-, -OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-, - OS(O) 2 O-, -N(R N< )S(O)-, -S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, - N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, - OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; and each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group.

[0062] In embodiments of the invention the compound of Formula (V ) is of Formula (V-OH): or a salt thereof.

[0063] In other embodiments the compound of Formula (V) is of one of the following formulae: or a salt thereof.

[0064] In yet other embodiments the compound of Formula (V) is: or a salt thereof.

[0065] These and other embodiments and aspects will be discussed in greater detail herein.BRIEF DESCRIPTION OF DRAWINGS

[0066] The following Figures are provided in and grey scale. FIG. 1: Phycoerythrin (PE) fluorescence of CD3+ T cells and CD19+ B cells following incubation with PE- LNP, PE+ LNP or medium alone. The data show uptake of LNPs by splenic B cells but not T cells under ex vivo culture conditions. FIGs. 2A-2B: Phycoerythrin (PE) fluorescence of CD3+ T cells and CD19+ B cells as a function of time of incubation with PE- LNP, PE+ LNP or medium alone. The data show LNP uptake by B cells but not T cells occurs rapidly in these ex vivo culture conditions. FIG. 3: EGFP fluorescence of CD19+ cells as a function of time of incubation with PE+ LNP comprising EGFP mRNA. No expression of EGFP by B cells is observed at any time point, despite massive LNP uptake by those cells. FIGs. 4A-4B: hEPO concentration and anti-PEG IgM levels in vivo following administration of first, second and third doses (hEPO) and first and second (IgM) of LNP carrying hEPO mRNA cargo into CD-1 non-splenectomized (CD-1) and splenectomized mice. FIG. 5: PE-Rhodamine fluorescence in CD19+ circulating B cells after incubation for 2. 4, 6 and 24 hours with PE+ and PE- LNP FIGs. 6A-6B: LNP uptake (FIG. 6A) and EGFP expression (FIG. 6B) by circulating B cells as a function of incubation time. FIG. 7: CD86 expression in splenic and circulating B cells following incubation with PE- and PE+ LNP. Splenic and circulating B cells that take up LNPs are activated. FIG. 8: CD86 expression in splenic and circulating B cells that take up or fail to take up PE+ LNPs. Splenic and circulating B cells that take up LNPs are activated, as evidenced by increased CD86 expression. FIG. 9: CD86 expression as a function of LNP uptake by splenic B cells at various incubation times. FIG. 10: IL-6 and TNF-alpha secretion by B cells incubated with PE+ and PE- LNP for 24 hours. FIGs. 11A-11B: Empty PE+ LNP uptake by CD19+ B cells at 24 hours (FIG. 11A) and the time course at 4 and 24 hours (FIG. 11B). FIGs. 12A-12B: CD86 expression in B cells that have taken up empty PE+ LNP (FIG. 12A). Splenic B cells are activated by empty LNPs in a dose dependent manner. IL-6 and TNF-alpha secretion by B cells incubated with empty PE+ LNP (FIG. 12B). FIGs. 13A-13D: Uptake and cytokine secretion by B cells from wild type (WT), ApoE deficient, and LDL receptor deficient mice in PE+ LNPs (FIG. 13A) and PE- LNPs (FIG. 13B). The percentage of CD19+ PE+ cells (FIG. 13C) and cytokine levels in pg / ml (FIG. 13D) are also given. FIG. 14: LNP uptake following pre-incubation of B cells with free PEG or anti-PEG IgG. FIG. 15: Uptake of LNPs comprising PEG or PEG-OH or lacking PEG (PEGless) by B cells. FIG. 16: Uptake of LNPs comprising PEG or PEG-OH or lacking PEG (PEGless) by B cells. FIG. 17: CD86 expression in B cells incubated with PEG-less LNP or PEG-OH LNP, as a function of LNP uptake. FIG. 18: LNP uptake as a function of phospholipid content of the LNP. FIG. 19: LNP uptake as a function of phospholipid and PEG content of the LNP in CD19+ B cells and CD5+ B cells. FIG. 20: LNP uptake by CD19+, CD19+CD5+ or CD19+CD5- B cells as a function of phospholipid and PEG content. FIG. 21: EGFP expression in non-conventional T (CD3-) and B (CD19-) cells from the spleen 1 and 4 hours after administration of LNPs comprising DMG-PEG or PEG-OH and PEGless LNPs. FIGs. 22A-22B: LNP uptake by B cells in vivo as a function of phospholipid and PEG content. FIGs. 23A-23E: CD86 expression levels in B cells after injection of LNPs comprising DMG-PEG (FIG. 23A) or Cmpd418 (FIG. 23B), or PEGless LNP (FIG. 23C). CD86 expression level was assessed at I hour (FIG. 23D) and 4 hours (FIG. 12E) after injection of LNP. FIGs. 24A-24B: Uptake of PE+ LNP by B cells in vivo 1 hour (FIG. 24A) and 4 hours (FIG. 24B) after injection of LNP comprising DMG-PEG or PEG OH or PEGless LNPs. FIG. 25: LNP uptake in B cells as a function of DMG-PEG content in LNP (intermediate content study). FIG. 26: B cell activation after LNP uptake as a function of DMG-PEG content in LNP. The data are presented in sets of 4 bars. the four bars in each set representing LNP PE negative, LNP-PE positive low, LNP-PE positive intermediate, and LNP-PE positive high, from left to right, respectively. Thus, the bars represent populations of cells that have associated or taken up an increasing amount of LNPs. FIG. 27: LNP uptake in B cells as a function of DMG-PEG content in LNP (low content study). FIGs. 28: PE+ staining of CD19+ B cells contacted with Cmpd395, Cmpd404, and oleic acid comprising LNPs. FIGs. 29A-29B: B cell activation measured through an increase in activated B cell population (CD19+CD86+CD69+). FIG. 29A shows B cell activation as a function of DMG-PEG mol % without Imiquimod and FIG. 29B shows B cell activation as a function of DMG-PEG mol % with Imiquimod. FIGs. 30A-30B: Pro-inflammatory cytokine release (IFN-γ in FIG. 30A, TNF-α in FIG. 30B) in an ex vivo human B cell culture as a function of DMG-PEG mol % in the presence or absence of Imiquimod. FIGs. 31A-31D: Phospholipid designs of helper lipids that are analogs and substitutes of phosphatidyl choline (PC) and DSPC. The modifications reduce association, recognition for example by receptors, and / or uptake of LNP through for example modifying the PC head group (FIG. 31A), the PC core (FIG. 31B), or through reducing the planarity of the lipid (FIG. 31C). An oleic acid variant is also provided (FIG. 31D). FIGs. 32A-32C: Examples of PEGylated lipids comprising short lipid tails, a click linker, and a hydroxy (OH) PEG end group. FIG. 32A shows Cmpd394, Cmpd395, Cmpd396, and Cmpd397. FIG. 32B shows Cmpd398 and Cmpd399. FIG. 32C shows Cmpd400-403. FIG. 33: Anti-PEG or anti-DSPC IgM response measured by flow cytometry (beads) 96 hours after administration of the second dose. The IgM responses against DSPC or PEG are measured identically when beads are used alone or together. PEG DMG, PEG DSPE or Cmpd430 LNPs induced anti-LNP responses. Anti-PEG IgM and anti DSPC IgMs were both observed suggesting that the IgM response is a natural IgM response. FIG. 34: Anti-PEG IgM measured by ELISA and anti-PEG or anti-DSPC IgM measured by flow cytometry (beads) 96 hours after administration of the second dose. The anti-PEG IgMs measured by ELISA and beads are similar and no significant differences were detected. FIG. 35: LNP association with platelets as a function of time and LNP composition. The percent of LNP associated with platelets (as indicated by phycoerythrin (PE) fluorescence) is shown at three time points (15, 60 and 240 minutes) after administration of PBS, DMG-PEG containing LNP, PEG-OH containing LNP, and PEGless LNP (left to right for each time point). These experiments were performed on purified platelets harvested from the subject at the various time points shown. FIG. 36: Platelet activation as a function of LNP composition. Platelet activation (as indicated by expression of platelet activation marker CD62P (MFI)) was measured at three time points (15, 60 and 240 minutes) after administration of PBS, DMG-PEG LNP, PEG-OH LNP, and PEGless LNP (left to right). FIGs. 37A-37B: Presence of B220+ B cells and F4 / 80+ macrophages in platelet aggregates in vivo as a function of time and LNP composition. Percent of B cells (as indicated by B220+ staining, FIG. 37A) and percent of macrophages (as indicated by F4 / 80+ staining, FIG. 37B) at three time points (15, 60 and 240 minutes) after administration of PBS, DMG-PEG LNP, PEG-OH LNP, and PEGless LNP (left to right), is shown. FIG. 38: In vitro activation of platelets as assessed by upregulation of CD31 and CD62P activation markers, after contact with LNPs. FIGs. 39A-39D: In vitro activation of platelets, as indicated by increased CD31 expression relative to control (medium), at 10 minutes (FIG. 39A), 30 minutes (FIG. 39B), 60 minutes (FIG. 39C), and 120 minutes (FIG. 39D) after administration of medium, LPS and LNP comprising DSPC. FIGs. 40A-40B: In vitro platelet aggregation using a whole blood assay. Aggregated cells were collected and gated based on CD41 expression (first column), high forward scatter and side scatter (second column) and F4 / 80 (y-axis) and CD11b (x-axis) expression (third column) after contact with medium (first row), LPS (second row) and DSPC LNP (third row). Platelet aggregates were isolated based on CD41+ expression and high FCS and high SSC, as shown in the second column for FIG. 40A. Percent of aggregated cells that are CD11b+ F4 / 80+ double positive after administration of medium, LPS, and DSPC LNP (from left to right) is shown (FIG. 40B). FIGs. 41A-41B: In vitro platelet aggregation with B cells (CD19+) and macrophages (CD11b+ and F4 / 80+) after incubation of whole blood with medium, LPS and DSPC LNP (from left to right) for 30 minutes (FIG. 41A) and 120 minutes (FIG. 41B). FIGs. 42A-42C: In vitro platelet aggregation with macrophages (FIG. 42A and 42B) and B cells (FIG. 42C) after incubation of whole blood with medium, LPS, and DSPC LNP (from left to right) for 30 minutes and 120 minutes. FIGs. 43A-43B: Upregulation of platelet activation markers CD31 (FIG. 43A) and CD62P (FIG. 43B) after incubation of platelets with medium (control), DSPC LNP, DOPC LNP, DOPG LNP, DMG-PEG LNP, and LPS (from left to right) in vitro, for 0, 10, 30 and 60 minutes, as measured by flow cytometry. FIGs. 44A-44B: Upregulation of activation markers CD31 (FIG. 44A) and CD62P (FIG. 44B) after incubation of platelets in vitro with medium (control), DSPC LNP, DOPC LNP, DOPG LNP, DMG-PEG LNP and LPS, for 0, 10, 30 and 60 minutes, as measured by flow cytometry. FIG. 45: Model of the effect of LNPs on platelets. DMG-PEG LNP physically associate with and activate platelets. DSPC LNP do not physically associate with platelets, but nevertheless are able to activate platelets. Both LNP types cause platelets to aggregate with concomitant recruitment of B cells and macrophages. PEG-OH and PEGless LNPs do not detectably associate with platelets, suggesting a role of the DMG-PEG in the LNP-platelet association. Even in the absence of DMG-PEG, however there is platelet activation, suggesting an interaction between platelets and the phospholipid component, and in particular the PC head group, in the LNP. FIG. 46A-46B: B1a and B1b cells require the spleen. FIG. 46A shows B1a (top) and B2b (bottom) cell levels following splenectomy or a sham operation. FIG. 46B shows B1a (to) and B2b (bottom) antibody levels following splenectomies. B1b cells lose the ability to secrete antibody. FIG. 47: Reticulocyte counts in intact and splenectomized non-human primates (NHPs). FIG. 48: Hematocrit is maintained in splenectomized NHPs. FIGs. 49A-49D: NHP splenectomy study results. FIGs. 49A-49B show the area under the curve (AUC) results from hEPO-mRNA-MC3 (FIG. 49A) and hEPO (FIG. 49B). C max values for hEPO-mRNA-MC3 (FIG. 49C) and hEPO (FIG. 49D) are also presented. FIGs. 50A-50B: Suppression of complement activation in splenectomized NHPs as demonstrated by levels of complement activation indicators, C3a (FIG. 50A) and C5b9 (FIG. 50B). FIGs. 51A-51B: Cytokine expression in splenectomized NHPs. Levels of IL-6 (FIG. 51A) and IL-10 (FIG. 51B) are given. FIGs. 52A-52B: Anti-PEG IgM (FIG. 52A) and anti-PEG IgG (FIG. 52B) levels are greatly reduced in the absence of spleen. FIGs. 53A-53B is a set of graphs depicting anti-PEG IgM production following administration of LNP formulations. FIG. 54 is a schematic depicting the replacement of a phospholipid with a different zwitterionic group. FIGs. 55A -55B are a set of graphs depicting Luc mRNA expression (FIG. 55A) and B cell activation (FIG. 55B) following administration of LNP formulations in CD-1 mice. CD-1 mice were administered 0.05 mg / kg Luc mRNA and Luc expression was measured six hours later. FIGs. 56A-56E depicts effects of LNP formulation on Luc expression and B cell activation. FIG. 56B is a graph depicting CD86 expression (B cell activation) and FIG. 56C is a graph depicting expression levels of Luc as measured by total flux. The structures are shown in FIGs. 56A, 56D, and 56E. FIGs. 57A-57C depicts the effects of various LNP formulations on B cells and platelets. FIG. 57A is a graph depicting activated B-cell frequencies 24 hours post dose. FIG. 57B is a graph depicting aggregation of platelets 15 minutes post dose. FIG. 57C is a graph depicting recruitment of cells in platelet aggregate. FIGs. 58A-58B depicts the positive effects of oleic acid in an LNP. FIG. 58A depicts levels of luciferase expression as measured by total flux 6 hours after delivery to CD-1 mice. FIG. 58B depicts in vivo B-cell activation in mouse splenocytes 24 hours following the adm inistration. FIG. 59 is a graph depicting hEPO concentration over time. An improved margin of expression with a particle of the invention in contrast to MC3 was demonstrated with chemically modified mRNA. FIGs. 60A-60C is a set of graphs depicting improved immune activation profile with chemically modified mRNA in LNP formulations of the invention. FIG. 60A is a graph depicting in vivo B-cell activation 24 hours following administration of the hEPO loaded particles or PBS. FIG. 60B is a graph depicting in IL-6 concentration 6 hours following administration of the hEPO loaded particles or PBS. FIG. 60C is a graph depicting IP-10 concentration 6 hours following administration of the hEPO loaded particles or PBS. FIG. 61 is a graph depicting LNP Uptake by B cells as measured by percent PE+ CD19+ B cells. FIG. 62 is a graph depicting B cell activation by LNPs as measured by CD86 expression on D cells. FIGs. 63A-63B are a set of graphs depicting the amount of PEG IgM produced 96 hours after a second dose of LNP (FIG. 63A) or 96 hours after a third dose of LNP (FIG. 63B). FIG. 64 is a graph depicting hEPO Expression 6 hours following once weekly administration by IV of hEPO mRNA - LNP formulations at weeks 1,2,3, and 4. FIG. 65 is a graph depicting anti-PEG IgM production 96 hours following a third dose of hEPO mRNA - LNP formulations. FIG. 66 is a graph depicting data from a single dose study of LNP having various phospholipids with different headgroups injected by IV in CD-1 Mice. Each phospholipid is measured at three time points (3, 6, and 24 hrs) following injection. Phospholipid structures are shown in FIG. 69. FIGs. 67A-67C is a set of graphs depicting cytokine release as a measure of ex vivo human B cell activation. Levels of IFN-gamma (FIG. 67A), LI-6 (FIG. 67) and TNF-alpha (FIG. 67C) were measured. FIG. 68 is a graph depicting the amount of B cell activation as a result of various LNP formulations. LNP formulations including oleic acid demonstrated reduced splenic B cell activation. FIG. 69 shows phospholipid structures. FIG. 70 is a graph depicting Luc expression levels following administration of LUC mRNA encapsulated in various LNP formulations composed of novel PC and Oleic Acid Derivatives at 3, 6 and 24 hours following. FIGs. 71A-71B is a set of graphs depicting B cell interaction / association with various LNP formulations as assessed by a percentage of CD19+PE+ cells. Several LNP formulations are depicted in FIG. 71A. Oleic acid and Cmpd125 are depicted in FIG. 71B. FIG. 72 is a set of graphs depicting B cell activation with various LNP formulations as assessed by CD86 Expression Median Fluorescence Intensity. Several LNP formulations are depicted in FIG. 72A. Oleic acid and Cmpd125 are depicted in FIG. 72B. FIGs. 73A-73C are a set of graphs depicting Luc expression with various LNP formulations as assessed by a measurement of total flux at 3 hours (FIG. 73A), 6 hours (FIG. 73B), and 24 hours (FIG. 73C) following a dose. FIGs. 74A-74B are graphs depicting hEPO Expression (pg / mL) 6 hours following once weekly IV administration of hEPO mRNA-LNP formulations at weeks 1, 2, and 3. FIG. 75 is a graph depicting anti-PEG IgM production (ng / mL) 96 hours following administration of the second dose of LNP formulations. FIG. 76 is a graph depicting Luc expression of various LNP formulations. Luc expression was assessed by a measurement of total flux (p / s) at 3 hours following a dose, using whole body BLI imaging. FIG. 77 is a graph depicting B cell activation. Percentage of activated B cells (CD86+ CD69+) in splenic CD19+ cells for LNP formulations was measured. FIG. 78 is a graph depicting EPO expression. Concentration of EPO (ng / mL) was measured at prebleed, 6 hours, and 24 hours, each of the 6 weeks. FIG. 79 is a graph depicting hEPO expression (ng / mL) at predose, 2 hours, 6 hours, 12 hours, 24 hours, 48 hours, and 72 hours following once weekly IV administration of hEPO mRNA-LNP formulations. FIG. 80 is a graph depicting levels of anti-PEG IgM (U / mL) following once weekly IV administration of the hEPO mRNA-LNP formulations. FIG. 81 is a graph depicting levels of anti-PEG IgG (U / mL) following once weekly IV administration of the hEPO mRNA - LNP formulations. FIG. 82 is a graph depicting B cell activation. Percentage of activated B cells (CD86+ CD27+) in CD19+ cells for LNP formulations was measured. FIG. 83 is a graph depicting monocyte activation measured for LNP formulations. FIGs. 84A-84B are graphs depicting EPO expression. Concentration of EPO (ng / mL) was measured at 2 hours, 6 hours, 12 hours, 24 hours, and 48 hours following the first injection and the fifth injection. FIGs. 85A-85E are graphs depicting EPO expression. Concentration of EPO (ng / mL) was measured on day I and day 29 at 2 hours, 6 hours, 12 hours, 24 hours, and 48 hours for each co-medication group. FIGs. 86A-86C are graphs depicting immune cell populations. Shows the percentage of B cells (FIG. 86A), B1a cells (FIG. 86B), and monocytes (FIG. 86C) in PBMCs for each co-medication group at day -7, 24 hours post first injection, and 24 hours post fifth injection. FIG. 87 is a graph depicting B cell activation. The percentage of activated B cells in circulating B cells was measured for each co-medication group at day -7, 24 hours post first injection, and 24 hours post fifth injection. FIG. 88 is a graph depicting monocyte activation. The percentage of activated monocytes / macrophages in circulating PBMCs was measured for each co-medication group at day -7, 24 hours post first injection, and 24 hours post fifth injection. FIGs. 89A-89B are graphs depicting anti-PEG response. Anti-PEG IgM levels (U / mL) (FIG. 89A) and anti-PEG IgG levels (U / mL) (FIG. 89B) were measured for each co-medication group at baseline, day 9 post first injection, and day 34 post fifth injection. FIGs. 90A-90B are two graphs showing anti-PEG IgM levels (U / mL) and EPO levels (ng / mL) in two of the groups from FIG. 78: C57BI6J (FIG. 90A) and sIgM- / - (FIG. 90B). In FIG. 90A, anti-PEG IgM levels are graphed as light grey circles; in FIG. 90B. they arc represented by black circles. EPO concentrations are indicated by black circles (FIG. 90A) and black squares (FIG. 90B). FIGs. 91A-91B: The effect of co-medication on ABC in NHP. Co-medication alleviates cytokine (IL-6) production in NHPs (FIG. 91A) and co-medication with Gilcnya reduces anti-PEG IgM production, consistent with reduced ABC (FIG. 91B). FIG. 92: B cells proliferate in the presence of DSPC LNPs. Splenic cells were stained with CFSE and after washing, incubated with IL-6, anti-BCR, DOPC liposomes, DSPC LNPs containing mRNA, DSPC LNPs containing siRNA or empty LNPs for 4 days at 37°C. On day 4, the cells were harvested, washed and stained for surface markers, (CD19 and CD3) before they were measured on a BDFortessa flow cytometer and analyzed with ModFit 4.1 software. FIG. 93: DSPC LNPs induce calcium release in B cells. Splenic cells were stained with Calcium Sensor Dye eFluor ®< 514, CD19, and CD3. After washing, a calcium baseline was acquired for 30 seconds on a BDFortessa flow cytometer. Immediately after, the cells were incubated with DSPC LNPs containing mRNA, DOPC liposomes, oleic LNPs, or anti BCR and the calcium signal was acquired for 360 seconds. Then, the cell stimulation cocktail was added to the cells and the signal was acquired for an additional 30 seconds. The analysis was performed using ModFit 4.1 software. DETAILED DESCRIPTION

[0067] This disclosure provides lipid-comprising compounds and compositions that are not subject to ABC and / or that have reduced toxicity, as well as methods for delivering LNPs to a subject without promoting LNP-related drug responses, including ABC and LNP-induced toxicity (e.g., coagulopathy, disseminated intravascular coagulation, vascular thrombosis, CARPA, APR, or a combination thereof).

[0068] Lipid-comprising compounds and compositions are compounds and compositions that comprise or are conjugated to one or more lipids. These agents may be referred to herein as lipid-conjugated agents or lipidated agents. Alternatively such lipids may encapsulate agents such as prophylactic, therapeutic and diagnostic agents. These agents may be referred to herein as lipid-encapsulated agents or lipid nanoparticle (LNP) encapsulated agents.

[0069] Thus, it is to be understood that this disclosure provides improved compounds and compositions for reducing or eliminating ABC and toxicity upon in vivo administration. For brevity, this disclosure may however in some instances refer to compositions or formulations such as lipid nanoparticles or LNPs. This is intended for exemplary purposes and it is to be understood that the various teachings provided herein apply equally to individual compounds. such as lipid-conjugated compounds, unless explicitly stated otherwise.Accelerated Blood Clearance

[0070] The invention provides compounds, compositions and methods of use thereof for reducing the effect of ABC on a repeatedly administered active agent such as a biologically active agent. As will be readily apparent, reducing or eliminating altogether the effect of ABC on an administered active agent effectively increases its half-life and thus its efficacy.

[0071] In some embodiments the term reducing ABC refers to any reduction in ABC in comparison to a positive reference control ABC inducing LNP such as an MC3 LNP. ABC inducing LNPs cause a reduction in circulating levels of an active agent upon a second or subsequent administration within a given time frame. Thus a reduction in ABC refers to less clearance of circulating agent upon a second or subsequent dose of agent, relative to a standard LNP. The reduction may be, for instance, at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, or 100%. In some embodiments the reduction is 10-100%, 10-50%, 20-100%, 20-50%, 30-100%, 30-50%, 40%-100%, 40-80%, 50-90%, or 50-100%. Alternatively the reduction in ABC may be characterized as at least a detectable level of circulating agent following a second or subsequent administration or at least a 2 fold, 3 fold, 4 fold, 5 fold increase in circulating agent relative to circulating agent following administration of a standard LNP. In some embodiments the reduction is a 2-100 fold, 2-50 fold, 3-100 fold, 3-50 fold, 3-20 fold, 4-100 fold, 4-50 fold, 4-40 fold, 4-30 fold, 4-25 fold, 4-20 fold, 4-15 fold, 4-10 fold, 4-5 fold, 5 - 100 fold, 5-50 fold, 5-40 fold, 5-30 fold, 5-25 fold, 5-20 fold, 5-15 fold, 5-10 fold, 6-100 fold, 6-50 fold. 6-40 fold, 6-30 fold, 6-25 fold, 6-20 fold, 6-15 fold, 6-10 fold, 8-100 fold. 8-50 fold, 8-40 fold, 8-30 fold, 8-25 fold, 8-20 fold, 8-15 fold, 8-10 fold, 10-100 fold, 10-50 fold, 10-40 fold, 10-30 fold, 10-25 fold. 10-20 fold. 10-15 fold, 20-100 fold, 20-50 fold. 20-40 fold, 20-30 fold, or 20-25 fold.

[0072] The disclosure provides lipid-comprising compounds and compositions that are less susceptible to clearance and thus have a longer half-life in vivo. This is particularly the case where the compositions are intended for repeated including chronic administration, and even more particularly where such repeated administration occurs within days or weeks.

[0073] Significantly, these compositions are less susceptible or altogether circumvent the observed phenomenon of accelerated blood clearance (ABC). ABC is a phenomenon in which certain exogenously administered agents are rapidly cleared from the blood upon second and subsequent administrations. This phenomenon has been observed, in part, for a variety of lipid-containing compositions including but not limited to lipidated agents, liposomes or other lipid-based delivery vehicles, and lipid-encapsulated agents. Heretofore, the basis of ABC has been poorly understood and in some cases attributed to a humoral immune response and accordingly strategies for limiting its impact in vivo particularly in a clinical setting have remained elusive.

[0074] This disclosure provides compounds and compositions that arc less susceptible, if at all susceptible, to ABC. In some important aspects, such compounds and compositions are lipid-comprising compounds or compositions. The lipid-containing compounds or compositions of this disclosure, surprisingly, do not experience ABC upon second and subsequent administration in vivo. This resistance to ABC renders these compounds and compositions particularly suitable for repeated use in vivo, including for repeated use within short periods of time, including days or 1-2 weeks. This enhanced stability and / or half-life is due, in part, to the inability of these compositions to activate B1a and / or B1b cells and / or conventional B cells, pDCs and / or platelets.

[0075] This disclosure therefore provides an elucidation of the mechanism underlying accelerated blood clearance (ABC). It has been found, in accordance with this disclosure and the inventions provided herein, that the ABC phenomenon at least as it relates to lipids and lipid nanoparticles is mediated, at least in part an innate immune response involving B1a and / or B1b cells. pDC and / or platelets. B1a cells are normally responsible for. secreting natural antibody, in the form of circulating IgM. This IgM is poly-reactive, meaning that it is able to bind to a variety of antigens, albeit with a relatively low affinity for each.

[0076] It has been found in accordance with the invention that some lipidated agents or lipid-comprising formulations such as lipid nanoparticles administered in vivo trigger and are subject to ABC. It has now been found in accordance with the invention that upon administration of a first dose of the LNP. one or more cells involved in generating an innate immune response (referred to herein as sensors) bind such agent, are activated, and then initiate a cascade of immune factors (referred to herein as effectors) that promote ABC and toxicity. For instance, B1a and B1b cells may bind to LNP, become activated (alone or in the presence of other sensors such as pDC and / or effectors such as IL6) and secrete natural IgM that binds to the LNP. Pre-existing natural IgM in the subject may also recognize and bind to the LNP, thereby triggering complement fixation. After administration of the first dose, the production of natural IgM begins within 1-2 hours of administration of the LNP. Typically by about 2-3 weeks the natural IgM is cleared from the system due to the natural half-life of IgM. Natural IgG is produced beginning around 96 hours after administration of the LNP. The agent, when administered in a naive setting, can exert its biological effects relatively unencumbered by the natural IgM produced post-activation of the B1a cells or B1b cells or natural IgG. The natural IgM and natural IgG are non-specific and thus are distinct from anti-PEG IgM and anti-PEG IgG.

[0077] Although Applicant is not bound by mechanism, it is proposed that LNPs trigger ABC and / or toxicity through the following mechanisms. It is believed that when an LNP is administered to a subject the LNP is rapidly transported through the blood to the spleen. The LNPs may encounter immune cells in the blood and / or the spleen. A rapid innate immune response is triggered in response to the presence of the LNP within the blood and / or spleen. Applicant has shown herein that within hours of administration of an LNP several immune sensors have reacted to the presence of the LNP. These sensors include but are not limited to immune cells involved in generating an immune response, such as B cells, pDC, and platelets. The sensors may be present in the spleen, such as in the marginal zone of the spleen and / or in the blood. The LNP may physically interact with one or more sensors, which may interact with other sensors. In such a case the LNP is directly or indirectly interacting with the sensors. The sensors may interact directly with one another in response to recognition of the LNP. For instance many sensors are located in the spleen and can easily interact with one another. Alternatively one or more of the sensors may interact with LNP in the blood and become activated. The activated sensor may then interact directly with other sensors or indirectly (e.g., through the stimulation or production of a messenger such as a cytokine e.g., II.6)

[0078] In some embodiments the LNP may interact directly with and activate each of the following sensors: pDC, B1a cells. B1b cells, and platelets. These cells may then interact directly or indirectly with one another to initiate the production of effectors which ultimately lead to the ABC and / or toxicity associated with repeated doses of LNP. For instance, Applicant has shown that LNP administration leads to pDC activation, platelet aggregation and activation and B cell activation. In response to LNP platelets also aggregate and are activated and aggregate with B cells. pDC cells are activated. LNP has been found to interact with the surface of platelets and B cells relatively quickly. Blocking the activation of any one or combination of these sensors in response to LNP is useful for dampening the immune response that would ordinarily occur. This dampening of the immune response results in the avoidance of ABC and / or toxicity.

[0079] The sensors once activated produce effectors. An effector, as used herein, is an immune molecule produced by an immune cell, such as a B cell. Effectors include but are not limited to immunoglobulin such as natural IgM and natural lgG and cytokines such as IL6. B1a and B1b cells stimulate the production of natural IgMs within 2-6 hours following administration of an LNP. Natural 1gG can be detected within 96 hours. IL6 levels arc increased within several hours. The natural IgM and IgG circulate in the body for several days to several weeks. During this time the circulating effectors can interact with newly administered LNPs, triggering those LNPs for clearance by the body. For instance, an effector may recognize and bind to an LNP. The Fc region of the effector may be recognized by and trigger uptake of the decorated LNP by macrophage. The macrophage are then transported to the spleen. The production of effectors by immune sensors is a transient response that correlates with the timing observed for ABC.

[0080] If the administered dose is the second or subsequent administered dose, and if such second or subsequent dose is administered before the previously induced natural IgM and / or IgG is cleared from the system (e.g., before the 2-3 window time period), then such second or subsequent dose is targeted by the circulating natural IgM and / or natural IgG or Fc which trigger alternative complement pathway activation and is itself rapidly cleared. When LNP are administered after the effectors have cleared from the body or are reduced in number, ABC is not observed.

[0081] Thus, it is useful according to aspects of the invention to inhibit the interaction between LNP and one or more sensors, to inhibit the activation of one or more sensors by LNP (direct or indirect), to inhibit the production of one or more effectors, and / or to inhibit the activity of one or more effectors. In some embodiments the LNP is designed to limit or block interaction of the LNP with a sensor. For instance the LNP may have an altered PC and / or PEG to prevent interactions with sensors. Alternatively or additionally an agent that inhibits immune responses induced by LNPs may be used to achieve any one or more of these effects.

[0082] It has also been determined that conventional B cells are also implicated in ABC. Specifically, upon first administration of an agent, conventional B cells, referred to herein as CD19(+), bind to and react against the agent. Unlike B1a and B1b cells though, conventional B cells are able to mount first an IgM response (beginning around 96 hours after administration of the LNPs) followed by an IgG response (beginning around 14 days after administration of the LNPs) concomitant with a memory response. Thus conventional Bcells react against the administered agent and contribute to IgM (and eventually IgG) that mediates ABC. The IgM and IgG are typically anti-PEG IgM and anti-PEG IgG.

[0083] It is contemplated that in some instances, the majority of the ABC response is mediated through B1a cells and B1a-mediated immune responses. It is further contemplated that in some instances, the ABC response is mediated by both IgM and IgG, with both conventional B cells and B1a cells mediating such effects. In yet still other instances, the ABC response is mediated by natural IgM molecules, some of which are capable of binding to natural 1gM, which may be produced by activated B1a cells. The natural IgMs may bind to one or more components of the LNPs, e.g., binding to a phospholipid component of the LNPs (such as binding to the PC moiety of the phospholipid) and / or binding to a PEG-lipid component of the LNPs (such as binding to PEG-DMG, in particular, binding to the PEG moiety of PEG-DMG). Since B1a expresses CD36, to which phosphatidylcholine is a ligand, it is contenplated that the CD36 receptor may mediate the activation of B1a cells and thus production of natural IgM. In yet still other instances, the ABC response is mediated primarily by conventional B cells.

[0084] It has been found in accordance with the invention that the ABC phenomenon can be reduced or abrogated, at least in part, through the use of compounds and compositions (such as agents, delivery vehicles, and formulations) that do not activate B1a cells. Compounds and compositions that do not activate B1a cells may be referred to herein as B1a inert compounds and compositions. It has been further found in accordance with the invention that the ABC phenomenon can be reduced or abrogated, at least in part, through the use of compounds and compositions that do not activate conventional B cells. Compounds and compositions that do not activate conventional B cells may in some embodiments be referred to herein as CD19-inert compounds and compositions. Thus, in some embodiments provided herein, the compounds and compositions do not activate B1a cells and they do not activate conventional B cells. Compounds and compositions that do not activate B1a cells and conventional B cells may in some embodiments be referred to herein as B 1a / CD19-inert compounds and compositions.

[0085] These underlying mechanisms were not heretofore understood, and the role of B1a and B1b cells and their interplay with conventional B cells in this phenomenon was also not appreciated.

[0086] Accordingly, this disclosure provides compounds and compositions that do not promote ABC. These may be further characterized as not capable of activating B1a and / or B1b cells, platelets and / or pDC, and optionally conventional B cells also. These compounds (e.g., agents, including biologically active agents such as prophylactic agents, therapeutic agents and diagnostic agents, delivery vehicles, including liposomes, lipid nanoparticles. and other lipid-based encapsulating structures, etc.) and compositions (e.g., formulations, etc.) arc particularly desirable for applications requiring repeated administration, and in particular repeated administrations that occur within with short periods of time (e.g., within 1-2 weeks). This is the case, for example, if the agent is a nucleic acid based therapeutic that is provided to a subject at regular, closely-spaced intervals. The findings provided herein may be applied to these and other agents that are similarly administered and / or that are subject to ABC.

[0087] Of particular interest are lipid-comprising compounds, lipid-comprising particles, and lipid-comprising compositions as these are known to be susceptible to ABC. Such lipid-comprising compounds particles, and compositions have been used extensively as biologically active agents or as delivery vehicles for such agents. Thus, the ability to improve their efficacy of such agents, whether by reducing the effect of ABC on the agent itself or on its delivery vehicle, is beneficial for a wide variety of active agents.

[0088] Also provided herein are compositions that do not stimulate or boost an acute phase response (ARP) associated with repeat dose administration of one or more biologically active agents.

[0089] The composition, in some instances, may not bind to IgM, including but not limited to natural IgM.

[0090] The composition, in some instances, may not bind to an acute phase protein such as but not limited to C-reactive protein.

[0091] The composition, in some instances, may not trigger a CD5(+) mediated immune response. As used herein, a CD5(+) mediated immune response is an immune response that is mediated by B1a and / or B1b cells. Such a response may include an ABC response, an acute phase response, induction of natural IgM and / or IgG, and the like.

[0092] The composition, in some instances, may not trigger a CD19(+) mediated immune response. As used herein, a CD19(+) mediated immune response is an immune response that is mediated by conventional CD19(+), CD5(-) B cells. Such a response may include induction of IgM, induction of IgG, induction of memory B cells, an ABC response, an antidrug antibody (ADA) response including an anti-protein response where the protein may be encapsulated within an LNP, and the like.

[0093] B1a cells are a subset of B cells involved in innate immunity. These cells are the source of circulating IgM, referred to as natural antibody or natural serum antibody. Natural IgM antibodies are characterized as having weak affinity for a number of antigens, and therefore they are referred to as "poly-specific" or "poly-reactive", indicating their ability to bind to more than one antigen. B1a cells are not able to produce IgG. Additionally, they do not develop into memory cells and thus do not contribute to an adaptive immune response. However, they arc able to secrete IgM upon activation. The secreted IgM is typically cleared within about 2-3 weeks, at which point the immune system is rendered relatively naïve to the previously administered antigen. If the same antigen is presented after this time period (e.g., at about 3 weeks after the initial exposure), the antigen is not rapidly cleared. However. significantly, if the antigen is presented within that time period (e.g., within 2 weeks, including within 1 week, or within days), then the antigen is rapidly cleared. This delay between consecutive doses has rendered certain lipid-containing therapeutic or diagnostic agents unsuitable for use.

[0094] In humans, B1a cells are CD19(+), CD20(+), CD27(+), CD43(+), CD70(-) and CD5(+). In mice, B1a cells are CD19(+), CD5(+), and CD45 B cell isoform B220(+). It is the expression of CD5 which typically distinguishes B1a cells from other convention B cells. B1a cells may express high levels of CDS, and on this basis may be distinguished from other B-1 cells such as B-1b cells which express low or undetectable levels of CDS. CDS is a panT cell surface glycoprotein. B1a cells also express CD36, also known as fatty acid translocase. CD36 is a member of the class B scavenger receptor family. CD36 can bind many ligands, including oxidized low density lipoproteins, native lipoproteins, oxidized phospholipids, and long-chain fatty acids.

[0095] B1b cells are another subset of B cells involved in innate immunity. These cells arc another source of circulating natural IgM. Several antigens, including PS, are capable of inducing T cell independent immunity through B1b activation. CD27 is typically upregulated on B1b cells in response to antigen activation. Similar to B1a cells, the B1b cells are typically located in specific body locations such as the spleen and peritoneal cavity and are in very low abundance in the blood. The B1b secreted natural IgM is typically cleared within about 2-3 weeks, at which point the immune system is rendered relatively naïve to the previously administered antigen. If the same antigen is presented after this time period (e.g., at about 3 weeks after the initial exposure), the antigen is not rapidly cleared. However, significantly, if the antigen is presented within that time period (e.g., within 2 weeks, including within 1 week, or within days), then the antigen is rapidly cleared. This delay between consecutive doses has rendered certain lipid-containing therapeutic or diagnostic agents unsuitable for use.

[0096] In some embodiments it is desirable to block B1a and / or B1b cell activation. One strategy for blocking B1a and / or B1b cell activation involves determining which components of a lipid nanoparticle promote B cell activation and neutralizing those components. It has been discovered herein that at least PEG and phosphatidylcholine (PC) contribute to B1a and B1b cell interaction with other cells and / or activation. PEG may play a role in promoting aggregation between B1 cells and platelets, which may lead to activation. PC (a helper lipid in LNPs) is also involved in activating the B1 cells, likely through interaction with the CD36 receptor on the B cell surface. Numerous particles have PEG-lipid alternatives, PEG-less, and / or PC replacement lipids (e.g. oleic acid or analogs thereof) have been designed and tested. Applicant has established that replacement of one or more of these components within an LNP that otherwise would promote ABC upon repeat administration, is useful in preventing ABC by reducing the production of natural IgM and / or B cell activation. Thus, the invention encompasses LNPs that have reduced ABC as a result of a design which eliminates the inclusion of B cell triggers.

[0097] Another strategy for blocking B1a and / or B1b cell activation involves using an agent that inhibits immune responses induced by LNPs. These types of agents are discussed in more detail below. In some embodiments these agents block the interaction between B1a / B1b cells and the LNP or platelets or pDC. For instance the agent may be an antibody or other binding agent that physically blocks the interaction. An example of this is an antibody that binds to CD36 or CD6. The agent may also be a compound that prevents or disables the B1a / B1b cell from signaling once activated or prior to activation. For instance, it is possible to block one or more components in the B1a / B1b signaling cascade the results from B cell interaction with LNP or other immune cells. In other embodiments the agent may act one or more effectors produced by the B1a / B1b cells following activation. These effectors include for instance, natural IgM and cytokines.

[0098] It has been demonstrated according to aspects of the invention that when activation of pDC cells is blocked, B cell activation in response to LNP is decreased. Thus, in order to avoid ABC and / or toxicity, it may be desirable to prevent pDC activation. Similar to the strategies discussed above, pDC cell activation may be blocked by agents that interfere with the interaction between pDC and LNP and / or B cells / platelets. Alternatively agents that act on the pDC to block its ability to get activated or on its effectors can be used together with the LNP to avoid ABC.

[0099] Platelets also play an important role in ABC and toxicity. Very quickly after a first dose of LNP is administered to a subject platelets associate with the LNP, aggregate and are activated. In some embodiments it is desirable to block platelet aggregation and / or activation. One strategy for blocking platelet aggregation and / or activation involves determining which components of a lipid nanoparticle promote platelet aggregation and / or activation and neutralizing those components. It has been discovered herein that at least PEG contribute to platelet aggregation, activation and / or interaction with other cells. Numerous particles have PEG-lipid alternatives and PEG-less have been designed and tested. Applicant has established that replacement of one or more of these components within an LNP that otherwise would promote ABC upon repeat administration, is useful in preventing ABC by reducing the production of natural IgM and / or platelet aggregation. Thus, the invention encompasses LNPs that have reduced ABC as a result of a design which eliminates the inclusion of platelet triggers. Alternatively agents that act on the platelets to block its activity once it is activated or on its effectors can be used together with the LNP to avoid ABC.Measuring ABC Activity and related activities

[0100] Various compounds and compositions provided herein, including LNPs, do not promote ABC activity upon administration in vivo. These LNPs may be characterized and / or identified through any of a number of assays, such as but not limited to those described below, as well as any of the assays disclosed in the Examples section, include the methods subsection of the Examples

[0101] In some embodiments the methods involve administering an LNP without producing an immune response that promotes ABC. An immune response that promotes ABC involves activation of one or more sensors, such as B1 cells, pDC, or platelets, and one or more effectors, such as natural IgM, natural IgG or cytokines such as IL6. Thus administration of an LNP without producing an immune response that promotes ABC, at a minimum involves administration of an LNP without significant activation of one or more sensors and significant production of one or more effectors. Significant used in this context refers to an amount that would lead to the physiological consequence of accelerated blood clearance of all or part of a second dose with respect to the level of blood clearance expected for a second dose of an ABC triggering LNP. For instance, the immune response should be dampened such that the ABC observed after the second dose is lower than would have been expected for an ABC triggering LNP.B1a or B1b activation assay

[0102] Certain compositions provided in this disclosure do not activate B cells, such as B1a or B1b cells (CDI9+ CD5+) and / or conventional B cells (CD19+ CD5-). Activation of B1a cells, B1b cells, or conventional Bcells may be determined in a number of ways, some of which are provided below. B cell population may be provided as fractionated B cell populations or unfractionated populations of splenocytes or peripheral blood mononuclear cells (PBMC). If the latter, the cell population may be incubated with the LNP of choice for a period of time, and then harvested for further analysis. Alternatively, the supernatant may be harvested and analyzed.Upregulation of activation marker cell surface expression

[0103] Activation of B1a cells, B1b cells, or conventional B cells may be demonstrated as increased expression of B cell activation markers including late activation markers such as CD86. In an exemplary non-limiting assay, unfractionatcd B cells are provided as a splenocyte population or as a PBMC population, incubated with an LNP of choice for a particular period of time, and then stained for a standard B cell marker such as CD19 and for an activation marker such as CD86, and analyzed using for example flow cytometry. A suitable negative control involves incubating the same population with medium, and then performing the same staining and visualization steps. An increase in CD86 expression in the test population compared to the negative control indicates R cell activationPro-inflammatory cytokine release

[0104] B cell activation may also be assessed by cytokine release assay. For example, activation may be assessed through the production and / or secretion of cytokines such as IL-6 and / or TNF-alpha upon exposure with LNPs of interest.

[0105] Such assays may be performed using routine cytokine secretion assays well known in the art. An increase in cytokine secretion is indicative of B cell activation.LNP binding / association to and / or uptake by B cells

[0106] LNP association or binding to B cells may also be used to assess an LNP of interest and to further characterize such LNP. Association / binding and / or uptake / internalization may be assessed using a detectably labeled, such as fluorescently labeled, LNP and tracking the location of such LNP in or on B cells following various periods of incubation.

[0107] The invention further contemplates that the compositions provided herein may be capable of evading recognition or detection and optionally binding by downstream mediators of ABC such as circulating IgM and / or acute phase response mediators such as acute phase proteins (e.g., C-reactive protein (CRP).Methods of use for reducing ABC

[0108] Also provided herein are methods for delivering LNPs, which may encapsulate an agent such as a therapeutic agent, to a subject without promoting ABC.

[0109] In some embodiments, the method comprises administering any of the LNPs described herein, which do not promote ABC, for example, do not induce production of natural IgM binding to the LNPs, do not activate B1a and / or B1b cells. As used herein, an LNP that "does not promote ABC" refers to an LNP that induces no immune responses that would lead to substantial ABC or a substantially low level of immune responses that is not sufficient to lead to substantial ABC. An LNP that does not induce the production of natural IgMs binding to the LNP refers to LNPs that induce either no natural IgM binding to the LNPs or a substantially low level of the natural IgM molecules, which is insufficient to lead to substantial ABC. An LNP that does not activate B1a and / or B1b cells refer to LNPs that induce no response of B1a and / or B1b cells to produce natural IgM binding to the LNPs or a substantially low level of B1a and / or B1b responses, which is insufficient to lead to substantial ABC.

[0110] In some embodiments the terms do not activate and do not induce production are a relative reduction to a reference value or condition. In some embodiments the reference value or condition is the amount of activation or induction of production of a molecule such as IgM by a standard LNP such as an MC3 LNP. In some embodiments the relative reduction is a reduction of at least 30%, for example at least 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%. In other embodiments the terms do not activate cells such as B cells and do not induce production of a protein such as IgM may refer to an undetectable amount of the active cells or the specific protein.

[0111] In some instances, the LNPs described herein may be free of an epitope that activates B1a cells, for example, free of an epitope that activates or interacts with CD36 or CD6. Such LNPs contain either no epitopes capable of activating B1a cells or CD36 or contain such epitopes at a substantially low amount, which is not sufficient to activate B1a or CD36 to a level high enough for inducing substantial ABC. In other embodiments, the LNPs described herein may be free of an epitope that activates B1b cells. By substantially free of, it is meaclassical pnt that a LNP includes less than 99% of the recited agent. In some embodiments the LNP may include none of the recited agent. In some instances, the LNPs described herein may contain one or more helper lipid as described herein, which may comprise at least one fatty acid chain of at least 8C and at least one polar moiety. In some examples, the helper lipid does not activate B1a and / or B1b cells. In other examples, the helper lipid does not bind or has low binding affinity to CD36. Alternatively, the helper lipid may competitively inhibit phosphatidylcholine from binding to CD36.

[0112] Alternatively the LNP may be coadminstered (administered with, before or after) or coformulated with an agent that removes or targets B or B1a cells. An agent that removes or targets B or B1a cells may be Rituximab. Rituximab (RITUXAN ®< , GenentechBiogen) is a monoclonal antibody against the protein CD20, which is primarily found on the surface of immune system B cells. Rituximab interacts with CD20 on the surface of B cells and destroys B cells. As shown in the Examples, the combination of Rituximab and the LNP had significantly reduced ABC upon subsequent administration of LNP.

[0113] In other embodiments the agent may bind and / or inhibit CD6 on B1a cells. An exemplary agent that binds and / or inhibits CD6 on B1a cells is an anti-CD6 antibody, such as Alzumab. Alzumab (itolizumab, Biocon) is a humanized IgGI monoclonal antibody that selectively targets CD6, a pan T cell marker involved in co-stimulation, adhesion and maturation of T cells. Alzumab also binds to CD6 on the surface of B1a cells.

[0114] In some instances such methods may comprise (i) administering a first dose of an agent to a subject, (ii) administering a second or subsequent dose of the agent to the subject, wherein the second or subsequent dose is administered within 2 weeks of the first or prior dose, and (iii) repearing step (II) one or more times, wherein the agent is formulated with an LNP that does not promote ABC.

[0115] Another method for delivering an agent to a subject involves (i) administering a first dose of an agent to a subject, (ii) administering a second or subsequent dose of the agent to the subject, wherein the second or subsequent dose is administered within 2 weeks of the first or prior dose, and (iii) repeating step (ii) one or more times, wherein the half-life of the agent after the second and subsequent dose is at least 50%, 60%, 70%, 80%, 85%, 90%, 95% or more of the half-life of the agent after the first dose.

[0116] Still another method for delivering an agent to a subject involves (i) administering a first dose of an agent to a subject, (ii) administering a second or subsequent dose of the agent to the subject, wherein the second or subsequent dose is administered within 2 weeks of the first or prior dose. and (iii) repeating step (ii) one or more times, wherein the activity or blood concentration of the agent after the second and subsequent dose is at least 50%, 60%, 70%, 80%, 85%, 90%, 95% or more of the activity or blood concentration of the agent after the first dose.

[0117] Second or subsequent doses may be administered within 1 week, or within 6 days, or within 5 days, or within 4 days, or within 3 days, or within 2 days, or within 1 day of the first or prior dose.

[0118] The agent may be a biologically active agent such as a diagnostic agent or a therapeutic agent, although it is not so limited.

[0119] Agents may be administered two or more times, three or more times, four or more times, etc. Agent administration may therefore be repeated once, twice, 3, 4, 5, 6, 7, 8, 9, 10, or more times. The agent may be administered chronically or acutely, depending on its intended purpose.

[0120] The method may be a method of treating a subject having or at risk of having a condition that benefits from the biologically active agent, particularly if the biologically active agent is a therapeutic agent. Alternatively, the method may be a method of diagnosing a subject, in which case the biologically active agent is a diagnostic agent.

[0121] The second and subsequent doses of biologically active agent may maintain an activity of at least 50% of the activity of the first dose, or at least 60% of the first dose, or at least 70% of the first dose, or at least 75% of the first dose, or at least 80% of the first dose, or at least 85% of the first dose, or at least 90% of the first dose, or at least 95% of the first dose, or more, for at least 1 day, 2 days, 3 days, 4 days, 5 days, 6 days, or 7 days postadministration of the second or subsequent dose.

[0122] When the biologically active agent is an mRNA (a therapeutic mRNA or a mRNA encoding a vaccine antigen), a method for reducing ABC of LNPs encapsulating the mRNA can be performed using a low amount of the LNPs for the first dose, and / or the second dose (as well as the subsequent doses). The low doses can be equal to or less than 0.3 mg / kg, e.g., 0.2 mg / kg, or 0.1 mg / kg. In some instances, the first dose, the second dose, or both range from 0.1 to 0.3 mg / kg.

[0123] The interval between the first dose and the second dose in any of the methods described herein may be equal to or less than two weeks, for example, less than 21, 20, 19, 18, 17. 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 days. In some instances, the subject can be administered a dose once daily, every 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15. 16, 17, 18, 19, 20 or 21 days in any of the methods described herein.

[0124] Further, inhibiting ABC of LNPs in a subject can be achieved by the use of one or more secondary agents that inhibit immune responses induced by LNPs, e.g., inhibit the binding to or activity of sensors e.g., natural IgM production, natural IgG production, activation of B1a cells, activation of B1b cells, and / or activation of platelets and or dendritic cells or the activity or production of any effectors . The secondary agents are referred to alternatively as agents that inhibit immune responses induced by LNPs. In some instances, the secondary agent may inhibit the production of natural IgM that binds the LNPs, or neutralize such natural IgMs. In other instances, the secondary agent may inhibit activation of B1a cells or remove B1a cells. For example, such a secondary agent may inhibit a surface receptor of B1a cells, including, but not limited to CD36 . Alternatively or in addition, the secondary agent may interfere with the binding of IgM to its target. In other embodiments, the secondary agent may inhibit the production of natural IgG that binds the LNPs, or neutralize such natural IgGs or may interfere with the binding of IgG to its target. In other instances, the secondary agent may inhibit activation of B1b cells or remove B1b cells.Platelet effects and toxicity

[0125] The invention is further premised in part on the elucidation of the mechanism underlying dose-limiting toxicity associated with LNP administration. Such toxicity may involve coagulopathy, disseminated intravascular coagulation (DIC, also referred to as consumptive coagulopathy), whether acute or chronic, and / or vascular thrombosis. In some instances, the dose-limiting toxicity associated with LNPs is acute phase response (APR) or complement activation-related psudoallergy (CARPA).

[0126] As used herein, coagulopathy refers to increased coagulation (blood clotting) in vivo. The findings reported in this disclosure are consistent with such increased coagulation and significantly provide insight on the underlying mechanism. Coagulation is a process that involves a number of different factors and cell types, and heretofore the relationship between and interaction of LNPs and platelets has not been understood in this regard. This disclosure provides evidence of such interaction and also provides compounds and compositions that arc modified to have reduced platelet effect, including reduced platelet association, reduced platelet aggregation, and / or reduced platelet aggregation. The ability to modulate, including preferably down-modulate, such platelet effects can reduce the incidence and / or severity of coagulopathy post-LNP administration. This in turn will reduce toxicity relating to such LNP, thereby allowing higher doses of LNPs and importantly their cargo to be administered to patients in need thereof.

[0127] CARPA is a class of acute immune toxicity manifested in hypersensitivity reactions (HSRs), which may be triggered by nanomedicines and biologicals. Unlike allergic reactions, CARPA typically does not involve IgE but arises as a consequence of activation of the complement system, which is part of the innate immune system that enhances the body's abilities to clear pathogens. One or more of the following pathways, the classical complement pathway (CP), the alternative pathway (AP), and the lectin pathway (LP), may be involved in CARPA. Szebeni, Molecular Immunology, 61:163-173 (2014).

[0128] The classical pathway is triggered by activation of the C 1-complex, which contains. Clq, Clr, Cls, or Clqr2s2. Activation of the Cl -complex occurs when Clq binds to IgM or IgG complexed with antigens, or when Clq binds directly to the surface of the pathogen. Such binding leads to conformational changes in the Clq molecule, which leads to the activation of Clr, which in turn, cleave C1s. The Clr2s2 component now splits C4 and then C2, producing C4a, C4b, C2a, and C2b. C4b and C2b bind to form the classical pathway C3-convertase (C4b2b complex), which promotes cleavage of C3 into C3a and C3b. C3b then binds the C3 convertase to from the C5 convertase (C4b2b3b complex). The alternative pathway is continuously activated as a result of spontaneous C3 hydrolysis. Factor P (properdin) is a positive regulator of the alternative pathway. Oligomerization of properdin stabilizes the C3 convertase, which can then cleave much more C3. The C3 molecules can bind to surfaces and recruit more B, D, and P activity, leading to amplification of the complement activation.

[0129] Acute phase response (APR) is a complex systemic innate immune responses for preventing infection and clearing potential pathogens. Numerous proteins arc involved in APR and C-reactive protein is a well-characterized one.

[0130] It has been found, in accordance with the invention, that certain LNP are able to associate physically with platelets almost immediately after administration in vivo, while other LNP do not associate with platelets at all or only at background levels. Significantly, those LNPs that associate with platelets also apparently stabilize the platelet aggregates that are formed thereafter. Physical contact of the platelets with certain LNPs correlates with the ability of such platelets to remain aggregated or to form aggregates continuously for an extended period of time after administration. Such aggregates comprise activated platelets and also innate immune cells such as macrophages and B cells.

[0131] Platelet aggregation is observed soon after LNP administration, and appears to occur at the same time as or potentially before platelet activation as evidenced through increased expression of platelet activation markers such as CD3I and CD62P. LNPs that do not associate with significant numbers of platelets but which are able to activate platelets to a lesser degree than the more robust LNPs (discussed above) also cause platelet aggregation very early after administration, and presumably prior to platelet activation. Thus, in vivo, LNP association with platelets appears to occur at about the same time as aggregation of platelets, and presumably prior to the peak of platelet activation.

[0132] Also significant is the additional observation that a subset of LNPs are able to activate platelets, even without appreciable physical association with platelets. This subset is also able to form platelet aggregates comprising R cells and macrophages

[0133] Certain LNPs have also been shown to stimulate early interaction between platelets (whether or not activated) and macrophages and B cells, thereby activating these latter cells as well. The effect of LNPs on B cells and macrophages is therefore both direct and indirect, but ultimately can lead to increased activation of such cells.

[0134] Activation of platelets could mediate complement activation. It is therefore contemplated that certain LNPs may induce dose-limiting toxicity such as CARPA and APR via activation of platelets and subsequently the complement system. Certain lipid components of LNPs, such as phosphatidylcholine may bind to and activate CD36 on platelets, which would trigger the TLR2 / 4 / 6 signaling, leading to aggregation and activation of the platelets. Activated platelets express CD62P (P selectin), which is a C3b-binding protein and can trigger the complement cascade. Activated platelets also recruit immune cells such as macrophages and neutrophils, which lead to further immune responses including cytokine (e.g., IL-6) secretion. Further, properdin was found to bind directly to activated platelet via, e.g., CD62P and recruits C3b or C3(H 2 O), thus triggering the alternative pathway. Saggu et al., J. Immunol. 190:6457-6467 (2013).

[0135] Accordingly, uses of LNPs that do not induce platelet activation and / or aggregation; and / or do not promote the activation of the complement system (e.g., the classic pathway and / or the alternative pathway) could reduce the risk of LNP-related toxicity. Such LNPs may not induce the activation of platelets and / or the complement system at all. Alternatively, such LNPs may induce a substantially low level of platelet activation and / or complement system activation, which is not sufficient to result in substantial dose-limiting toxicity.

[0136] Alternatively or in addition, secondary agents that block the initial platelet activation / aggregation, the initial activation of the complement system, and / or the downstream complement cascade, either in the classic pathway or in the alternative pathway, could be used to prevent or reduce LNP-related toxicity. In some instances, such a secondary agent may inhibit platelet activation, for example, inhibit CD36 activation triggered by LNPs. In other instances, the secondary agent may inhibit CARPA or ARP, for example, inhibit the classical pathway and / or the alternative pathway. Such a secondary agent may target at least one component in the complement system or proteins involved in ARP, thereby blocking the reaction cascade. For example, the secondary agent may be an antagonist of a TLR receptor (TLR2. TLR4, or TLR6), CD62P, CD31, properdin, a component of the complement system (e.g., Clq, C3a, C3b, C5a, and C5b). In yet other instances, the secondary agent may be an agent that can alleviate at least one symptom of LNP-related toxicity. Such agents include, but are not limited to, nonsteroidal anti-inflammatory drug (NSAID) or an antihistamine agent, which can be a histamine receptor blocker such as an H1 antagonist or an H1 inverse agonist.

[0137] In some embodiments, dose-limiting toxicity and / or ABC can be reduced in a subject being treated with a therapeutic regimen involving LNP-mcdiated drug delivery by using LNPs that do not activate a thrombospondin receptor (e.g., CD36), which may be expressed on the surface of immune cells (e.g., B1a or B1b cells); or other surface receptors involved in triggering the immune responses that lead to dose-limiting toxicity and / or ABC. Such LNPs may not activate the thrombospondin receptor at all, or could only induce a substantially low level of its activity such that it is insufficient to induce clinically significant dose-limiting toxicity and / or ABC. Alternatively or in addition, dose-limiting toxicity and / or ABC can be reduced in a subject being treated with a therapeutic regimen involving LNP-mediatcd drug delivery by using one or more secondary agent that inhibits the activity of a thrombospondin receptor (e.g., CD36) expressed on the surface of immune cells and platelets. The thrombospondins (TSP) are a family of multifunctional proteins that are expressed on the surface of or secreted by cells such as blood platelets. The family consists of thrombospondins 1-5. TSP-1 is a inhibitory ligand of CD36.

[0138] Based on these findings, this disclosure contemplates and provides LNPs as well as LNP-formulatcd active agents that have reduced platelet association and / or reduced platelet activation and / or reduced platelet aggregation activity. Use of such LNPs, for example as a delivery vehicle for an active agent, reduces the risk of developing coagulopathy, such as disseminated intravascular coagulation (DIC, also referred to as consumptive coagulopathy), whether acute or chronic, and / or vascular thrombosis, as well as any toxicity related thereto. If such toxicity is dose-limiting, then use of these LNPs will enable administration of higher LNP doses and more importantly will enable the delivery of higher doses of the active agent cargo carried by such LNP.

[0139] The diminution of the platelet response after LNP administration has additional desirable effects, some of which may be synergistic. LNPs have been reported to activate complement shortly after administration. This activation may be direct or indirect. For example, it has been reported that activated platelets are able to activate complement. Thus LNPs that reduce or prevent platelet activation will also indirectly reduce or prevent complement activation. Complement activation can also contribute to coagulation, for example through complement-mediated generation of thrombin. Thrombin converts available fibrinogen to fibrin, which in turn forms clots together with platelets. Activated platelets have thrombin receptors on their surface and therefore are able to recruit and / or raise the local concentration of thrombin, thereby enhancing fibrin production and ultimately clot formation. The disclosure therefore contemplates and provides additional LNPs that do not activate complement or do not activate complement to the same degree as existing LNPs. Yet still additional LNPs provided herewith are those that do not activate platelet and do not activate complement.

[0140] Similarly, this disclosure contemplates LNPs that interfere with properdin binding to platelets. Properdin is a positive regulator of the alternative pathway of the complement system. It has been shown to bind to activated platelets, thereby activating the alternative pathway in response to and in the vicinity of the activated platelet. Thus further contemplated is the use of a properdin inhibitors in combination with LNPs provided herein whether such LNPs activate or do not activate platelets, as defined below. Properdin inhibitors include DNA and sulfated glucoconjugates, both of which are bound by properdin and may interfere with properdin binding to activated platelets.

[0141] This disclosure therefore contemplates and provides, in some aspects, LNPs and LNP formulations that have reduced platelet effects including reduced platelet association and / or reduced platelet activation and / or reduced platelet aggregation activity. Certain LNPs may affect one, two or all three of these platelet activities. For example, some LNP may have reduced platelet association activity, or reduced platelet aggregation activity, or reduced platelet activation activity. Some LNP may have reduced platelet association activity and or reduced platelet activation activity, or reduced platelet association activity and reduced platelet activation activity, or reduced platelet aggregation activity and reduced platelet activation activity. Some LNP may have reduced platelet association activity, reduced platelet aggregation activity, and reduced platelet activation activity.

[0142] The disclosure contemplates that some LNPs may be universal LNPs, intending that they will down-modulate (or not stimulate in the first instance) one or more of the afore-mentioned platelet activities upon administration in the majority of patients or in all patients.

[0143] Additionally, the disclosure contemplates that some LNPs may in some instances be defined and thus identified as patient-specific. That is, some LNPs may be effective at downregulating a platelet response, as described herein, in some but not all patients. Thus, in some instances, some LNPs and LNP formulations may be identified for particular patients and may then be used only for those particular patients.

[0144] In some instances, the findings provided herein may be applied directly to biologically active agents. For example, the biologically active agent that is a lipid or is conjugated to a lipid or that is conjugated to a PEG moiety directly or indirectly, may be modified as described herein to render the agent unable to stimulate a platelet response or cascade.Platelet activity assays

[0145] These various activities may be measured as described herein and / or as performed in the art. For example, platelet activation may be assessed by increased expression of activation markers such as CD31 and CD62P. Platelet aggregation may be assessed by flow cytometry. Similarly flow cytometry may be used to detect non-platelet types such as B cells and macrophages within such aggregates. It is to be understood that the platelet effects of LNP can be assessed in vivo. for example in an animal model, as well as in vitro using for example human blood. These assays may be used to screen for and / or identify LNP having one or more of the afore-mentioned activities.Compounds and Compositions, including LNP

[0146] The disclosure provides lipid-comprising compositions that are less susceptible to clearance and thus have a longer half-life in vivo. This is particularly important where the compositions are intended for repeated including chronic administration, and even more particularly where such repeated administration occurs within days or weeks.

[0147] Significantly, these compositions are less susceptible or altogether circumvent the observed phenomenon of accelerated blood clearance (ABC). ABC is a phenomenon in which lipid-containing exogenously administered agents are rapidly cleared from the blood upon second and subsequent administrations. This phenomenon has been observed for a variety of lipid-containing compositions, including, but not limited to, liposomes, lipid nanoparticles, and lipid-encapsulated agents. Heretofore, the basis of ABC has been poorly understood and accordingly strategies for avoiding it have remained elusive.

[0148] The lipid-containing compositions of this disclosure, surprisingly, do not experience or are minimally affected by ABC upon second and subsequent administration in vivo. This resistance to ABC renders these compositions particularly suitable for repeated use in vivo, including for repeated use within short periods of time, including days or 1-2 weeks.

[0149] This resistance to ABC is due in part to the inability of these compositions to activate B1a cells. Such compositions are therefore referred to herein as B1a inert compositions or compositions that do not activate substantial B1a. intending that these compositions, when combined with B1a cells, do not activate B1a cells. Activation of B1a cells may be determined in a number of ways including, but not limited to, increased expression of activation markers such as CD86, and expression and / or secretion of cytokines. These compositions may or may not bind to B1a cells, and they may or may not bind to circulating IgM. Thus, these compositions may evade detection by circulating IgM and / or by B1a cells.

[0150] B1a cells are a subset of B cells involved in innate immunity. These cells are the source of circulating IgM, referred to as natural antibody or natural serum antibody. These IgM antibodies are characterized as having weak affinity for a number of antigens, and therefore they are referred to as "poly-specific" or "poly-reactive", describing their ability to bind to more than one antigen. Although able to produce such IgM, B1a cells are not capable of producing IgG. Additionally, they do not develop into memory cells and thus do not contribute to an adaptive immune response. However, they are able to secrete IgM upon activation. The secreted IgM is typically cleared within about 12 days (half-life of IgM in sera is about 5-8 days, Nature Review Drug Discovery 2, 52-62. January 2003), at which point the immune system is rendered relatively naïve to the previously administered antigen. If the same antigen is presented after this time period (e.g., at about 2 weeks after the initial exposure), the antigen is not rapidly cleared. However, significantly, if the antigen is presented within that time period (e.g., within 2 weeks, including within 1 week, or within days), then the antigen is rapidly cleared. This delay between consecutive doses has rendered certain lipid-containing therapeutic or diagnostic compositions unsuitable for repeated use.

[0151] The compounds, particles, and compositions described herein overcome these limitations, thereby transforming a variety of lipid-containing compositions into efficacious therapeutic and diagnostic agents. The B1a lipid-compositions provided herein do not undergo accelerated blood clearance upon repeat administration and thus can be administered repeatedly to a subject, including within short periods of time, without loss of activity.

[0152] Resistance to ABC may also be due in part to the inability of these compositions to activate B1b cells, pDC and / or platelets. Such compositions are therefore referred to herein as B1b pDC and / or platelets inert compositions or compositions that do not activate substantial B1b pDC and / or platelets, intending that these compositions, when combined with B1b cells pDC and / or platelets, do not activate B1b cells pDC and / or platelets, respectively. Activation of B 1b cells, pDC and / or platelets may be determined in a number of ways including, but not limited to, increased expression of activation markers such as CD11b (for B1b cells), and expression and / or secretion of cytokines, and ability to activate B cells (pDC). These compositions may or may not bind to B1b cells, pDC and / or platelets, and they may or may not bind to circulating IgM or IgG. Thus, these compositions may evade detection by circulating IgM, IgG and / or by B1a cells pDC and / or platelets.

[0153] Particles, such as LNP, typically comprise one or more of the following components: lipids (which may include cationic lipids, helper lipids which may be neutral lipids, zwitterionic lipid, anionic lipids, and the like), structural lipids such as cholesterol or cholesterol analogs, fatty acids, polymers, stabilizers, salts, buffers, solvent, and the like.

[0154] Certain of the LNPs provided herein comprise a cationic lipid, a helper lipid, a structural lipid, and a stabilizer which may or may not be provided conjugated to another lipid.

[0155] The cationic lipid may be but is not limited to DLin-DMA, DLin-D-DMA, DLin-MC3-DMA, DLin-KC2-DMA and DODMA. The cationic lipid may be an ionizable lipid.

[0156] The structural lipid may be but is not limited to a sterol such as for example cholesterol.

[0157] The helper lipid is a non-cationic lipid. The helper lipid may comprise at least one fatty acid chain of at least 8C and at least one polar hcadgroup moiety.

[0158] Certain of the LNPs lack any phosphatidyl choline (PC) lipids (i.e., are free of phosphatidyl choline (PC)). Certain of the LNPs provided herein lack specific phosphatidyl choline lipids such as but not limiting to DSPC. Certain of the LNPs comprise a phosphatidyl choline analog, such analogs comprising modified head groups (e.g., a modified quaternary amine head group), modified core group, and / or modified lipid tail group. Such analogs may comprise a zwitterionic group that is a non-PC zwitterionic group. The helper lipid may be a lipid of any one or any combination of Formulae I, I-a, I-b, I-b-1, I-b-2, I-b-3, I-b-4, I-c, I-c-1, I-c-2, I-c-3, or II as provided herein.

[0159] Certain of the LNP may include a 1.2-distearoyl-sn-glycero-3-phosphocholine (DSPC) substitute or include a minimal amount of DSPC. In certain embodiments, the DSPC substitute is a lipid that is not a phospholipid.

[0160] Certain LNPs comprise other helper non-cationic lipids including for example oleic acid or oleic acid analogs. The helper lipid may be a lipid of Formula IV as provided herein. The oleic acid may be a substitute or may be in addition to another lipid in the LNP. As would be appreciated by one of skill in the art, modified versions of oleic acid or related fatty acids may be used as well.

[0161] In some instances, the LNP comprise PEGylated lipids or lipids conjugated to other stabilizing moieties (or stabilizers) such as but not limited to XTEN and PAS polypeptides. Thus, the disclosure contemplates and provides LNPs or formulations thereof that do not include PEG. In certain embodiments, the LNPs include HO-PEG. In other embodiments, the LNPs include a PEG substitute such as a different polymer.

[0162] When PEG is used as the stabilizer, it may be conjugated to a lipid and thus may be provided as PEG-c-DOMG or PEG-DMG, for example. The stabilizer, whether provided in a conjugated or an unconjugated form, may comprise 1.5 mol % of the LNP, or it may comprise less than 0.5 mol % of the LNP. For example, it may comprise less than 0.4 mol %, less than 0.3 mol %, less than 0.2 mol %, or less than 0.1 mol %.

[0163] In still other embodiments, LNPs may contain less than 0.5% molar ratio of PEG lipid to the other components. Thus, an LNP may comprise at least 0.0001%, at least 0.0005%, at least 0.001%, at least 0.005%, at least 0.01%, at least 0.05%, at least 0. 1%, at least 0.15%, at least 0.2%, at least 0.25%, at least 0.3%, at least 0.35%, at least 0.4%, at least 0.45%, and less than 0.5% (expressed as a molar percentage) of PEGylated lipid.

[0164] The LNP may comprise a PEGylatcd lipid of Formula III, including Formulae III-OH, II1-a-1, III-a-2, III-b-1, IIII-b-2, III-b-1-OH, III-b-2-OH, V, V-OH.

[0165] Certain of the LNPs provided herein comprise no or low levels of PEGylated lipids, including no or low levels of alkyl-PEGylated lipids, and may be referred to herein as being free of PEG or PEGylated lipid. Thus, some LNPs comprise less than 0.5 mol% PEGylated lipid. In some instances, PEG may be an alkyl-PEG such as methoxy-PEG..Still other LNPs comprise non-alkyl-PEG such as hydroxy-PEG, and / or non-alkyl-PEGylated lipids such as hydroxy-PEGylated lipids.

[0166] The PEGylated lipid may be a Cmpd420, a Cmpd396, a Cmpd394, Cmpd397, Cmpd395, Cmpd417, Cmpd418, or Cmpd419.

[0167] In some instances, the LNP may comprise about 50 mol %, 10 mol % helper lipid, 1.5 mol % PEGylated lipid, and 38.5 mol % structural lipid.

[0168] In some instances, the LNP may comprise about 50 mol %, 10 mol % helper lipid, less than 0.5 mol % PEGylated lipid, and 39.5 mol % structural lipid.

[0169] In some embodiments, the stabilizer is a non-PEG moiety such as an XTEN peptide that may or may not be conjugated to a lipid. The XTEN peptide is capable of forming a hydrated shell around the LNP due to its hydrophilic nature. It further serves to increase the half-life of the LNP, compared to an LNP lacking (or free of) any stabilizer. Unlike PEG, however, it is biodegradable and has been reported to be non-immunogenic. The XTEN peptide may have an amino acid sequence of MAEPAGSPTSTEEGTPGSGTASSSPGSSTPSGATGSPGASPGTSSTGS (SEQ ID NO:1) or MAEPAGSPTSTEEGASPGTSSTGSPGSSTPSGATGSPGSSTPSGATGS (SEQ ID NO:2). Other XTEN amino acid sequences are known in the art, including for example those reported in U.S. Patent No. 9,062,299. Examples of XTEN conjugated lipids include but are not limited to Cmpd431, and Cmpd432 and Cmpd433. Click chemistry may be used to conjugate the XTEN peptide to the lipid.

[0170] In some embodiments, the stabilizer is a non-PEG moiety such as a PAS peptide. A PAS peptide is a peptide comprising primarily if not exclusively proline, alanine and serine. Like PEG and XTEN peptides, the PAS peptide is capable of forming a hydrated shell around the LNP. It too serves to increase the half-life of an LNP, compared to an LNP lacking (or free of) a stabilizer. Unlike XTEN peptides, however, PAS peptides tend to be neutral in charge, and thus at least in this respect more similar to PEG. The PAS peptide may have an amino acid sequence of SAPSSPSPSAPSSPSPASPSSAPSSPSPSAPSSPSPASPSSAPSSPSPSAPSSPSPASPS (SEQ ID NO:3 or AASPAAPSAPPAAASPAAPSAPPAAASPAAPSAPPAAASPAAPSAPPA (SEQ ID NO:4). Other PAS amino acid sequences are known in the art, including for example, those reported in WO 2008155134.

[0171] Agents that inhibit immune responses induced by LNPs may also be used in the methods of the disclosure, together with a standard ABC inducing LNP or with a modified LNP of the invention. Agents that inhibit immune responses induced by LNPs, are compounds that inhibit the activation of a sensor, inhibit the interaction between an LNP and a sensor or between sensors (e.g, blocks interaction between pDC and B cells), and / or inhibit the production or activity of an effector. In some instances the agent will be specific for a particular sensor or effector. In other embodiments the agent that inhibits immune responses induced by LNPs functions to prevent the activation of multiple sensors by a more general mechanism, typically acting indirectly on other cellular components that can affect the sensors. An example of an agent that functions on multiple sensors indirectly is a miR binding site.

[0172] It has been discovered according to the invention that delivery of a miR binding site will inhibit an immune response associated with ABC and can be used to provide repeated dosing of a subject with an LNP during the window of susceptibility to ABC. The miR binding site may be incorporated into a therapeutic nucleic acid that is being delivered in the LNP. Alternatively the miR binding site may separately be incorporated into the same LNP that incorporates the therapeutic nucleic acid or into a different LNP. The miR binding site may be administered to the subject in a separate vehicle at the same or different time as the LNP and may or may not be incorporated into an LNP. In some embodiments the miR binding site may be a miR sponge.

[0173] Although Applicant is not bound by mechanism, it is believed that the miR binding site act to soak up endogenous, targeted miRNA of interest, preventing that miRNA from functioning in the cell. It is possible to target miRNA that play a positive role in regulation of immune cell function. By inhibiting the function of endogenous miRNA the miR binding site acts as an inhibitor to block the miRNA function and other downstream effects resulting from this targeting inhibition. The miRNA binding agent may also or alternatively be functioning by preventing protein translation in specific tissues or cells, such as the spleen or immune cells. By preventing translation of, for instance, an mRNA therapeutic encapsulated in the LNP, in specific tissues that are high in immune cells, the immune response in those tissues will be decreased, while not having an impact on mRNA expression in other tissues.

[0174] It has been demonstrated that introduction of miR binding sites such as miR 126 (highly abundant in pDC) results in a reduction in B cell activation, a reduction in pDC activation, a reduction in cytokine expression, such as IL6 and IFN-gamma, and a reduction in IgM relative to the response delivered by a corresponding LNP without the miR binding site.

[0175] In some embodiments the miR binding site is a miR 126, miR 155, and / or miR 142.3p binding site. In some embodiments, the mRNA can comprise at least one miR binding site to thereby reduce or inhibit ABC. The miR binding site may be found in, for instance, the 3' UTR of the mRNA. For example, in one embodiment, the mRNA comprises a miR-122 binding site, to thereby allow increased expression of a polypeptide encoded by the mRNA in a liver cancer cell (e.g., a hepatocellular carcinoma cell) as compared to a normal liver cell. and also comprises one or more miR binding sites, e.g., selected from the group consisting of miR-142, miR-146, miR-155, miR-126, miR-16, miK-21, miR-223, miR-24, miR-27.

[0176] A compound that inhibits the interaction between an LNP and a sensor as used herein will disrupt interaction between LNP and B1 cell, platelet or pDC. For instance, Some interactions between LNP and B1 cells are mediated through the CD36 receptor on the B1 cell and the PC on the LNP. The compound may block and neutralize the PC or the CD36. In some embodiments the compound is an antibody that recognizes and binds CD36, or an antigen-binding fragment or derivative thereof or a CD36 antagonist. A CD36 antagonist may be selected from the group consisting of antibodies or aptamers which bind to CD36 or fragments thereof; soluble ligands which bind to CD36 or fragments thereof; soluble CD36 which bind to its ligands; fusion polypeptides, peptides, small molecules, peptidomimetics inhibiting the CD36 activity; and nucleic acid molecules interfering specifically with CD36 expression. Such CD36 antagonist is preferably an antagonist which, preferably specifically, recognizes and binds to a CD36 molecule or fragment thereof, and is preferably selected from the group consisting of an antibody or an aptamer which specifically recognizes and binds to CD36 or a fragment thereof, a nucleic acid molecule interfering specifically with CD36 expression, and a small molecule inhibiting the CD36 activity. More preferably, said CD36 antagonist is a function-blocking monoclonal antibody against CD36. In other embodiments, said CD36 antagonist is a small molecule selected from the group consisting of salvianolic acid B, rosmarinic acid, sodium danshensu, 3-cinnamoyl indole, 13 pentyl berberine, hexarelin, nanoblockers, statins or antioxidants such as alpha-tocopherol and SS peptides, Sulfo-N-succinimidyl oleate and Ursolic acid, and any combination thereof. Alternatively, the CD36 antagonist may comprise an antibody that recognizes and binds CD36, or an antigen-binding fragment or derivative thereof. Preferably, said antibody or antigen-binding fragment or derivative thereof, is directed against the extracellular domain of CD36. Said antibody may be a full-length antibody. Preferably, said antibody is a monoclonal antibody. The antibody may be of the IgG, IgE or IgD type, preferably of the IgG type. The antibody may be a humanized, chimeric or human antibody. The antibody may also be camelid heavy-chain antibody, and in particular humanized camclid heavy-chain antibody. Preferably, said antibody, or antigen-binding fragment or derivative thereof, is bivalent. In particular, the antigen-binding fragment is selected from the group consisting of F(ab')2 di-scFvs, sc(Fv) 2 fragment, (VHH) 2 fragment and diabody.

[0177] A compound that inhibits the activity of an effector is a compound that prevents an effector from being produced by a sensor or functioning. For instance the agent may inhibit the production of natural IgM that binds the LNPs by interfering with the synthesis pathway in a B1 cell. Alternatively the agent may neutralize such natural IgMs or IgG. The agent may be an antibody or antigen-binding portion thereof, that binds to natural IgM or IgG and neutralizes it. Alternatively, the agent may interfere with the binding of IgM or IgG to its target. In other embodiments the agent that inhibits immune responses induced by the LNPs is an agent that inhibits IL6 activity. Agents that inhibit IL6 activity include for instance, antibodies, fragments thereof, specific humanized antibodies and fragments and variants thereof capable of binding to IL-6 and / or the IL-6 / IL-6R complex. These antibodies may bind soluble IL-6 or cell surface expressed IL-6.Lipid Nanoparticles, generally

[0178] In some embodiments, the lipid nanoparticle comprises a cationic lipid, a PEG-modified lipid, a sterol and a non-cationic lipid. In some embodiments, the lipid nanoparticle carrier comprising a molar ratio of about 20-60% cationic lipid: 5-25% non-cationic lipid: 25-55% sterol; and 0.5-15% PEG-modified lipid. In some embodiments, the cationic lipid is an ionizable cationic lipid. In some embodiments, the non-cationic lipid is a neutral lipid. In some embodiments, the sterol is a cholesterol. In some embodiments, the cationic lipid is selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxotane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-I-yl)9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319). In some embodiments, the lipid nanoparticle has a polydiversity value of less than 0.4. In some embodiments, the lipid nanoparticle has a net neutral charge at a neutral pH. In some embodiments, the lipid nanoparticle has a mean diameter of 50-200nm.

[0179] Lipid nanoparticles may comprise one or more lipid species, including, but not limited to, cationic / ionizable lipids, non-cationic lipids, structural lipids, phospholipids, and helper lipids. Any of these lipids may be conjugated to polyethylene glycol (PEG) and thus may be referred to as PEGylated lipids or PEG-modified lipids.

[0180] The formation of the lipid nanoparticle (LNP) may be accomplished by methods known in the art and / or as described in U.S. Pub. No. 2012 / 0178702, herein

[0181] A lipid nanoparticle formulation may be influenced by, but not limited to, the selection of the cationic lipid component, the degree of cationic lipid saturation, the selection of the non-cationic lipid component, the degree of non-cationic lipid saturation, the selection of the structural lipid component, the nature of the PEGylation, ratio of all components and biophysical parameters such as size. In certain non-limiting examples, a LNP comprises tour basic components: (1) a cationic lipid; (2) a non-cationic lipid (e.g., a phospholipid such as DSPC); (3) a structural lipid (e.g., a sterol such as cholesterol); and (4) PEG or a PEG-modified lipid. In one example by Semple el al. (Nature Biotech. 2010 28:172-176), the lipid nanoparticle formulation is composed of molar ratios as follows: 57.1 % cationic lipid, 7.1% dipalmitoylphosphatidylcholine, 34.3 % cholesterol, and 1.4% PEG-c-DMA. As another example, changing the composition of the cationic lipid can more effectively deliver siRNA to various antigen presenting cells (Basha el al., Mol Ther. 2011 19:2186-2200).

[0182] The lipid nanoparticles described herein comprise one or more lipids. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid and a non-cationic lipid. In certain embodiments, the LNP formulation comprises a cationic lipid and a DSPC substitute. In certain embodiments, the LNP formulation comprises a cationic lipid and a fatty acid. In certain embodiments, the LNP formulation comprises a cationic lipid and oleic acid. In certain embodiments, the LNP formulation comprises a cationic lipid and an analog of oleic acid.

[0183] Cationic lipids are positively charged lipids that may associate with nucleic acids in the lipid / LNP-based delivery systems. A positive charge on the LNP promotes association with the negatively charged cell membrane to enhance cellular uptake. Cationic lipids may also combine with negatively charged lipids to induce nonbilayer structures that facilitate intracellular delivery. Suitable cationic lipids for use in making the LNPs disclosed herein can be ionizable cationic lipids, for example, amino lipid, and those disclosed herein.

[0184] In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, a non-cationic lipid, and a structural lipid. In certain embodiments, the LNP formulation comprises a cationic lipid, a fatty acid, and a structural lipid. In certain embodiments, the LNP formulation comprises a cationic lipid, oleic acid, and a structural lipid. In certain embodiments, the LNP formulation comprises a cationic lipid, an analog of oleic acid, and a structural lipid. In certain embodiments, the LNP formulation comprises a cationic lipid, a fatty acid, and a sterol. In certain embodiments, the LNP formulation comprises a cationic lipid, oleic acid, and a sterol. In certain embodiments, the LNP formulation comprises a cationic lipid, oleic acid, and cholesterol.

[0185] In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid. a non-cationic lipid, and PEG or a PEG lipid. In certain embodiments, the LNP formulation comprises a cationic lipid, a non-cationic lipid, and a PEG lipid. In certain embodiments, the LNP formulation comprises a cationic lipid, a non-cationic lipid, and a PEG-OH lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, a non-cationic lipid, and a PEG-OH lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, a fatty acid, and a PEG-OH lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, oleic acid, and a PEG-OH lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, an analog of oleic acid, and a PEG-OH lipid.

[0186] In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid. a non-cationic lipid (e.g., a phospholipid or fatty acid), a structural lipid, and a PEG lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, a non-cationic lipid (e.g., phospholipid or fatty acid), a structural lipid, and a PEG-OH lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, a non-cationic lipid (e.g., phospholipid or fatty acid), and structural lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid. a fatty acid (e.g., oleic acid or an analog thereof), a structural lipid, and a PEG lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, a fatty acid (e.g., oleic acid or an analog thereof), a structural lipid, and a PEG-OH lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, oleic acid, a structural lipid (e.g., a sterol), and a PEG-OH lipid. In certain embodiments, the lipid nanoparticle formulation comprises a cationic lipid, oleic acid, and a structural lipid (e.g., cholesterol). In certain embodiments, the lipid nanoparticle formulation comprises one or more cationic or non-cationic lipids, a fatty acid (e.g., oleic acid), and a PEG lipid. In certain embodiments, the lipid nanoparticle formulation comprises one or more cationic or non-cationic lipids, a fatty acid (e.g., oleic acid), and a PEG-OH lipid.

[0187] In some embodiments, the LNP comprises a fatty acid. In certain embodiments, the fatty acid is a monounsaturated fatty acid. In certain embodiments, the fatty acid is a polyunsaturated fatty acid. In some embodiments, the LNP comprises oleic acid. In certain embodiments, the lipid nanoparticle formulation comprises one or more cationic or non-cationic lipids, and a fatty acid (e.g., oleic acid). In certain embodiments, the lipid nanoparticle formulation comprises one or more cationic or non-cationic lipids, and oleic acid. In certain embodiments, when the LNP includes oleic acid, the LNP does not include a phospholipid. In certain embodiments, when the LNP includes oleic acid, the LNP does not include DSPC. In certain embodiments, when the LNP includes a fatty acid, the LNP does not include a phospholipid. In certain embodiments, when the LNP includes a fatty acid, the TNP does not include DSPC.

[0188] In some embodiments, the LNP comprises PEG-OH lipids. In certain embodiments, the lipid nanoparticle formulation comprises one or more cationic or non-cationic lipids. and a PEG-OH lipid.

[0189] In some embodiments, lipid nanoparticle formulations may comprise, in molar percentages, 35 to 45% cationic lipid, 40% to 50% cationic lipid, 50% to 60% cationic lipid and / or 55% to 65% cationic lipid. In some embodiments, the ratio of lipid to nucleic acid (e.g., mRNA) in lipid nanoparticles may be 5:1 to 20:1, 10:1 to 25:1, 15:1 to 30:1 and / or at least 30:1.

[0190] In some embodiments, the ratio of PEG in the lipid nanoparticle formulations may be increased or decreased and / or the carbon chain length of the PEG lipid may be modified from C14 to C18 to alter the pharmacokinetics and / or biodistribution of the lipid nanoparticle formulations. In certain embodiments, lipid nanoparticle formulations may contain 0.5% to 3.0%, 1.0% to 3.5%, 1.5% to 4.0%, 2.0% to 4.5%, 2.5% to 5.0%, and / or 3.0% to 6.0% of the lipid molar ratio of PEG lipid to the other components. As a non-limiting example, lipid nanoparticle formulations may contain 0.5% to 3.0%, 1.0% to 3.5%, 1.5% to 4.0%, 2.0% to 4.5%, 2.5% to 5.0%, and / or 3.0% to 6.0% of the lipid molar ratio of PEG-c-DOMG (R-3-[(ω-methoxy-poly(ethyleneglycol)2000)carbamoyl)]-1,2-dimyristyloxypropyl-3-amine) (also referred to herein as PEG-DOMG) as compared to the cationic lipid, DSPC, and cholesterol. In some embodiments, the PEG-c-DOMG may be replaced with a PEG lipid such as, but not limited to, PEG- DSG (1,2-distearoyl-sn-glycerol, methoxypolyethylene glycol), DMG-PEG (1,2-dimyristoyi-sn-glycerol) and / or PEG-DPG (1,2-dipalmitoyl-sn-glycerol, methoxypolyethylene glycol). The cationic lipid may be selected from any lipid known in the art such as, but not limited to, DLin-MC3-DMA, DLin-DMA, C12-200, and DLin-KC2-DMA. In certain embodiments, the lipid nanoparticle does not contain a PEG lipid. In certain embodiments, the lipid nanoparticle contains a PEG lipid substitute such as a PEG-OH lipid. Incorporation of PEG-OH lipids in the nanoparticle formulation can improve the pharmacokinetics and / or biodistribution of the lipid nanoparticle formulations. For example, incorporation of PEG-OH lipids in the nanoparticle formulation can reduce the ABC effect. In certain embodiments, lipid nanoparticle formulations may contain 0.5% to 3.0%, 1.0% to 3.5%, 1.5% to 4.0%, 2.0% to 4.5%, 2.5% to 5.0%, and / or 3.0% to 6.0% of the lipid molar ratio of PEG-OH lipid to the other components (e.g., the cationic, neutral, and structural lipids).

[0191] In some embodiments, a LNP formulation is a nanoparticle that comprises at least one lipid. In certain embodiments, the lipids is selected from cationic / ionizable lipids, non-cationic lipids (e.g., tatty acids and phospholipids), PEG lipids, structural lipids (e.g., sterols), and PEG-OH lipids. The lipid may be selected from, but is not limited to, DLin-DMA, DLin-K-DMA, 98N12-5, C12-200, DLin-MC3-DMA, DLin-KC2-DMA, DODMA, PLGA. PEG, PEG-DMG, PEGylatcd lipids, and amino alcohol lipids. In some embodiments, the lipid may be a cationic lipid, such as, but not limited to. DLin-DMA, DLin-D-DMA, DLin-MC3-DMA. DLin-KC2-DMA, DODMA, and amino alcohol lipids. The amino alcohol cationic lipid may be the lipids described in and / or made by the methods described in US Patent Publication No. US2013 / 0150625. As a non-limiting example, the cationic lipid may be 2-amino-3-[(9Z,12Z)-octadeca-9,12-dien-I-yloxy]-2-([(9Z,27,)-octadeca-9,12-dien-1-yloxy]methyl)propan-1-ol (Compound 1 in US2013 / 0150625); 2-amino-3-[(9Z)-octadec-9-en-1 -yloxy]-2-{[(9Z)-octadec-9-en-1-yloxy]methyl}propan-1-ol (Compound 2 in US20130150625); 2-amino-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]-2-[(octytoxy)mcthyt]propan-1-ol (Compound 3 in US2013 / 01 50625); and 2-(dimethylamino)-3-[(9Z, 12Z)-octadeca-9,12-dien-1-yloxy]-2-{[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]methyl}propan-1-ol (Compound 4 in US2013 / 0150625); or any pharmaceutically acceptable salt or stereoisomer thereof.

[0192] Lipid nanoparticle formulations can comprise a lipid, in particular, an ionizable cationic lipid, for example, 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), or di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319), and further comprise a non-cationic lipid (e.g., phospholipid or fatty acid), a structural lipid (e.g., a sterol such as cholesterol), and a molecule capable of reducing particle aggregation, for example, a PEG or PEG-modified lipid (e.g., PEG-OH lipid). In certain embodiments, the formulation does not contain the PEG lipid.

[0193] In some embodiments, the LNP formulation consists essentially of a molar ratio of 20-60% cationic lipid; 5-25% non-cationic lipid; 25-55% sterol; 0.5-15% PEG lipid. In some embodiments, the LNP formulation consists essentially of a molar ratio of 20-60% cationic lipid; 5-25% non-cationic lipid; 25-55% sterol; 0.5-15% PEG-OH lipid. In some embodiments, the LNP formulation consists essentially of in a molar ratio of 20-60% cationic lipid; 5-25% non-cationic lipid; and 25-55% sterol. In certain embodiments, the non-cationic lipid is a fatty acid. In certain embodiments, the non-cationic lipid is oleic acid or an analog thereof. In certain embodiments, the PEG lipid is a PEG-OH lipid.

[0194] In some embodiments, a lipid nanoparticle formulation consists essentially of (i) at least one lipid selected from the group consisting of 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioatc (L319); (ii) a non-cationic lipid selected from DSPC, DPPC, POPC, DOPE, and SM; (iii) a sterol, e.g., cholesterol; and (iv) a PEG-lipid, e.g., PEG-DMG or PEG-cDMA, in a molar ratio of 20-60% cationic lipid; 5-25% non-cationic lipid; 25-55% sterol; 0.5-15% PEG-lipid.

[0195] In some embodiments, a lipid nanoparticle formulation consists essentially of (i) at least one lipid selected from the group consisting of 2.2-dilinoleyl-4-dimethylaminocthyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimcthylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319); (ii) a non-cationic lipid as a DSPC substitute (e.g., a different phospholipid, or a fatty acid); (iii) a structural lipid (e.g., a sterol such as cholesterol); and (iv) a PEG-lipid or a PEG-OH lipid (e.g., PEG-DMG or PEG-cDMA), in a molar ratio of 20-60% cationic lipid; 5-25% DSPC substitute; 25-55% structural lipid; 0.5-15% PEG-lipid.

[0196] In some embodiments, a lipid nanoparticle formulation includes 25% to 75% on a molar basis of a cationic lipid. The cationic lipid may be selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319), e.g., 35 to 65%, 45 to 65%, 60%, 57.5%, 50% or 40% on a molar basis.

[0197] In some embodiments, a lipid nanoparticle formulation includes 0.5% to 15% on a molar basis of the non-cationic lipid, e.g., 3 to 12%, 5 to 10% or 15%, 10%, or 7.5% on a molar basis. In certain embodiments, the non-cationic lipid is a phospholipid. In certain embodiments, the non-cationic lipid is a DSPC substitute (e.g., a phospholipid other than DSPC, or a fatty acid). In certain embodiments, the non-cationic lipid is a fatty acid (e.g., oleic acid or an analog thereof). Other examples of non-cationic lipids include, without limitation, POPC, DPPC, DOPE and SM. In some embodiments, a lipid nanoparticle formulation includes 0.5% to 15% on a molar basis of a fatty acid, e.g., 3 to 12%. 5 to 10% or 15%, 1 0%, or 7.5% on a molar basis. In some embodiments, a lipid nanoparticle formulation includes 0.5% to 15% on a molar basis of oleic acid, e.g., 3 to 12%, 5 to 10% or 15%, 10%. or 7.5% on a molar basis. In some embodiments, a lipid nanoparticle formulation includes 0.5% to 15% on a molar basis of an analog of oleic acid, e.g., 3 to 12%, 5 to 10% or 15%, 10%, or 7.5% on a molar basis.

[0198] In some embodiments, the formulation includes 5% to 50% on a molar basis of the structural lipid, e.g., 15 to 45%, 20 to 40%, 40%, 38.5%, 35%, or 31% on a molar basis. In some embodiments, the formulation includes 5% to 50% on a molar basis of a sterol, e.g., 15 to 45%, 20 to 40%, 40%, 38.5%, 35%, or 31% on a molar basis. A non-limiting example of a sterol is cholesterol.

[0199] In some embodiments, a lipid nanoparticle formulation includes 0.5% to 20% on a molar basis of the PEG or PEG-modified lipid, e.g., 0.5 to 10%, 0.5 to 5%, 1.5%, 0.5%, 1.5%, 3.5%, or 5% on a molar basis. In some embodiments, a PEG or PEG-modified lipid comprises a PEG molecule of an average molecular weight of 2,000 Da. In some embodiments, a PEG or PEG modified lipid comprises a PEG molecule of an average molecular weight of less than 2,000, for example, around 1,500 Da, around 1,000 Da, or around 500 Da. Non-limiting examples of PEG-modified lipids include PEG-distearoyl glycerol (PEG-DMG) (also referred herein as Cmpd422), PEG-cDMA (further discussed in Reyes et al. J. Controlled Release, 107, 276-287 (2005)). As described herein, any PEG lipids or PEG-modified lipids may be PEG-OH lipids. In some embodiments, a lipid nanoparticle formulation includes 0.5% to 20% on a molar basis of a PEG-OH lipid, e.g., 0.5 to 10%, 0.5 to 5%, 1.5%, 0.5%, 1.5%, 3.5%, or 5% on a molar basis.

[0200] In some embodiments, lipid nanoparticle formulations include 25-75% of a cationic lipid, 0.5-1 5% of the non-cationic lipid; 5-50% of the structural lipid, and 0.5-20% of the PEG or PEG-modified lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 25-75% of a cationic lipid, 0.5-15% of the non-cationic lipid; 5-50% of the structural lipid, and 0.5-20% of a PEG-OH lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 25-75% of a cationic lipid, 0.5-15% of the non-cationic lipid, and 5-50% of the structural lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 25-75% of a cationic lipid selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319).

[0201] In some embodiments, lipid nanoparticle formulations include 35-65% of a cationic lipid, 3-12% of the non-cationic lipid, 15-45% of the structural lipid, and 0.5-10% of the PEG or PEG-modified lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 35-65% of a cationic lipid, 3-12% of the non-cationic lipid, 15-45% of the structural lipid, and 0.5-10% of the PEG-OH lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 35-65% of a cationic lipid, 3-12% of the non-cationic lipid, and 15-45% of the structural lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 35-65% of a cationic lipid selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319).

[0202] In some embodiments, lipid nanoparticle formulations include 45-65% of a cationic lipid, 5-10% of the non-cationic lipid, 25-40% of the structural lipid, and 0.5-10% of the PEG or PEG-modified lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 45-65% of a cationic lipid, 5-10% of the non-cationic lipid, 25-40% of the structural lipid, and 0.5-10% of a PEG-OH lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 45-65% of a cationic lipid, 5-10% of the non-cationic lipid, and 25-40% of the structural lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 45-65% of a cationic lipid selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319).

[0203] In some embodiments, lipid nanoparticle formulations include 60% of a cationic lipid, 7.5% of the non-cationic lipid, 31 % of a structural lipid, and 1.5% of the PEG or PEG-modificd lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 60% of a cationic lipid, 7.5% of the non-cationic lipid, 31% of a structural lipid, and 1.5% of a PEG-OH lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 60% of a cationic lipid, 9% of the non-cationic lipid, and 31% of a structural lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 60% of a cationic lipid selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and d1((Z)-non-2-en-1-yl) 9-((4-(dimethylammo)butanoyl)oxy)heptadecanedioate (L319).

[0204] In some embodiments, lipid nanoparticle formulations include 50% of a cationic lipid, 10% of the non-cationic lipid, 38.5 % of the structural lipid, and 1.5% of the PEG or PEG-modified lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 50% of a cationic lipid, 10% of the non-cationic lipid, 38.5 % of a structural lipid. and 1.5% of a PEG-OH lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 50% of a cationic lipid, 10% of the non-cationic lipid, and 40% of a structural lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 50% of a cationic lipid selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319).

[0205] In some embodiments, lipid nanoparticle formulations include 40% of a cationic lipid, 15% of the non-cationic lipid, 40% of the structural lipid, and 5% of the PEG or PEG-modified lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 40% of a cationic lipid, 15% of the non-cationic lipid, 40% of the structural lipid, and 5% of a PEG-OH lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 40% of a cationic lipid, 20% of the non-cationic lipid, 40% of the structural lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 40% of a cationic lipid selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1,3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioate (L319).

[0206] In some embodiments, lipid nanoparticle formulations include 57.2% of a cationic lipid, 7.1% of the non-cationic lipid 34.3% of the sterol, and 1.4% of the PEG or PEG-modified lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 57.2% of a cationic lipid, 7.1% of the non-cationic lipid, 34.3% of the structural lipid, and 1.4% of the PEG-OH lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 57.2% of a cationic lipid, 8.5% of the non-cationic lipid, and 34.3% of the structural lipid on a molar basis. In some embodiments, lipid nanoparticle formulations include 57.2% of a cationic lipid selected from 2,2-dilinoleyl-4-dimethylaminoethyl-[1.3]-dioxolane (DLin-KC2-DMA), dilinoleyl-methyl-4-dimethylaminobutyrate (DLin-MC3-DMA), and di((Z)-non-2-en-1-yl) 9-((4-(dimethylamino)butanoyl)oxy)heptadecanedioale (L319).

[0207] In some embodiments, lipid nanoparticle formulations consists essentially of a lipid mixture in molar ratios of 20-70% cationic lipid; 5-45% non-cationic lipid; 20-55% structural lipid; 0.5-15% PEG-modified lipid. In some embodiments, lipid nanoparticle formulations consists essentially of a lipid mixture in molar ratios of 20-70% cationic lipid; 5-45% non-cationic lipid (e.g., phospholipid or fatty acid); 20-55% structural lipid; and 0.5-15% PEG-OH lipid. In some embodiments, lipid nanoparticle formulations consists essentially of a lipid mixture in molar ratios of 20-70% cationic lipid; 5-45% non-cationic lipid (e.g., phospholipid or fatty acid); 20-55% structural lipid (e.g., sterols); and 0.5-15% PEG-OH lipid. In some embodiments, lipid nanoparticle formulations consists essentially of a lipid mixture in molar ratios of 20-70% cationic lipid; 5-45% non-cationic lipid (e.g., phospholipid or fatty acid); and 20-55% structural lipid (e.g., sterols). In some embodiments, lipid nanoparticle formulations consists essentially of a lipid mixture in molar ratios of 20-70% cationic lipid; 5-45% fatty acid (e.g., oleic acid or analog thereof); 20-55% structural lipid (e.g., sterols); and 0.5-15% PEG-OH lipid. In some embodiments, lipid nanoparticle formulations consists essentially of a lipid mixture in molar ratios of 20-70% cationic lipid; 5-45% fatty acid (e.g., oleic acid or analog thereof); and 20-55% structural lipid (e.g., sterols). In some embodiments, lipid nanoparticle formulations consists essentially of a lipid mixture in molar ratios of 20-70% cationic lipid; 5-45% oleic acid; 20-55% structural lipid (e.g., sterols); and 0.5-15% PEG-OH lipid. In some embodiments, lipid nanoparticle formulations consists essentially of a lipid mixture in molar ratios of 20-70% cationic lipid; 5-45% oleic acid; and 20-55% structural lipid (e.g., sterols).

[0208] In some embodiments, the molar lipid ratio is 50 / 10 / 38.5 / 1.5 (mol% cationic lipid / non-cationic lipid / structural lipid / PEG lipid). In some embodiments, the molar lipid ratio is 57.2 / 7.1134.3 / 1.4 (mol% cationic lipid / non-cationic lipid / structural lipid / PEG lipid). In some embodiments, the molar lipid ratio is 40 / 15 / 40 / 5 (mol% cationic lipid / non-cationic lipid / structural lipid / PEG lipid). In some embodiments, the molar lipid ratio is 50 / 10 / 35 / 4.5 / 0.5 (mol% cationic lipid / non-cationic lipid / structural lipid / PEG lipid). In some embodiments, the molar lipid ratio is 50 / 10 / 35 / 5 (mol% cationic lipid / non-cationic lipid / structural lipid / PEG lipid). In some embodiments, the molar lipid ratio is 40 / 10 / 40 / 10 (mol% cationic lipid / non-cationic lipid / structural lipid / PEG lipid). In some embodiments, the molar lipid ratio is 35 / 15 / 40 / 10 (mol% cationic lipid / non-cationic lipid / structural lipid / PEG lipid). In some embodiments, the molar lipid ratio is 52 / 13 / 30 / 5(mol% cationic lipid / non-cationic lipid / structural lipid / PEG lipid). As described herein, any non-cationic lipid may be a DSPC substitute such as a non-DSPC phospholipid or a fatty acid (e.g., oleic acid). As described herein, any PEG lipid may be a PEG-OH lipid.

[0209] Non-limiting examples of lipid nanoparticle compositions and methods of making them are described, for example, in Semple et al. (2010) Nat. Biotechnol. 28:172-176; Jayarama et al. (2012), Angew. Chem. Int. Ed, 51: 8529-8533; and Maier el al. (2013) Molecular Therapy 21, 1570-1578

[0210] In some embodiments, lipid nanoparticle formulations may comprise a cationic lipid, a PEG lipid (e.g., PEG-OH lipid) and optionally comprise a non-cationic lipid (e.g., phospholipid or fatty acid). In some embodiments, lipid nanoparticle formulations may comprise a cationic lipid, a PEG lipid (e.g., PEG-OH lipid) and a structural lipid (e.g., a sterol) and optionally comprise a non-cationic lipid (e.g., phospholipid or fatty acid).

[0211] Lipid nanoparticles described herein may comprise 2 or more components (e.g., lipids), not including the payload. In certain embodiments, the LNP comprises two components (e.g., lipids), not including the payload. In certain embodiments, the lipid nanoparticle comprises 5 components (e.g., lipids), not including the payload. In certain embodiments, the LNP comprises 6 components (e.g., lipids), not including the payload.

[0212] In some embodiments, the lipid nanoparticle formulations described herein may be four component lipid nanoparticles. A 4 component LNP may comprise four different lipids selected from any described herein. The four components do not include the payload. The lipid nanoparticle may comprise a cationic lipid, a non-cationic lipid, a PEG lipid, and a structural lipid. In certain embodiments, the lipid nanoparticle comprises a cationic lipid, a fatty acid, a PEG lipid, and a structural lipid. In certain embodiments, the lipid nanoparticle comprises a cationic lipid, a fatty acid, a PEG-OH lipid, and a structural lipid.

[0213] In some embodiments, the lipid nanoparticle formulations described herein may be three component lipid nanoparticles. A three component LNP may comprise three different lipids described herein. The lipid nanoparticle may comprise a cationic lipid, a non-cationic lipid (e.g., phospholipid or fatty acid), and a structural lipid. In certain embodiments, the lipid nanoparticle comprises a cationic lipid, a fatty acid, and a structural lipid. In certain embodiments, the lipid nanoparticle comprises a cationic lipid, a phospholipid, and a structural lipid.

[0214] In some embodiments, a nanoparticle (e.g., a lipid nanoparticle) has a mean diameter of 10-500 nm, 20-400 nm, 30-300 nm, or 40-200 nm. In some embodiments, a nanoparticle (e.g., a lipid nanoparticle) has a mean diameter of 50-150 nm, 50-200 nm, 80-100 nm. or 80-200 nm.

[0215] In one embodiment, the LNP formulation may be formulated by the methods described in International Publication Nos. WO2011127255 or WO2008103276. As a non-limiting example, LNP formulations as described in WO2011127255 and / or WO2008103276.

[0216] In one embodiment, the lipid nanoparticle may be formulated by the methods described in US Patent Publication No US2013 / 0156845 or International Publication No WO2013 / 093648 or WO2012024526.

[0217] The lipid nanoparticles described herein may be made in a sterile environment by the system and / or methods described in US Patent Publication No. US20130164400.

[0218] In one embodiment, the LNP formulation may be formulated in a nanoparticle such as a nucleic acid-lipid particle described in US Patent No. 8,492,359.

[0219] As a non-limiting example, the lipid particle may comprise one or more active agents or therapeutic agents (e.g., RNA); one or more cationic lipids comprising from about 50 mol% to about 85 mol% of the total lipid present in the particle; one or more non-cationic lipid lipids comprising from about 13 mol% to about 49.5 mol% of the total lipid present in the particle; and one or more structural lipids that inhibit aggregation of particles comprising from about 0.5 mol% to about 2 mol% of the total lipid present in the particle.

[0220] In one embodiment, the LNP formulation may be formulated by the methods described in International Publication Nos. WO2011127255 or WO2008103276. As a non-limiting example, LNP formulations as described in WO2011127255 and / or WO2008103276; the contents of each of which are herein incorporated by reference in their entirety. In one embodiment, LNP formulations described herein may comprise a polycationic composition. As a non-limiting example, the polycationic composition may be selected from formula 1-60 of US Patent Publication No. US20050222064.

[0221] In some embodiments, LNPs comprise the lipid KL52 (an amino-lipid disclosed in U.S. Application Publication No. 2012 / 0295832). Activity and / or safety (as measured by examining one or more of ALT / AST, white blood cell count and cytokine induction) of LNP administration may be improved by incorporation of such lipids. LNPs comprising KL52 may be administered intravenously and / or in one or more doses. In some embodiments, administration of LNPs comprising KL52 results in equal or improved mRNA and / or protein expression as compared to LNPs comprising MC3.

[0222] As a non-limiting example, the LNP may include a cationic peptide or a polypeptide such as, but not limited to, polylysine, polyornithine and / or polyarginine and the cationic peptides described in International Pub. No. WO2012013326 or US Patent Pub. No. US20130142818. In some embodiments, the lipid nanoparticle includes a non-cationic lipid such as, but not limited to, cholesterol or dioleoyl phosphatidylethanolamine (DOPE).

[0223] In some embodiments, the lipid nanoparticles described herein can have a diameter from below 0.1 um up to 100 nm such as, but not limited to, less than 0.1 um, less than 1.0 um, less than 5 um, less than 10 um, less than 15 um, less than 20 um, less than 25 um, less than 30 um, less than 35 um, less than 40 um, less than 50 um, less than 55 um, less than 60 um, less than 65 um, less than 70 um, less than 75 um, less than 80 um, less than 85 um. less than 90 um, less than 95 um, less than 100 um, less than 125 um, less than 150 um, less than 175 um, less than 200 um, less than 225 um, less than 250 um, less than 275 um, less than 300 um, less than 325 um, less than 350 um, less than 375 um, less than 400 um, less than 425 um, less than 450 um, less than 475 um, less than 500 um, less than 525 um, less than 550 um, less than 575 um, less than 600 um, less than 625 um, less than 650 um, less than 675 um, less than 700 um, less than 725 um, less than 750 um, less than 775 um, less than 800 um, less than 825 um, less than 850 um, less than 875 um, less than 900 um, less than 925 um, less than 950 um, less than 975 um.

[0224] In another embodiment, LNPs may have a diameter from about 1 nm to about 100 nm, from about 1 nm to about 10 nm, about 1 nm to about 20 nm. from about 1 nm to about 30 nm. from about 1nm to about 40 nm, from about 1nm to about 50 nm, from about 1nm to about 60 nm, from about 1 nm to about 70 nm, from about 1nm to about 80 nm, from about 1 nm to about 90 nm, from about 5 nm to about from 100 nm, from about 5 nm to about 10 nm, about 5 nm to about 20 nm, from about 5 nm to about 30 nm, from about 5 nm to about 40 nm, from about 5 nm to about 50 nm, from about 5 nm to about 60 nm, from about 5 nm to about 70 nm, from about 5 nm to about 80 nm, from about 5 nm to about 90 nm, about 10 to about 50 nM, from about 20 to about 50 nm, from about 30 to about 50 nm, from about 40 to about 50 nm, from about 20 to about 60 nm, from about 30 to about 60 nm, from about 40 to about 60 nm, from about 20 to about 70 nm, from about 30 to about 70 nm, from about 40 to about 70 nm, from about 50 to about 70 nm, from about 60 to about 70 nm, from about 20 to about 80 nm, from about 30 to about 80 nm, from about 40 to about 80 nm, from about 50 to about 80 nm. from about 60 to about 80 nm, from about 20 to about 90 nm, from about 30 to about 90 nm, from about 40 to about 90 nm, from about 50 to about 90 nm, from about 60 to about 90 nm and / or from about 70 to about 90 nm. Each possibility represents a separate embodiment of the present invention.

[0225] A nanoparticle composition may be relatively homogenous. A polydispersity index may be used to indicate the homogeneity of a nanoparticle composition, e.g., the particle size distribution of the nanoparticle compositions. A small (e.g., less than 0.3) polydispersity index generally indicates a narrow particle size distribution. A nanoparticle composition may have a polydispersity index from about 0 to about 0.25, such as 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, or 0.25. In some embodiments, the polydispersity index of a nanoparlicle composition may be from about 0.10 to about 0.20. Each possibility represents a separate embodiment of the present invention.

[0226] The zeta potential of a nanoparticle composition may be used to indicate the electrokinetic potential of the composition. For example, the zeta potential may describe the surface charge of a nanoparticle composition. Nanoparticle compositions with relatively low charges, positive or negative, are generally desirable, as more highly charged species may interact undesirably with cells, tissues, and other elements in the body. In some embodiments, the zeta potential of a nanoparticle composition may be from about -10 mV to about +20 mV, from about -10 mV to about +15 mV, from about -10 mV to about +10 mV, from about -10 mV to about +5 mV, from about -10 mV to about 0 mV, from about -10 mV to about -5 mV, from about -5 mV to about +20 mV, from about -5 mV to about +15 mV, from about -5 mV to about +10 mV, trom about -5 mV to about +5 mV, from about -5 mV to about 0 mV, from about 0 mV to about +20 mV, from about 0 mV to about +15 mV, from about 0 mV to about +10 mV, from about 0 mV to about +5 mV, from about +5 mV to about +20 mV, from about +5 mV to about +15 mV, or from about +5 mV to about +10 mV. Each possibility represents a separate embodiment of the present invention.

[0227] The efficiency of encapsulation of a therapeutic agent describes the amount of therapeutic agent that is encapsulated or otherwise associated with a nanoparticle composition after preparation, relative to the initial amount provided. The encapsulation efficiency is desirably high (e.g., close to 100%). The encapsulation efficiency may be measured, for example, by comparing the amount of therapeutic agent in a solution containing the nanoparticle composition before and after breaking up the nanoparticle composition with one or more organic solvents or detergents. Fluorescence may be used to measure the amount of free therapeutic agent (e.g., nucleic acids) in a solution. For the nanoparticle compositions described herein, the encapsulation efficiency of a therapeutic agent may be at least 50%, for example 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%. 98%, 99%, or 100%. In some embodiments, the encapsulation efficiency may be at least 80%. In certain embodiments, the encapsulation efficiency may be at least 90%. Each possibility represents a separate embodiment of the present invention.

[0228] A nanoparticle composition may optionally comprise one or more coatings. For example, a nanoparticle composition may be formulated in a capsule, film, or tablet having a coating. A capsule, film, or tablet including a composition described herein may have any useful size, tensile strength, hardness, or density.

[0229] In some embodiments, such LNPs arc synthesized using methods comprising microfluidic mixers. Exemplary microfluidic mixers may include, but are not limited to a slit interdigitial micromixer including, but not limited to those manufactured by Microinnova (Allerheiligen bei Wildon, Austria) and / or a staggered herringbone micromixer (SHM) (Zhigaltsev, I.V. et al., Bottom-up design and synthesis of limit size lipid nanoparticle systems with aqueous and triglyceride cores using millisecond microfluidic mixing have been published (Langmuir. 2012. 28:3633-40; Belliveau, N.M. et al., Microfluidic synthesis of highly potent limit-size lipid nanoparticles for in vivo delivery of siRNA. Molecular Therapy-Nucleic Acids. 2012. 1:e37; Chen, D. et al., Rapid discovery of potent siRNA-containing lipid nanoparticles enabled by controlled microfluidic formulation. J Am Chem Soc. 2012. 134(16):6948-51 ).

[0230] In some embodiments, methods of LNP generation comprising SHM, further comprise the mixing of at least two input streams wherein mixing occurs by microstructure-induccd chaotic advection (MICA). According to this method, fluid streams flow through channels present in a herringbone pattern causing rotational flow and folding the fluids around each other. This method may also comprise a surface for fluid mixing wherein the surface changes orientations during fluid cycling. Methods of generating LNPs using SHM include those disclosed in U.S. Application Publication Nos. 2004 / 0262223 and 2012 / 0276209 .

[0231] In one embodiment, the lipid nanoparticles may be formulated using a micromixer such as, but not limited to, a Slit Interdigital Microstructured Mixer (SIMM-V2) or a Standard Slit Interdigital Micro Mixer (SSIMM) or Caterpillar (CPMM) or Impinging-jet (IJMM)from the Institut für Mikrotechnik Mainz GmbH, Mainz Germany).

[0232] In one embodiment, the lipid nanoparticles are created using microfluidic technology (see Whitesides, George M. The Origins and the Future of Microfluidics. Nature, 2006 442: 368-373; and Abraham et al. Chaotic Mixer for Microchannels. Science, 2002 295: 647-651). As a non-limiting example, controlled microfluidic formulation includes a passive method for mixing streams of steady pressure-driven flows in micro channels at a low Reynolds number (See e.g., Abraham ct al. Chaotic Mixer for Microchannels. Science, 2002 295: 647651).

[0233] In one embodiment, the mRNA of the present invention may be formulated in lipid nanoparticles created using a micromixer chip such as, but not limited to, those from Harvard Apparatus (Holliston, MA) or Dolomite Microfluidics (Royston, UK). A micromixcr chip can be used for rapid mixing of two or more fluid streams with a split and recombine mechanism.

[0234] In one embodiment, the lipid nanoparticles may have a diameter from about 10 to about 100 nm such as, but not limited to, about 10 to about 20 nm, about 10 to about 30 nm, about 10 to about 40 nm, about 10 to about 50 nm, about 10 to about 60 nm, about 10 to about 70 nm, about 10 to about 80 nm, about 10 to about 90 nm, about 20 to about 30 nm, about 20 to about 40 nm, about 20 to about 50 nm, about 20 to about 60 nm, about 20 to about 70 nm, about 20 to about 80 nm, about 20 to about 90 nm, about 20 to about 100 nm, about 30 to about 40 nm, about 30 to about 50 nm, about 30 to about 60 nm, about 30 to about 70 nm, about 30 to about 80 nm, about 30 to about 90 nm, about 30 to about 100 nm, about 40 to about 50 nm, about 40 to about 60 nm, about 40 to about 70 nm, about 40 to about 80 nm, about 40 to about 90 nm, about 40 to about 100 nm, about 50 to about 60 nm, about 50 to about 70 nm about 50 to about 80 nm, about 50 to about 90 nm, about 50 to about 100 nm, about 60 to about 70 nm, about 60 to about 80 nm, about 60 to about 90 nm, about 60 to about 100 nm, about 70 to about 80 nm, about 70 to about 90 nm, about 70 to about 100 nm, about 80 to about 90 nm, about 80 to about 100 nm and / or about 90 to about 100 nm. In one embodiment, the lipid nanoparticles may have a diameter from about 10 to 500 nm. In one embodiment, the lipid nanoparticle may have a diameter greater than 100 nm, greater than 150 nm, greater than 200 nm, greater than 250 nm, greater than 300 nm, greater than 350 nm, greater than 400 nm, greater than 450 nm, greater than 500 nm, greater than 550 nm, greater than 600 nm, greater than 650 nm, greater than 700 nm, greater than 750 nm, greater than 800 nm, greater than 850 nm, greater than 900 nm, greater than 950 nm or greater than 1000 nm. Each possibility represents a separate embodiment of the present invention.

[0235] In some embodiments, the lipid nanoparticle has a polydiversity value of less than 0.4. In some embodiments, the lipid nanoparticle has a net neutral charge at a neutral pH. In some embodiments, the lipid nanoparticle has a mean diameter of 50-200nm.Lipids

[0236] As generally defined herein, the term "lipid" refers to a small molecule that has hydrophobic or amphiphilic properties. Lipids may be naturally occurring or synthetic. Examples of classes of lipids include, but are not limited to, fats, waxes, sterol-containing metabolites, vitamins, fatty acids, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides, and prenol lipids. In some instances, the amphiphilic properties of some lipids leads them to form liposomes, vesicles, or membranes in aqueous media.Cationic / ionizable lipids

[0237] A nanoparticle composition may include one or more cationic and / or ionizable lipids (e.g., lipids that may have a positive or partial positive charge at physiological pH). Cationic and / or ionizable lipids may be selected from the non-limiting group consisting of 3-(didodecylamino)-N1,N1,4-tridodecyl-1-piperazineethanamine (KL10), N1-[2-(didodecylamino)ethyl] N1,N4,N4-tridodecyl-1,4-piperazinediethanamine (KL22). 14.25-diuidecyl-15,18,21,24-tctraaza-octatriacontane (KL25), 1.2-dilinoleyloxy-N,N-dimethylaminopropane (DLin-DMA), 2,2-dilinoleyl-4-dimethylaminomethyl-[1,3]-dioxolane (DLin-K-DMA), heptatriaconta-6,9,28,31-tetraen-19-yl-4-(dimethylamino)butanoate (DLin-MC3-DMA), 2,2-dilinoleyl-4-(2 dimethylaminoethyl)-[1,3]-dioxolane (DLin-KC2-DMA), 1,2-dioleyloxy-N,N-dimethylaminopropane (DODMA), 2-({8 [(3β)-cholest-5-en-3-yloxy]octyl}oxy) N,N dimethyl-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]propan-1-amine (Octyl-CLinDMA). (2R)-2-((B-[(3β)-cholest-5-en-3-yloxy]octyl}oxy)-N,N-dimethyl-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]propan-1-amine (Octyl-CLinDMA (2R)), and (2S) 2-({8-[(3β)-cholest-5-en-3-yloxy]octyl}oxy)-N,N-dimethyl-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]propan-1-amine (Octyl-CLinDMA (2S)). In addition to these, a cationic lipid may also be a lipid including a cyclic amine group. Each possibility represents a separate embodiment of the present invention. Each possibility represents a separate embodiment of the present invention.

[0238] In one embodiment, the cationic lipid may be selected from, but not limited to, a cationic lipid described in International Publication Nos. WO2012040184, WO2011153120, WO2011149733, WO2011090965, WO2011043913, WO2011022460, WO2012061259, WO2012054365, WO2012044638, WO2010080724, WO201021865, WO2008103276 WO2013086373 and WO2013086354, US Patent Nos. 7,893,302, 7,404,969, 8,283,333, and 8,466,122 and US Patent Publication No. US20100036115, US20120202871, US20130064894, US20130129785, US20130150625, US20130178541 and S20130225836.

[0239] In another embodiment, the cationic lipid may be selected from, but not limited to, formula A described in International Publication Nos. WO2012040184, WO2011153120, WO2011149733, WO2011090965, WO2011043913, WO2011022460, WO2012061259, WO2012054365, WO2012044638 and WO2013116126 or US Patent Publication No. US20130178541 and US20130225836. In yet another embodiment, the cationic lipid may be selected from, but not limited to, formula CLI-CLXXIX of International Publication No. WO2008103276, formula CLI-CLXXIX of US Patent No. 7,893,302, formula CLI-CLXXXXII of US Patent No. 7,404,969 and formula I-VI of US Patent Publication No. US20100036115, formula I of US Patent Publication No US20130123338.

[0240] As a non-limiting example, the cationic lipid may be selected from (20Z,23Z)-N,N-dimethytnonacosa-20,23-dien-10-amine, (17Z,20Z)-N,N-dimemylhexacosa-17,20-dien-9-amine, (1Z,19Z)-N5N-dimethylpentacosa-16, 19-dien-8-amine, (13Z,16Z)-N,N-dimethyldocosa-13, 16-dien-5-amine, (12Z,15Z)-N,N dimethylhenicosa-12,15- dien-4-amine, (14Z,17Z)-N,N-dimethyltricosa-14,17-dien-6-amine, (15Z,18Z)-N,N-dimethyltetracosa-15,18-dien-7-amine, (18Z,21Z)-N,N-dimethylheptacosa-18,21-dien-10-amine, (15Z,18Z)-N,N-dimethyltetracosa-15,18-dien-5-amine, (14Z,17Z)-N,N-dimethyltricosa-14, 17-dien-4-amine, (19Z,22Z)-N,N-dimeihyloctacosa-19,22-dien-9-amine, (18Z,21 Z)-N,N-dimethylheptacosa- 18,21 -dien-8 -amine, (17Z,20Z)-N,N-dimethylhexacosa- 17,20-dien-7-amine, (16Z,19Z)-N,N-dimethylpentacosa-16,19-dien-6-amine, (22Z,25Z)-N,N-dimethylhentriaconta-22,25-dien-10-amine, (21 Z ,24Z)-N,N-dimethyltriaconta-21,24-dien-9-amine, (18Z)-N,N-dimetylheptacos-18-en-10-amine, (17Z)-N,N-dimethylhexacos-17-en-9-amine, (19Z,22Z)-N,N-dimethyloctacosa-19,22-dien-7-amine, N,N-dimethylheptacosan-10-amine, (20Z,23Z)-N-ethyl-N-methylnonacosa-20,23-dien-10-amine, 1-[(11Z,14Z)-1-nonylicosa-11,14-dien-1-yl] pyrrolidine, (20Z)-N,N-dimethylheptacos-20-en-10-amine, (15Z)-N,N-dimethyl eptacos-15-en-10-amine, (14Z)-N,N-dimethylnonacos-14-en-10-amine, (17Z)-N,N-dimethylnonacos-17-en-10-amine, (24Z)-N,N-dimethyltritriacont-24-en-10-amine, (20Z)-N,N-dimethylnonacos-20-en-1 0-amine, (22Z)-N,N-dimethylhentriacont-22-en-10-amine, (16Z)-N,N-dimethylpentacos-16-en-8-amine, (12Z,15Z)-N,N-dimethyl-2-nonylhenicosa-12,15-dien-1-amine, (13Z,16Z)-N,N-dimethyl-3-nonyldocosa-13,16-dien-1-amine, N,N-dimethyl-1-[(1S,2R)-2-octylcyclopropyl] eptadecan-8-amine, 1-[(1S,2R)-2-hexylcyclopropyl]-N,N- dimethylnonadecan-10-amine, N,N-dimethyl-1-[(1S ,2R)-2-octylcyclopropyl]nonadecan-10-amine, N,N-dimethyl-21-[(1S,2R)-2-octylcyclopropyl]henicosan-10-amine,N,N-dimethy]-1-[(1S,2S)-2-{[(1R,2R)-2-pentylcyclopropyl)methyl}cyclopropyl]nonadecan-10-amine,N,N-dimethyl-1-[(1S,2R)-2-octylcyclopropyl]hexadecan-8-amine, N,N-dimethyl-[(1R,2S)-2 undecylcyclopropyl]tetradecan-5-amine, N,N-dimethyl-3-{7-[(1S,2R)-2-octylcyclopropyl]heplyl} dodecan-1-amine, 1-[(1R)2S)-2-hepty lcyclopropyl]-N,N-dimethyloctadecan-9-amine, 1-[(1S,2R)-2-decylcyclopropyl]-N,N-dimethylpentadecan-6-amine, N,N-dimethy)-1-[(1S,2R)-2-octylcyclopropyl]pentadecan-8-amine, R-N,N-dimcthy(-1-[(9Z, 12Z)-octadeca-9,12- dien-1-yloxy]-3-(octyloxy)propan-2-am ine, S-N,N-dimethyl-1-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]-3-(octyloxy)propan-2-amine, 1-{2-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]-1-[(octyloxy)methyl]ethyl}pyrrolidine, (2S)-N,N-dimethyl-1-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]-3-[(5Z)-oct-5-en-1-yloxy]propan-2-amine, 1-{2-[(9Z,12Z)-octadeca-9, 12-dien-1-yloxy]-1-[(octyloxy)methyl]ethyl}azetidine, (2S)-1-(hexyloxy)-N,N-dimethyl-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]propan-2-amine, (2S)-1-(heptyloxy)-N,N-dimethyl-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]propan-2-amine, N,N-dimethyl-1-(nonyloxy)-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]propan-2-amine, N,N-dimethyl-1-[(9Z)-octadec-9-en-1-ytoxy]-3-(octytoxy)propan-2-amine; (2S)-N,N-dimethyl-1-[(6Z,9Z,12Z)-octadeca-6,9,12-trien-1-yloxy]-3-(octyloxy)propan-2-amine, (2S)-1 - [(11Z,14Z)-icosa-11,14-dien-1-yloxy]-N,N-dimethyl-3-(pentyloxy)propan-2-amine, (2S)-1-(hexyloxy)-3-[(11Z,14Z)-icosa-11,14-dien-1-yloxy]-N,N-dimethylpropan-2-amine, 1-[(11Z,14Z)-icosa-11,14-dien-1-yloxy]-N,N-dimethyl-3-(octyloxy)propan-2-amine, 1-[(13Z,16Z)-docosa-13,16-dien-1-yloxy]-N,N-dimethyl-3-(octyloxy)propan-2-amine, (2S)-1 - [(13Z,16Z)-docosa-13,16-dien-1-yloxy]-3-(hexyloxy)-N,N-dimethylpropan-2-amine, (2S)-1-[(13Z)-docos-13-en-1-yloxy]-3-(hexyloxy)-N,N-dimethylpropan-2-amine, 1-[(13Z)-docos-13-en-1-yloxy]-N,N-dimethyl-3-(octyloxy)propan-2-amine, 1-[(9Z)-hexadec-9-en-1-yloxy]-N,N-dimethyl-3-(octyloxy)propan-2-amine, (2R)-N,N-dimethyl-H(1-metoyloctyl)oxy]-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]propon-2-amine, (2R)-1-[(3,7- dimethyloctyl)oxy]-N,N-dimethyl-3-[(9Z,12Z)-octadeca-9,12-dien-1-yloxy]propan-2-amine, N,N-dimethyl-1-(octyloxy)-3-({8-[(1S,2S)-2-{[(1R,2R)-2-pentylcyclopropyl]methyl} cyclopropyl]octyl} oxy)propan-2-am ine, N,N-dimethyl-1-{[8-(2-oclylcyclopropyl)octy)]oxy}-3-(octytoxy)propan-2-amine and (11E,20Z,23Z)- N,N-dimethylnonacosa-11,20,2-trien-10-aminc or a pharmaceutically acceptable salt or stereoisomer thereof. Each possibility represents a separate embodiment of the present invention.

[0241] Additional examples of cationic lipids include the following: and

[0242] In one embodiment, the lipid may be a cleavable lipid such as those described in International Publication No. WO2012170889. In another embodiment, the lipid may be a cationic lipid such as, but not limited to, Formula (1) of U.S. Patent Application No. US20130064894. In one embodiment, the cationic lipid may be synthesized by methods known in the art and / or as described in International Publication Nos. WO2013086354. In another embodiment, the cationic lipid may be a trialkyl cationic lipid. Non-limiting examples of trialkyl cationic lipids and methods of making and using the trialkyl cationic lipids are described in International Patent Publication No. WO2013126803.

[0243] In some embodiments, additional lipids may comprise a compound of Formula (X): or a salt or isomer thereof, wherein: R 1 is selected from the group consisting of C 5-30 alkyl, C 5-20 alkenyl, -R ∗< YR'', -YR'', and -R''M'R'; R 2 and R 3 are independently selected from the group consisting of H, C 1-14 alkyl, C 2-14 alkenyl, -R ∗< YR'', -YR", and -R ∗< OR'', or R 2 and R 3 , together with the atom to which they are attached, form a heterocycle or carbocycle; R 4 is selected from the group consisting of a C 3-6 carbocycle, -(CH 2 ) n Q, -(CH 2 ) n CHQR, -CHQR, -CQ(R) 2 , and unsubstituted C 1-6 alkyl, where Q is selected from a carbocycle, heterocycle, -OR, -O(CH 2 ) n N(R) 2 , -C(O)OR, -OC(O)R, -CX 3 , -CX 2 H, -CXH 2 , -CN, -N(R) 2 , -C(O)N(R) 2 , -N(R)C(O)R, -N(R)S(O) 2 R, -N(R)C(O)N(R) 2 , -N(R)C(S)N(R) 2 , -N(R)R 8 , -O(CH 2 ) n OR, -N(R)C(=NR 9 )N(R) 2 , -N(R)C(=CHR 9 )N(R) 2 , -OC(O)N(R) 2 , -N(R)C(O)OR, -N(OR)C(O)R, -N(OR)S(O) 2 R, -N(OR)C(O)OR, -N(OR)C(O)N(R) 2 , -N(OR)C(S)N(R) 2 , -N(OR)C(=NR 9 )N(R) 2 , -N(OR)C(=CHR 9 )N(R) 2 , -C(=NR 9 )N(R) 2 , -C(=NR 9 )R, -C(O)N(R)OR, and -C(R)N(R) 2 C(O)OR, and each n is independently selected from 1, 2, 3, 4, and 5; each R 5 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R 6 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; M and M' are independently selected from -C(O)O-, -OC(O)-, -C(O)N(R')-, -N(R')C(O)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(O)(OR')O-, -S(O) 2 -, -S-S-, an aryl group, and a heteroaryl group; R 7 is selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; R 8 is selected from the group consisting of C 3-6 carbocycle and heterocycle; R 9 is selected from the group consisting of H, CN, NO 2 , C 1-6 alkyl, -OR, -S(O) 2 R, -S(O) 2 N(R) 2 , C 2-6 alkenyl, C 3-6 carbocycle and heterocycle; each R is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R' Is Independently selected trom the group consisting of C 1-18 alkyl, C 2-18 alkenyl, -R ∗< YR'', -YR'', and H; each R'' is independently selected from the group consisting of C 3-14 alkyl and C 3-14 alkenyl; each R ∗< is independently selected from the group consisting of C 1-12 alkyl and C 2-12 alkenyl; each Y is independently a C 3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13.

[0244] In some embodiments, a subset of compounds of Formula (X) includes those in which when R 4 is -(CH 2 ) n Q, -(CH 2 ) n CHQR, -CHQR, or -CQ(R) 2 , then (i) Q is not -N(R) 2 when n is 1, 2, 3, 4 or 5, or (ii) Q is not 5, 6, or 7-membered heterocycloalkyl when n is 1 or 2.

[0245] In some embodiments, another subset of compounds of Formula (X) includes those in which R 1 is selected from the group consisting of C 5-30 alkyl, C 5-20 alkenyl, -R ∗< YR'', -YR'', and -R''M'R'; R 2 and R 3 are independently selected from the group consisting of H, C 1-14 alkyl, C 2-14 alkenyl, -R ∗< YR'', -YR'', and -R ∗< OR'', or R 2 and R 3 , together with the atom to which they arc attached, form a heterocycle or carbocycle; R 4 is selected from the group consisting of a C 3-6 carbocycle, -(CH 2 ) n Q, -(CH 2 ) n CHQR, -CHQR, -CQ(R) 2 , and unsubstituted C 1-6 alkyl, where Q is selected from a C 3-6 carbocycle, a 5- to 14-membered heteroaryl having one or more heteroatoms selected from N, O, and S, - OR, -O(CH 2 ) n N(R) 2 , -C(O)OR, -OC(O)R, -CX 3 , -CX 2 H, -CXH 2 , -CN, -C(O)N(R) 2 , -N(R)C(O)R, -N(R)S(O) 2 R, -N(R)C(O)N(R) 2 , -N(R)C(S)N(R) 2 , -CRN(R) 2 C(O)OR, -N(R)R 8 , -O(CH 2 ) n OR, -N(R)C(-NR 9 )N(R) 2 , -N(R)C(=CHR 9 )N(R) 2 , -OC(O)N(R) 2 , -N(R)C(O)OR, -N(OR)C(O)R, -N(OR)S(O) 2 R, -N(OR)C(O)OR, -N(OR)C(O)N(R) 2 , -N(OR)C(S)N(R) 2 , -N(OR)C(=NR 9 )N(R) 2 , -N(OR)C(=CHR 9 )N(R) 2 , -C(=NR 9 )N(R) 2 , -C(=NR 9 )R, -C(O)N(R)OR, and a 5- to 14-membered heterocycloalkyl having one or more heteroatoms selected from N, O, and S which is substituted with one or more substituents selected from oxo (=O), OH, amino, mono- or di-alkylamino, and C 1-3 alkyl, and each n is independently selected from 1, 2, 3, 4, and 5; each R 5 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R 6 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; M and M' are independently selected from -C(O)O-, -OC(O)-, -C(O)N(R')-, -N(R')C(O)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(O)(OR')O-, -S(O) 2 -, -S-S-, an aryl group, and a heteroaryl group; R 7 is selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; R 8 is selected from the group consisting of C 3-6 carbocycle and heterocycle; R 9 is selected from the group consisting of H, CN, NO 2 , C 1-6 alkyl, -OR, -S(O) 2 R, -S(O) 2 N(R) 2 , C 2-6 alkenyl. C 3-6 carbocycle and heterocycle; each R is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R' is independently selected from the group consisting of C 1-18 alkyl, C 2-18 alkenyl, -R ∗< YR'', -YR'', and H; each R'' is independently selected from the group consisting of C 3-14 alkyl and C 3-14 alkenyl; each R ∗< is independently selected from the group consisting of C 1-12 alkyl and C 2-12 alkenyl; each Y is independently a C 3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

[0246] In some embodiments, another subset of compounds of Formula (X) includes those in which R 1 is selected from the group consisting of C 5-30 alkyl, C 5-20 alkenyl, -R ∗< YR'', -YR'', and -R''M'R'; R 2 and R 3 are independently selected from the group consisting of H, C 1-14 alkyl, C 2-14 alkenyl, -R ∗< YR'', -YR'', and -R ∗< OR'', or R 2 and R 3 , together with the atom to which they are attached, form a heterocycle or carbocycle; R 4 is selected from the group consisting of a C 3-6 carbocycle, -(CH 2 ) n Q, -(CH 2 ) n CHQR, -CHQR, -CQ(R) 2 , and unsubstituted C 1-6 alkyl, where Q is selected from a C 3-6 carbocycle, a 5- to 14-membered heterocycle having one or more heteroatoms selected from N, O, and S, - OR, -O(CH 2 ) n N(R) 2 , -C(O)OR, -OC(O)R, -CX 3 , -CX 2 H, -CXH 2 , -CN, -C(O)N(R) 2 , -N(R)C(O)R, -N(R)S(O) 2 R, -N(R)C(O)N(R) 2 , -N(R)C(S)N(R) 2 , -CRN(R) 2 C(O)OR, -N(R)R 8 , -O(CH 2 ) n OR, -N(R)C(=NR 9 )N(R) 2 , -N(R)C(=CHR 9 )N(R) 2 , -OC(O)N(R) 2 , -N(R)C(O)OR, -N(OR)C(O)R, -N(OR)S(O) 2 R, -N(OR)C(O)OR, -N(OR)C(O)N(R) 2 , -N(OR)C(S)N(R) 2 , -N(OR)C(=NR 9 )N(R) 2 , -N(OR)C(=CHR 9 )N(R) 2 , -C(=NR 9 )R, -C(O)N(R)OR, and -C(=NR 9 )N(R) 2 , and each n is independently selected from 1, 2, 3, 4, and 5; and when Q is a 5- to 14-membered heterocycle and (i) R 4 is -(CH 2 ) n Q in which n is 1 or 2, or (ii) R 4 is -(CH 2 ) n CHQR in which n is 1, or (iii) R 4 is -CHQR, and -CQ(R) 2 , then Q is either a 5- to 14-membered heteroaryl or 8- to 14-membered heterocycloalkyl; each R 5 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R 6 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; M and M' are independently selected from -C(O)O-, -OC(O)-, -C(O)N(R')-, -N(R')C(O)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(O)(OR')O-, -S(O) 2 -, -S-S-, an aryl group, and a heteroaryl group; R 7 is selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; R 8 is selected from the group consisting of C 3-6 carbocycle and heterocycle; R 9 is selected from the group consisting of H, CN, NO 2 , C 1-6 alkyl, -OR, -S(O) 2 R, -S(O) 2 N(R) 2 , C 2-6 alkenyl, C 3-6 carbocycle and heterocycle; each R is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R' is independently selected from the group consisting of C 1-18 alkyl, C 2-18 alkenyl, -R ∗< YR'', -YR'', and H; each R'' is independently selected from the group consisting of C 3-14 alkyl and C 3-14 alkenyl; each R ∗< is independently selected from the group consisting of C 1-12 alkyl and C 2-12 alkenyl; each Y is independently a C 3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or Isomers thereof.

[0247] In some embodiments, another subset of compounds of Formula (X) includes those in which R 1 is selected from the group consisting of C 5-30 alkyl, C 5-20 alkenyl, -R ∗< YR'', -YR'', and -R''M'R'; R 2 and R 3 are independently selected from the group consisting of H, C 1-14 alkyl, C 2-14 alkenyl, -R ∗< YR'', -YR'', and -R ∗< OR'', or R 2 and R 3 , together with the atom to which they are attached, form a heterocycle or carbocycle; R 4 is selected from the group consisting of a C 3-6 carbocycle, -(CH 2 ) n Q, -(CH 2 ) n CHQR, -CHQR, -CQ(R) 2 , and unsubstituted C 1-6 alkyl, where Q is selected from a C 3-6 carbocycle, a 5- to 14-membered heteroaryl having one or more heteroatoms selected from N, O, and S, - OR, -O(CH 2 ) n N(R) 2 , -C(O)OR, -OC(O)R, -CX 3 , -CX 2 H, -CXH 2 , -CN, -C(O)N(R) 2 , -N(R)C(O)R, -N(R)S(O) 2 R, -N(R)C(O)N(R) 2 , -N(R)C(S)N(R) 2 , -CRN(R) 2 C(O)OR, -N(R)R 8 , -O(CH 2 ) n OR, -N(R)C(=NR 9 )N(R) 2 , -N(R)C(=CHR 9 )N(R) 2 , -OC(O)N(R) 2 , -N(R)C(O)OR, -N(OR)C(O)R, -N(OR)S(O) 2 R, -N(OR)C(O)OR, -N(OR)C(O)N(R) 2 , -N(OR)C(S)N(R) 2 , -N(OR)C(=NR 9 )N(R) 2 , -N(OR)C(=CHR 9 )N(R) 2 , -C(=NR 9 )R, -C(O)N(R)OR, and -C(=NR 9 )N(R) 2 , and each n is independently selected from 1, 2, 3, 4, and 5; each R 5 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R 6 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; M and M' are independently selected from -C(O)O-, -OC(O)-, -C(O)N(R')-, -N(R')C(O)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(O)(OR')O-, -S(O) 2 -, -S-S-, an aryl group, and a heteroaryl group; R 7 is selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; R 8 is selected from the group consisting of C 3-6 carbocycle and heterocycle; R 9 is selected from the group consisting of H, CN, NO 2 , C 1-6 alkyl, -OR, -S(O) 2 R, -S(O) 3 N(R) 2 , C 2-6 alkenyl, C 3-6 carbocycle and heterocycle; each R is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R' is independently selected from the group consisting of C 1-18 alkyl, C 2-18 alkenyl, -R ∗< YR'', -YR'', and H; each R'' is independently selected from the group consisting of C 3-14 alkyl and C 3-14 alkenyl; each R ∗< is independently selected from the group consisting of C 1-12 alkyl and C 2-12 alkenyl; each Y is independently a C 3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

[0248] In some embodiments, another subset of compounds of Formula (X) includes those in which R 1 is selected from the group consisting of C 5-30 alkyl, C 5-20 alkenyl, -R ∗< YR'', -YR'', and -R''M'R'; R 2 and R 3 are independently selected from the group consisting of H, C 2-14 alkyl, C 2-14 alkenyl, -R ∗< YR'', -YR'', and -R ∗< OR'', or R 2 and R 3 , together with the atom to which they are attached, form a heterocycle or carbocycle; R 4 is -(CH 2 ) n Q or -(CH 2 ) n CHQR, where Q is -N(R) 2 , and n is selected from 3, 4, and 5; each R 5 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R 6 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; M and M' are independently selected from -C(O)O-, -OC(O)-, -C(O)N(R')-, -N(R')C(O)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(O)(OR')O-, -S(O) 2 -, -S-S-, an aryl group, and a heteroaryl group; R 7 is selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R' is independently selected from the group consisting of C 1-18 alkyl, C 2-18 alkenyl, -R ∗< YR'', -YR'', and H; each R'' is independently selected from the group consisting of C 3-14 alkyl and C 3-14 alkenyl; each R ∗< is independently selected from the group consisting of C 1-12 alkyl and C 1-12 alkenyl; each Y is independently a C 3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

[0249] In some embodiments, another subset of compounds of Formula (X) includes those in which R 1 is selected from the group consisting of C 5-30 alkyl, C 5-20 alkenyl, -R ∗< YR'', -YR'', and -R''M'R'; R 2 and R 3 are independently selected from the group consisting of C 1-14 alkyl, C 2-14 alkenyl, -R ∗< YR'', -YR'', and -R ∗< OR'', or R 2 and R 3 , together with the atom to which they are attached, form a heterocycle or carbocycle; R 4 is selected from the group consisting of -(CH 2 ) n Q, -(CH 2 ) n CHQR, -CHQR, and -CQ(R) 2 , where Q is -N(R) 2 , and n is selected from 1, 2, 3, 4, and 5; each R 5 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R 6 is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; M and M' are independently selected from -C(O)O-, -OC(O)-, -C(O)N(R')-, -N(R')C(O)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(O)(OR')O-, -S(O) 2 -, -S-S-, an aryl group, and a heteroaryl group; R 7 is selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R is independently selected from the group consisting of C 1-3 alkyl, C 2-3 alkenyl, and H; each R' is independently selected from the group consisting of C 1-18 alkyl, C 2-18 alkenyl, -R ∗< YR'', -YR'', and H; each R" is independently selected from the group consisting of C 3-14 alkyl and C 3-14 alkenyl; each R ∗< is independently selected from the group consisting of C 1-12 alkyl and C 1-12 alkenyl; each Y is independently a C 3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

[0250] In some embodiments, a subset of compounds of Formula (X) includes those of Formula (XA): or a salt or isomer thereof, wherein | is selected from 1, 2, 3, 4, and 5; m is selected from 5, 6, 7, 8, and 9; M 1 is a bond or M'; R 4 is unsubstituted C 1-3 alkyl, or -(CH 2 ) n Q, in which Q is OH, -NHC(S)N(R) 2 , -NHC(O)N(R) 2 , -N(R)C(O)R, -N(R)S(O) 2 R, -N(R)R 8 , -NHC(=NR 9 )N(R) 2 , -NHC(=CHR 9 )N(R)2, -OC(O)N(R) 2 , -N(R)C(O)OR, heteroaryl or heterocycloalkyl; M and M' are independently selected from -C(O)O-, -OC(O)-, -C(O)N(R')-, -P(O)(OR')O-, -S-S-, an aryl group, and a heteroaryl group; and R 2 and R 3 are independently selected from the group consisting of H, C 1-14 alkyl, and C 2-14 alkenyl.

[0251] In some embodiments, a subset of compounds of Formula (X) includes those of Formula (XI): (II) or a salt or isomer thereof, wherein | is selected from 1, 2, 3, 4, and 5; M 1 is a bond or M'; R 4 is unsubstituted C 1-3 alkyl, or -(CH 2 ) n Q, in which n is 2, 3, or 4, and Q is OH, -NHC(S)N(R) 2 , -NHC(O)N(R) 2 , -N(R)C(O)R, -N(R)S(O) 2 R, -N(R)R 8 , -NHC(=NR 9 )N(R) 2 , -NHC(=CHR 9 )N(R) 2 , -OC(O)N(R) 2 , -N(R)C(O)OR, heteroaryl or heterocycloalkyl; M and M' are independently selected from -C(O)O-, -OC(O)-, -C(O)N(R')-, -P(O)(OR')O-, -S-S-, an aryl group, and a heteroaryl group; and R 2 and R 3 are independently selected from the group consisting of H, C 1-14 alkyl, and C 2-14 alkenyl.

[0252] In some embodiments, a subset of compounds of Formula (X) includes those of Formula (XIa), (XIb), (XIc), or (XIe): or or a salt or isomer thereof, wherein R 4 is as described herein.

[0253] In some embodiments, a subset of compounds of Formula (X) includes those of Formula (XId): or a salt or isomer thereof, wherein n is 2, 3, or 4; and m, R', R'', and R 2 through R 6 are as described herein. For example, each of R 2 and R 3 may be independently selected from the group consisting of C 5-14 alkyl and C 5-14 alkenyl.

[0254] In some embodiments, a subset of compounds of Formula (X) includes those of Formula (XIa), (XIb), (XIc), or (XIe): or a salt or isomer thereof, wherein R 4 is as described herein.

[0255] In some embodiments, a subset of compounds of Formula (X) includes those of Formula (XId): or a salt or isomer thereof, wherein n is 2, 3, or 4; and m, R', R'', and R 2 through R 6 are as described herein. For example, each of R 2 and R 3 may be independently selected from the group consisting of C 5-14 alkyl and C 5-14 alkenyl.

[0256] In some embodiments, the compound of Formula (X) is selected from the group consisting of:

[0257] In further embodiments, the compound of Formula (X) is selected from the group consisting of:

[0258] In some embodiments, the compound of Formula (X) is selected from the group consisting of: isomers thereof,

[0259] In some embodiments, a nanoparticle comprises the following compound: and isomers thereof.

[0260] In some embodiments, the disclosure features a nanoparticle composition including a lipid component comprising a compound as described herein (e.g., a compound according to Formula (X), (XA), (XI), (XIa), (XIb), (XIc), (XId) or (XIe)).Non-cationic lipids, including non-cationic helper lipids

[0261] The lipid component of the nanoparticle may include any neutral and / or non-cationic lipid (e.g., lipids that are neutral or non-cationic lipid at physiological pH). Non-cationic lipid lipids may include, but are not limited to, fatty acids, glycerolipids, and prenol lipids. In certain embodiments, the non-cationic lipid is a fatty acid. The fatty acid may be saturated or unsaturated. Examples of unsaturated fatty acids include, but are not limited to, myristoleic acid, palmitoleic acid sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, alpha-linoelaidic acid arachidonic acid, eicosapentaenoic acid, erucic acid, docosahexanoic acid, or any cis / trans double-bond isomers thereof. In certain embodiments, the lipid is oleic acid. In certain embodiments, the lipid is an isomer of oleic acid (e.g., the double bond is in a different location along the aliphatic chain relative to oleic acid). In certain embodiments, the lipid is an analog of oleic acid (e.g., the aliphatic chain is 1-10 carbons longer or 1-10 carbons shorter than the aliphatic chain of oleic acid). Examples of saturated fatty acids include, but are not limited to, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, and cerotic acid. In certain embodiments, the non-cationic lipid is a glycine derivative of a fatly acid (e.g., N-palitoylglycine or N-oleoglycine) In certain embodiments, the non-cationic lipid is a glycerolipid (e.g., monoglyceride, diglyceride, triglyceride). In certain embodiments, the non-cationic lipid is a monoglyceride. In certain embodiments, the non-cationic lipid is a diglyceride. In certain embodiments, the non-cationic lipid is a triglyceride. In certain embodiments, the non-cationic lipid comprises a sugar moeity (e.g., saccharide, disaccharide, polysaccharide). Examples of non-cationic lipids include, but are not limited to, the following:

[0262] Examples of non-cationic lipids comprising sugars include, but arc not limited to the following: and Zwitterionic Non-Cationic Lipids

[0263] In certain embodiments, non-cationic lipids useful in the present invention are DSPC analogs wherein the phosphocholine moiety is replaced by a different zwitterionic group.

[0264] DSPC has the following structure:

[0265] The replacement with a different zwitterionic group is depicted in FIG. 73.

[0266] In certain embodiments, the different zwitterionic group is not a phosphocholinc group. In certain embodiments, a non-cationic lipid useful in the present invention is a compound of Formula (II ). Provided herein are compounds of Formula (II ): or a salts thereof, wherein: Z is a zwitterionic moiety, wherein the zwitterionic moiety is not of the formula: m is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10;

[0267] A is of the formula: each instance of L 2< is independently a bond or optionally substituted C 1-6 alkylene, wherein one methylene unit of the optionally substituted C 1-6 alkylene is optionally replaced with -O-, -N(R N< )-, -S-, -C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -C(O)O-, -OC(O)-, - OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, or -NR N< C(O)N(R N< )-; each instance of R 2 is independently optionally substituted C 1-30 alkyl, optionally substituted C 1-30 alkenyl, or optionally substituted C 1-30 alkynyl; optionally wherein one or more methylene units of R 2 are independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-, - NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(O)N(R N< )-, - NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-, -NR N< C(=NR N< )-, - NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-, - OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-, - S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, -N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, -OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group; Ring B is optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, or optionally substituted heteroaryl; and p is 1 or 2.

[0268] In certain embodiments, Z is an amino acid or a derivative thereof. In certain embodiments, Z is of one of the following formulae: wherein R O< is hydrogen, optionally substituted alkyl or an oxygen protecting group. In certain embodiments, a compound of Formula (II ) is of one of the following formulae: or a salt thereof.

[0269] In certain embodiments, a compound of Formula (II ) is of one of the following formulae: or a salt thereof.

[0270] For example, in certain embodiments, a compound of Formula (II) is one of the following: or salts thereof.Oleic Acid Analogs

[0271] As described herein, non-cationic lipids useful in the present invention include analogs of oleic acid. As described herein, an oleic acid analog can comprise a modified oleic acid tail, a modified carboxylic acid moiety, or both. In certain embodiments, an analog of oleic acid is a compound of Formula (IV ). Provided herein are compounds of Formula (IV ): or a salt thereof, wherein: R 4< is optionally substituted, C 10-40 alkyl; optionally substituted, C 10-40 alkenyl; optionally substituted, C 10-40 alkynyl; wherein at least one methylene group of R 4< is independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, - OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, - C(=NR N< )N(R N< )-, -NR N< C(=NR N< )-, -NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, - NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-, -OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, - S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-, -S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, - N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, - OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; and each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group.

[0272] In certain embodiments, the compound of Formula (IV ) is one of the following: or salts thereof.

[0273] In certain embodiments, an oleic acid analog is a compound wherein the carboxylic acid moiety of oleic acid replaced by a different group. In certain embodiments, an oleic acid analog useful in the present invention is one of the following: or salts thereof.

[0274] In certain embodiments, an oleic acid analog useful in the present invention is: PEGylated lipids

[0275] The lipid component of a nanoparticle composition may include one or more PEG or PEG-modified lipids. Such species may be alternately referred to as PEGylated lipids. A PEG lipid is a lipid modified with polyethylene glycol. A PEG lipid may be selected from the non-limiting group consisting of PEG-modified phosphatidylethanolamines, PEG-modified phosphatidic acids, PEG-modified ceramides, PEG-modified dialkylamines, PEG-modified diacylglycerols, PEG-modified dialkylglycerols, and mixtures thereof. For example, a PEG lipid may be PEG-c-DOMG, PEG-DMG, PEG-DLPE, PEG-DMPE, PEG-DPPC, or a PEG-DSPE lipid.

[0276] In some embodiments the PEG-modified lipids are a modified form of PEG DMG. PEG-DMG has the following structure:

[0277] In one embodiment, PEG lipids useful in the present disclosure can be PEGylated lipids described in International Publication No. WO2012099755. Any of these exemplary PEG lipids described herein may be modified to comprise a hydroxyl group on the PEG chain. In certain embodiments, the PEG lipid is a PEG-OH lipid. As generally defined herein, a "PEG-OH lipid" (also referred to herein as "hydroxy-PEGylated lipid") is a PEGylated lipid having one or more hydroxyl (-OH) groups on the lipid. In certain embodiments, the PEG-OH lipid includes one or more hydroxyl groups on the PEG chain. In certain embodimetns, a PEG-OH or hydroxy-PEGylated lipid comprises an -OH group at the terminus of the PEG chain.PEG and PEG-OH Lipids

[0278] In certain embodiments, a PEG lipid useful in the present disclosure is a compound of Formula (III ). Provided herein are compounds of Formula (III ): or salts thereof, wherein: R 3 is -OR O< ; R O< is hydrogen, optionally substituted alkyl, or an oxygen protecting group; r is an integer between 1 and 100, inclusive; L 1< is optionally substituted C 1-10 alkylene, wherein at least one methylene of the optionally substituted C 1-10 alkylene is independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -O-, -N(R N< )-, -S-, -C(O)-, -C(O)N(R N< )-, - NR N< C(O)-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, or - NR N< C(O)N(R N< )-; D is a moiety obtained by click chemistry or a moiety cleavable under physiological conditions; m is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; A is of the formula: each instance of L 2< is independently a bond or optionally substituted C 1-6 alkylene, wherein one methylene unit of the optionally substituted C 1-6 alkylene is optionally replaced with O , N(R N< )-, -S-, -C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -C(O)O-, -OC(O)-, - OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, or -NR N< C(O)N(R N< )-; each instance of R 2 is independently optionally substituted C 1-30 alkyl, optionally substituted C 1-30 alkenyl, or optionally substituted C 1-30 alkynyl; optionally wherein one or more methylene units of R 2< are independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-, - NR N< C(O)-, -NR N< C(O)N(RN)-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(O)N(R N< )-, - NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-, -NR N< C(=NR N< )-, - NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-, - OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-, - S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, -N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, -OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group; Ring B is optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, or optionally substituted heteroaryl; and p is 1 or 2.

[0279] In certain embodiments, the compound of Fomula (III ) is a PEG-OH lipid (i.e., R 3< is -OR O< , and R O< is hydrogen). In certain embodiments, the compound of Formula (III ) is of Formula (III-OH ): or a salt thereof.

[0280] In certain embodiments, D is a moiety obtained by click chemistry (e.g., triazole). In certain embodiments, the compound of Formila (III ) is of Formula (III-a-1 ) or (III-a-2 ): or a salt thereof.

[0281] In certain embodiments, the compound of Formula (III ) is of one of the following formulae: or a salt thereof, wherein s is 0, 1, 2, 3, 4, 5, 6, 7, 8. 9, or 10.

[0282] In certain embodiments, the compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0283] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or a salt thereof

[0284] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0285] In certain embodiments, D is a moiety cleavable under physiological conditions (e.g., ester, amide, carbonate, carbamate, urea). In certain embodiments, a compound of Formula (III ) is of Formula (III-b-1 ) or (III-b-2 ): or a salt thereof.

[0286] In certain embodiments, a compound of Formula (III ) is of Formula (III-b-1-OH ) or (III-b-2-OH ): or a salt thereof.

[0287] In certain embodiments, the compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0288] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0289] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or a salt thereof.

[0290] In certain embodiments, a compound of Formula (III ) is of one of the following formulae: or salts thereof.

[0291] In certain embodiments, a PEG lipid useful in the present disclosure is a PEGylatcd fatty acid. In certain embodiments, a PEG lipid useful in the present disclosure is a compound of Formula (V). Provided herein are compounds of Formula (V): or a salts thereof, wherein: R 3< is-OR O< ; R O< is hydrogen, optionally substituted alkyl or an oxygen protecting group; r is an integer between 1 and 100, inclusive; R 5< is optionally substituted C 10-40 alkyl, optionally substituted C 10-40 alkenyl, or optionally substituted C 10-40 alkynyl; and optionally one or more methylene groups of R 5< are replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, - C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-,-OC(O)N(R N< )-, -NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-,-NR N< C(=NR N< )-, -NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-,-NR N< C(S)N(R N< )-, -S(O)-, -OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-,-OS(O) 2 O-, -N(R N< )S(O)-, -S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-,-N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-,-OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; and each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group.

[0292] In embodiments of the invention, the compound of Formula (V) is of Formula (V-OII): or a salt thereof.

[0293] In certain embodiments, a compound of Formula (V) is of one of the following formulae: or a salt thereof.

[0294] Numerous LNP formulations having different PEG-lipids were prepared and tested for activity, as demonstrated in the Examples included below.Phospholipids, including helper phospholipids

[0295] Phospholipids, as defined herein, are any lipids that comprise a phosphate group. Phospholipids are a subset of non-cationic lipids. The lipid component of a nanoparticlc composition may include one or more phospholipids, such as one or more (poly)unsaturated lipids. Phospholipids may assemble into one or more lipid bilayers. In general, phospholipids may include a phospholipid moiety and one or more fatty acid moieties. A phospholipid moiety may be selected from the non-limiting group consisting of phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl serine, phosphatidic acid, 2-lysophosphatidyl choline, and a sphingomyelin. A fatty acid moiety may be selected from the non-limiting group consisting of lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, alpha-linolenic acid, erucic acid, phytanoic acid, arachidic acid, arachidonic acid, eicosapentaenoic acid, behenic acid, docosapentaenoic acid, and docosahexaenoic acid. Non-natural species including natural species with modifications and substitutions including branching, oxidation, cyclization, and alkynes are also contemplated. For example, a phospholipid may be functionalized with or cross-linked to one or more alkynes (e.g., an alkenyl group in which one or more double bonds is replaced with a triple bond). Under appropriate reaction conditions, an alkync group may undergo a copper-catalyzed cycloaddition upon exposure to an azide. Such reactions may be useful in functionalizing a lipid bilayer of a nanoparticle composition to facilitate membrane permeation or cellular recognition or in conjugating a nanoparticle composition to a useful component such as a targeting or imaging moiety (e.g., a dye). Each possibility represents a separate embodiment of the present invention.

[0296] Phospholipids useful in the compositions and methods may be selected from the non-limiting group consisting of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-diolcoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLPC), 1,2-dimyrisloyl-sn-glycero-phosphocholine (DMPC), 1,2 dioleoyl sn glyoero 3 phosphocholine (DOPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-diundecanoyl-sn-glycero-phosphocholine (DUPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1,2-di-O-octadecenyl-sn-glycero-3-phosphocholine (18:0 Diether PC), 1-oleoyl-2-cholesterylhemisuccinoyl-sn-glycero-3-phosphocholine (OChemsPC), 1-hexadecyl-sn-glycero-3-phosphocholine (C16 Lyso PC), 1,2-dilinolenoyl-sn-glycero-3-phosphocholine, 1,2-diarachidonoyl-sn-glycero-3-phosphocholine, 1,2-didocosahexaenoyl-sn-glyccro-3-phosphocholine, 1,2-diphytanoyl-sn-glycero-3-phosphoethanolamine (ME 16.0 PE), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine, 1,2-dilinoleoyl-sn-glycero-3-phosphoethanolamine, 1,2-dilinolenoyl-sn-glycero-3-phosphoethanolamine, 1,2-diarachidonoyl-sn-glycero-3-phosphoethanolamine, 1,2-didocosahexaenoyl-sn-glycero-3-phosphoethanolamine, 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG), and sphingomyelin. Each possibility represents a separate embodiment of the present invention.

[0297] In some embodiments, a nanoparticle composition includes DSPC. In certain embodiments, a nanoparticle composition includes DOPE. In some embodiments, a nanoparticle composition includes both DSPC and DOPE. Examples of phospholipids include, but are not limited to, the following: and

[0298] In certain embodiments, a phospholipid useful in the present invention is an analog or variant of DSPC. In certain embodiments, a phospholipid useful in the present invention is a compound of Formula (I ): or a salt thereof, wherein: each R 1< is independently optionally substituted alkyl; or optionally two R 1< are joined together with the intervening atoms to form optionally substituted monocyclic carbocyclyl or optionally substituted monocyclic heterocyclyl; or optionally three R 1< are joined together with the intervening atoms to form optionally substituted bicyclic carbocyclyl or optionally substitute bicyclic heterocyclyl; n is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; m is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; A is of the formula: each instance of L 2< is independently a bond or optionally substituted C 1-6 alkylene, wherein one methylene unit of the optionally substituted C 1-6 alkylene is optionally replaced with -O-. -N(R N< )-, -S-, -C(O)-, -C(O)N(R N< )-, -NR N< C(O)-, -C(O)O-, -OC(O)-,-OC(O)O-, -OC(O)N(R N< )-, -NR N< C(O)O-, or -NR N< C(O)N(R N< )-; each instance of R 2< is independently optionally substituted C 1-30 alkyl, optionally substituted C 1-30 alkenyl, or optionally substituted C 1-30 alkynyl; optionally wherein one or more methylene units of R 2< are independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-,-NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(O)N(R N< )-,-NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-, -NR N< C(=NR N< )-,-NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-,-OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-,-S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, -N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, -OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-; each instance of R N< is independently hydrogen, optionally substituted alkyl, or a nitrogen protecting group; Ring B is optionally substituted carbocyclyl, optionally substituted heterocyclyl, optionally substituted aryl, or optionally substituted heteroaryl; and p is 1 or 2; provided that the compound is not of the formula: wherein each instance of R 2< is independently unsubstituted alkyl, unsubstituted alkenyl, or unsubstituted alkynyl. Phospholipid Head Modifications

[0299] In certain embodiments, a phospholipid useful in the present invention comprises a modified phospholipid head (e.g., a modified choline group). In certain embodiments, a phospholipid with a modified head is DSPC, or analog thereof, with a modified quaternary amine. For example, in embodiments of Formula (I ), at least one of R 1< is not methyl. In certain embodiments, at least one of R 1< is not hydrogen or methyl. In certain embodiments, the compound of Formula (I ) is of one of the following formulae: or a salt thereof, wherein: each t is independently 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; each u is independently 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10; and each v is independently 1, 2, or 3.

[0300] In certain embodiments, the compound of Formula (I ) is of one of the following formulae: or a salt thereof.

[0301] In certain embodiments, a compound of Formula (I ) is one of the following: or a salt thereof.Phospholipid Core Modifications

[0302] In certain embodiments, a compound of Formula (I ) is of Formula (I-a ): or a salt thereof.

[0303] In certain embodiments, phospholipids useful in the present invention comprise a modified core (see, e.g., FIG 47B). In certain embodiments, a phospholipid with a modified core described herein is DSPC, or analog thereof, with a modified core structure. For example, in certain embodiments of Formula (I-a ), group A is not of the following formula:

[0304] In certain embodiments, the compound of Formula (I-a) is of one of the following formulae: or a salt thereof.

[0305] In certain embodiments, a compound of Formula (I ) is one of the following: or sails thereof.

[0306] In certain embodiments, a phospholipid useful in the present invention comprises a cyclic moiety in place of the glyceride moiety. In certain embodiments, a phospholipid useful in the present invention is DSPC, or analog thereof, with a cyclic moiety in place of the glyceride moiety. In certain embodiments In certain embodiments, the compound of Formula (I ) is of Formula (I-b ): or a salt thereof.

[0307] In certain embodiments, the compound of Formula (I-b ) is of Formula (I-b-1 ): or a salt thereof, wherein: w is 0, 1, 2, or 3.

[0308] In certain embodiments, the compound of Formula (I-b ) is of Formula (I-b-2 ): or a salt thereof.

[0309] In certain embodiments, the compound of Formula (I-b ) is of Formula (I-b-3 ): or a salt thereof.

[0310] In certain embodiments, the compound of Formula (I-b ) is of Formula (I-b-4 ): or a salt thereof.

[0311] In certain embodiments, the compound of Formula (I-b ) is one of the following: or salts thereof.Phospholipid Tail Modifications

[0312] In certain embodiments, a phospholipid useful in the present invention comprises a modified tail. In certain embodiments, a phospholipid useful in the present invention is DSPC, or analog thereof, with a modified tail. As described herein, a "modified tail" may be a tail with shorter or longer aliphatic chains, aliphatic chains with branching introduced, aliphatic chains with substituents introduced, aliphatic chains wherein one or more methylenes are replaced by cyclic or heteroatom groups, or any combination thereof. For example, in certain embodiments, the compound of (I ) is of Formula (I-a ), or a salt thereof, wherein at least one instance of R 2< is each instance of R 2< is optionally substituted C 1-30 alkyl, wherein one or more methylene units of R 2< are independently replaced with optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-,-NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(C))N(R N< )-,-NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(-NR N< )N(R N< )-, -NR N< C(=NR N< )-,-NR N< C(=NR N< )N(R N< )-, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-,-OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2 -, -S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-,-S(O)N(R N< )-. -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, -N(R N< )S(O) 2 N(R N< )-, -OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-.

[0313] In certain embodiments, the compound of Formula (I-a) is of Formula (I-c ): or a salt thereof, wherein: each x is independently an integer between 0-30, inclusive; and each instance is G is independently selected from the group consisting of optionally substituted carbocyclylene, optionally substituted heterocyclylene, optionally substituted arylene, optionally substituted heteroarylene, -N(R N< )-, -O-, -S-, -C(O)-, -C(O)N(R N< )-, - NR N< C(O)-, -NR N< C(O)N(R N< )-, -C(O)O-, -OC(O)-, -OC(O)O-, -OC(O)N(R N< )-,-NR N< C(O)O-, -C(O)S-, -SC(O)-, -C(=NR N< )-, -C(=NR N< )N(R N< )-, -NR N< C(=NR N< }-,-NR N< C(=NR N< )N(R N)< -, -C(S)-, -C(S)N(R N< )-, -NR N< C(S)-, -NR N< C(S)N(R N< )-, -S(O)-,-OS(O)-, -S(O)O-, -OS(O)O-, -OS(O) 2- , -S(O) 2 O-, -OS(O) 2 O-, -N(R N< )S(O)-,-S(O)N(R N< )-, -N(R N< )S(O)N(R N< )-, -OS(O)N(R N< )-, -N(R N< )S(O)O-, -S(O) 2 -, -N(R N< )S(O) 2 -, -S(O) 2 N(R N< )-, N(R N< )S(O) 2 N(R N< )-, -OS(O) 2 N(R N< )-, or -N(R N< )S(O) 2 O-. Each possibility represents a separate embodiment of the present invention.

[0314] In certain embodiments, the compound of Formula (I-c ) is of Formula (I-c-1 ): or salt thereof, wherein: each instance of v is independently 1, 2, or 3.

[0315] In certain embodiments, the compound of Formula (I-c ) is of Formula (I-c-2 ): or a salt thereof.

[0316] In certain embodimenrs, the compound of Formula (I-c) is of the following formula: or a salt thereof.

[0317] In certain embodiments, the compound of Formula (I-c) is the following: or a salt thereof.

[0318] In certain embodiments, the compound of Formula (I-c) is of Formula (I-c-3 ): or a salt thereof.

[0319] In certain embodiments, the compound of Formula (I-c) is of the following formulae: or a salt thereof.

[0320] In certain embodiments, the compound of Formula (I-c) is the following: or a salt thereof.Phosphocholine Linker Modifications

[0321] In certain embodiments, a phospholipid useful in the present invention comprises a modified phosphocholine moiety, wherein the alkyl chain linking the quaternary amine to the phosphoryl group is not ethylene (e.g., n is not 2). Therefore, in certain embodiments, a phospholipid useful in the present invention is a compound of Formula (I ), wherein n is 1, 3, 4, 5, 6, 7, 8, 9, or 10. For example, in certain embodiments, a compound of Formula (I ) is of one of the following formulae: or a salt thereof.

[0322] In certain embodiments, a compound of Formula (I ) is one of the following: or salts thereof.

[0323] Numerous LNP formulations having phospholipids other than DSPC were prepared and tested for activity, as demonstrated in the examples below. Exemplary phospholipids are shown in the Figures, including Figs. 75A, 75D and 75Emissing.

[0324] The following Table provides a summary of the phospholipids and indicates which examples include data on the phospholipids. Compound Name Common Name Example testing lipid Formulation Oleic acidOL23MC3:OL:Chol:PEG-DMGCmpd393Trialkyl25MC3:PC:Chol:PEG-DMGCmpd125Dialkyl23MC3:PC:Chol:PEG-DMGCmpd-148OL25MC3:OL:Chol:PEG-DMGCmpd- 149OL23MC3:OL:Chol:PEG-DMGCmpd-150PC23MC3:PC:Chol:PEG-DMGCmpd-151PC23MC3:PC:Chol:PEG-DMGCmpd-152PC23MC3:PC:Chol:PEG-DMGCmpd-153PC23MC3:PC:Chol:PEG-DMGDOPCPC22MC3:PC:Chol:PEG-DMGOleic addFA22MC3:PC:Chol:PEG-DMGDOCPPC22MC3:PC:Chol:PEG-DMGDOCPePC22MC3:PC:Chol:PEG-DMGDOPEPE22MC3:PC:Chol:PEG-DMGDOPGPG22MC3:PC:Chol:PEG-DMGDOPAPA22MC3:PC:Chol:PEG-DMGDOPS 0.1%PS22MC3:OL:Chol:PEG-DMGDOPS 1%PS22MC3:OL:Chol:PEG-DMGDOPS 1%PS22MC3:PC:Chol:PEG-DMGCmpd-279PC23MC3:PC:Chol:PEG-DMGCmpd-280PC23MC3:PC:Chol:PEG-DMGCmpd-281PC23MC3:PC:Chol:PEG-DMGCmpd-160PC25MC3:PC:Chol:PEG-DMGCmpd-161PC25MC3:PC:Chol:PEG-DMGCmpd-162PC25MC3:PC:Chol:PEG-DMGCmpd-163PC25MC3:PC:Chol:PEG-DMGCmpd-157OL25MC3:OL:Chol:PEG-DMGCmpd-158OL25MC3:OL:Chol:PEG-DMGCmpd-159OL25MC3:OL:Chol:PEG-DMGCmpd-164PC25MC3:PC:Chol:PEG-DMGCmpd-165PC25MC3:PC:Chol:PEG-DMGCmpd-166PC25MC3:PC:Chol:PEG-DMGDSPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)DPPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)DMPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)SMPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)OMPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)SPPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)OPPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:30.5:1.5)PSPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)POPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)PLPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)PMPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)MSPCPC24Cmpd18:PC:Chol:PEG-DMG (50:1-:38.5:1.5)Steric acidOL24Oleic AcidOL24Linoleic AcidOL24 Structural lipids

[0325] The lipid component of a nanoparticle composition may include one or more structural lipids. Incorporation of structural lipids in the lipid nanoparticle may help mitigate aggregation of other lipids in the particle. Structural lipids can be selected from the group consisting of, but are not limited to, cholesterol, fecosterol, sitosterol, ergosterol, campesterol, stigmasterol, brassicasterol, tomatidine, tomatine, ursolic acid, alpha-tocopherol, hopanoids, phytosterols, steroids, and mixtures thereof. In some embodiments, the structural lipid is a sterol. As defined herein, "sterols" are a subgroup of steroids consisting of steroid alcohols. In certain embodiments, the structural lipid is a steroid. In certain embodiments, the structural lipid is cholesterol. In certain embodiments, the structural lipid is an analog of cholesterol. In certain embodiments, the structural lipid is alpha-tocopherol. Examples of structural lipids include, but are not limited to, the following: and Chemical Definitions

[0326] Definitions of specific functional groups and chemical terms are described in more detail below. The chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75 th< Ed., inside cover, and specific functional groups are generally defined as described therein. Additionally, general principles of organic chemistry, as well as specific functional moieties and reactivity, arc described in Organic Chemistry. Thomas Sorrell, University Science Books, Sausalito, 1999; Smith and March, March's Advanced Organic Chemistry, 5th Edition, John Wiley & Sons, Inc., New York, 2001; Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., New York, 1989; and Carruthers, Some Modern Methods of Organic Synthesis, 3rd Edition, Cambridge University Press, Cambridge, 1987.

[0327] Compounds described herein can comprise one or more asymmetric centers, and thus can exist in various stereoisomeric forms, e.g., enantiomers and / or diastereomers. For example, the compounds described herein can be in the form of an individual enantiomer, diastereomer or geometric isomer, or can be in the form of a mixture of stereoisomers, including racemic mixtures and mixtures enriched in one or more stereoisomer. Isomers can be isolated from mixtures by methods known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts; or preferred isomers can be prepared by asymmetric syntheses. See, for example, Jacques et al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen et al., Tetrahedron 33:2725 (1977); Eliel, E.L. Stereochemistry of Carbon Compounds (McGraw-Hill, NY, 1962); and Wilen, S.H., Tables of Resolving Agents and Optical Resolutions p. 268 (E.L. Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, IN 1972). The invention additionally encompasses compounds as individual isomers substantially free of other isomers, and alternatively, as mixtures of various isomers.

[0328] In a formula, is a single bond where the stereochemistry of the moieties immediately attached thereto is not specified, --- is absent or a single bond, and or is a single or double bond.

[0329] Unless otherwise stated, structures depicted herein are also meant to include compounds that differ only in the presence of one or more isotopically enriched atoms. For example, compounds having the present structures except for the replacement of hydrogen by deuterium or tritium, replacement of 19< F with 18< F, or the replacement of 12< C with 13< C or 14< C are within the scope of the disclosure. Such compounds are useful, for example, as analytical tools or probes in biological assays.

[0330] When a range of values is listed, it is intended to encompass each value and sub-range within the range. For example "C 1-6 alkyl" is intended to encompass, C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 1-6 , C 1-5 , C 1-4 , C 1-3 , C 1-2 , C 2-6 , C 2-5 , C 2-4 , C 2-3 , C 3-6 , C 3-5 , C 3-4 , C 4-6 , C 4-3 , and C 5-6 alkyl.

[0331] The term "aliphatic" refers to alkyl, alkenyl, alkynyl, and carbocyclic groups. Likewise, the term "heteroaliphatic" refers to heteroalkyl, heteroalkenyl, heteroalkynyl, and heterocyclic groups.

[0332] The term "alkyl" refers to a radical of a straight-chain or branched saturated hydrocarbon group having from 1 to 10 carbon atoms ("C 1-10 alkyl"). In some embodiments, an alkyl group has 1 to 9 carbon atoms ("C 1-9 alkyl"). In some embodiments, an alkyl group has 1 to 8 carbon atoms ("C 1-8 alkyl"). In some embodiments, an alkyl group has 1 to 7 carbon atoms ("C 1-7 alkyl"). In some embodiments, an alkyl group has 1 to 6 carbon atoms ("C 1-6 alkyl"). In some embodiments, an alkyl group has 1 to 5 carbon atoms ("C 1-5 alkyl"). In some embodiments, an alkyl group has 1 to 4 carbon atoms ("C 1-4 alkyl"). In some embodiments, an alkyl group has 1 to 3 carbon atoms ("C 1-3 alkyl"). In some embodiments, an alkyl group has 1 to 2 carbon atoms ("C 1-2 alkyl"). In some embodiments, an alkyl group has 1 carbon atom ("C 1 alkyl"). In some embodiments, an alkyl group has 2 to 6 carbon atoms ("C 2-6 alkyl"). Examples of C 1-6 alkyl groups include methyl (C 1 ), ethyl (C 2 ), propyl (C 3 ) (e.g., n-propyl, isopropyl), butyl (C 4 ) (e.g., n-butyl, tert-butyl, sec-butyl, iso-butyl), pentyl (C 5 ) (e.g., n-pentyl, 3-pentanyl, amyl, neopentyl, 3-methyl-2-butanyl, tertiary amyl), and hexyl (C 6 ) (e.g., n-hexyl). Additional examples of alkyl groups include n-heptyl (C 7 ), n-octyl (C 8 ), and the like. Unless otherwise specified, each instance of an alkyl group is independently unsubstituted (an "unsubstituted alkyl") or substituted (a "substituted alkyl") with one or more substituents (e.g., halogen, such as F). In certain embodiments, the alkyl group is an unsubstituted C 1-10 alkyl (such as unsubstituted C 1-6 alkyl, e.g., -CH 3 (Me), unsubstituted ethyl (Et), unsubstituted propyl (Pr, e.g., unsubstituted n-propyl (n-Pr), unsubstituted isopropyl (i-Pr)), unsubstituted butyl (Bu, e.g., unsubstituted n-butyl (n-Bu), unsubstituted tert-butyl (tert-Bu or t-Bu), unsubstituted sec-butyl (sec-Bu), unsubstituted isobutyl (i-Bu)). In certain embodiments, the alkyl group is a substituted C 1-10 alkyl (such as substituted C 1-6 alkyl, e.g., -CF 3 , Bn).

[0333] The term "haloalkyl" is a substituted alkyl group, wherein one or more of the hydrogen atoms are independently replaced by a halogen, e.g., fluoro, bromo, chloro, or iodo. In some embodiments, the haloalkyl moiety has 1 to 8 carbon atoms ("C 1-8 haloalkyl"). In some embodiments, the haloalkyl moiety has 1 to 6 carbon atoms ("C 1-6 haloalkyl"). In some embodiments, the haloalkyl moiety has 1 to 4 carbon atoms ("C 1-4 haloalkyl"). In some embodiments, the haloalkyl moiety has 1 to 3 carbon atoms ("C 1-3 haloalkyl"). In some embodiments, the haloalkyl moiety has 1 to 2 carbon atoms ("C 1-2 haloalkyl"). Examples of haloalkyl groups include -CHF 2 , -CH 2 F, -CF 3 , -CH 2 CF 3 , -CF 2 CF 3 , -CF 2 CF 2 CF 3 , -CCl 3 . -CFCl 2 , -CF 2 Cl, and the like.

[0334] The term "heteroalkyl" refers to an alkyl group, which further includes at least one heteroatom (e.g., 1, 2, 3, or 4 heteroatoms) selected from oxygen, nitrogen, or sulfur within (i.e., inserted between adjacent carbon atoms of) and / or placed at one or more terminal position(s) of the parent chain. In certain embodiments, a heteroalkyl group refers to a saturated group having from 1 to 10 carbon atoms and 1 or more heteroatoms within the parent chain ("heteroC 1-10 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 to 9 carbon atoms and 1 or more heteroatoms within the parent chain ("heteroC 1-9 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 to 8 carbon atoms and 1 or more heteroatoms within the parent chain ("heteroC 1-8 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 to 7 carbon atoms and 1 or more heteroatoms within the parent chain ("heteroC 1-7 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 to 6 carbon atoms and 1 or more heteroatoms within the parent chain ("heteroC 1-6 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 to 5 carbon atoms and 1 or 2 heteroatoms within the parent chain ("heteroC 1-5 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 to 4 carbon atoms and 1or 2 heteroatoms within the parent chain ("heteroC 1-4 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 to 3 carbon atoms and 1 heteroatom within the parent chain ("heteroC 1-3 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 to 2 carbon atoms and 1 heteroatom within the parent chain ("heteroC 1-2 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 1 carbon atom and 1 heteroatom ("heteroC 1 alkyl"). In some embodiments, a heteroalkyl group is a saturated group having 2 to 6 carbon atoms and 1 or 2 heteroatoms within the parent chain ("heteroC 2-6 alkyl"). Unless otherwise specified, each instance of a heteroalkyl group is independently unsubstituted (an "unsubstituted heteroalkyl") or substituted (a "substituted heteroalkyl") with one or more substituents. In certain embodiments, the heteroalkyl group is an unsubstituted heteroC 1-10 alkyl. In certain embodiments, the heteroalkyl group is a substituted heteroC 1-10 alkyl.

[0335] The term "alkenyl" refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 10 carbon atoms and one or more carbon-carbon double bonds (e.g., 1, 2, 3, or 4 double bonds). In some embodiments, an alkenyl group has 2 to 9 carbon atoms ("C 2-9 alkenyl"). In some embodiments, an alkenyl group has 2 to 8 carbon atoms ("C 2-8 alkenyl"). In some embodiments, an alkenyl group has 2 to 7 carbon atoms ("C 2-7 alkenyl"). In some embodiments, an alkenyl group has 2 to 6 carbon atoms ("C 2-6 alkenyl"). In some embodiments, an alkenyl group has 2 to 5 carbon atoms ("C 2-5 alkenyl"). In some embodiments, an alkenyl group has 2 to 4 carbon atoms ("C 2-4 alkenyl"). In some embodiments, an alkenyl group has 2 to 3 carbon atoms ("C 2-3 alkenyl"). In some embodiments, an alkenyl group has 2 carbon atoms ("C 2 alkenyl"). The one or more carbon-carbon double bonds can be internal (such as in 2-butenyl) or terminal (such as in 1-butenyl). Examples of C 2-4 alkenyl groups include ethenyl (C 2 ), 1-propenyl (C 3 ), 2-propenyl (C 3 ), 1-butenyl (C 4 ), 2-butenyl (C 4 ), butadienyl (C 4 ), and the like. Examples of C 2-6 alkenyl groups include the aforementioned C 2-4 alkenyl groups as well as pentenyl (C 5 ), pentadienyl (C 8 ), hexenyl (C 6 ), and the like. Additional examples of alkenyl include heptenyl (C 7 ), octenyl (C 8 ), octatrienyl (C 8 ), and the like. Unless otherwise specified, each instance of an alkenyl group is independently unsubstituted (an "unsubstituted alkenyl") or substituted (a "substituted alkenyl") with one or more substituents. In certain embodiments, the alkenyl group is an unsubstituted C 2-10 alkenyl. In certain embodiments, the alkenyl group is a substituted C 2-10 alkenyl. In an alkenyl group, a C=C double bond for which the stereochemistry is not specified (e.g., -CH=CHCH 3 or may be an (E)- or (Z)-double bond.

[0336] The term "heteroalkenyl" refers to an alkenyl group, which further includes at least one heteroatom (e.g., 1, 2, 3, or 4 heteroatoms) selected from oxygen, nitrogen, or sulfur within (i.e., inserted between adjacent carbon atoms of) and / or placed at one or more terminal position(s) of the parent chain. In certain embodiments, a heteroalkenyl group refers to a group having from 2 to 10 carbon atoms, at least one double bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-10 alkenyl"). In some embodiments, a heteroalkenyl group has 2 to 9 carbon atoms at least one double bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-9 alkenyl")- In some embodiments, a heteroalkenyl group has 2 to 8 carbon atoms, at least one double bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-8 alkenyl"). In some embodiments, a heteroalkenyl group has 2 to 7 carbon atoms, at least one double bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-7 alkenyl"). In some embodiments, a heteroalkenyl group has 2 to 6 carbon atoms, at least one double bond, and l or more heteroatoms within the parent chain ("heteroC 2-6 alkenyl"). In some embodiments, a heteroalkenyl group has 2 to 5 carbon atoms, at least one double bond, and 1 or 2 heteroatoms within the parent chain ("heteroC 2-5 alkenyl"). In some embodiments, a heteroalkenyl group has 2 to 4 carbon atoms, at least one double bond, and 1or 2 heteroatoms within the parent chain ("heteroC 2-4 alkenyl"). In some embodiments, a heteroalkenyl group has 2 to 3 carbon atoms, at least one double bond, and 1 heteroatom within the parent chain ("heteroC 2-3 alkenyl"). In some embodiments, a heteroalkenyl group has 2 to 6 carbon atoms, at least one double bond, and 1 or 2 heteroatoms within the parent chain ("heteroC 2-6 alkenyl"). Unless otherwise specified, each instance of a heteroalkenyl group is independently unsubstituted (an "unsubstituted heteroalkenyl") or substituted (a "substituted heteroalkenyl") with one or more substituents. In certain embodiments, the heteroalkenyl group is an unsubstituted heteroC 2-10 alkenyl. In certain embodiments, the heteroalkenyl group is a substituted heteroC 2-10 alkenyl.

[0337] The term "alkynyl" refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 10 carbon atoms and one or more carbon-carbon triple bonds (e.g., 1, 2, 3, or 4 triple bonds) ("C 2-10 alkynyl"). In some embodiments, an alkynyl group has 2 to 9 carbon atoms ("C 2-9 alkynyl"). In some embodiments, an alkynyl group has 2 to 8 carbon atoms ("C 2-8 alkynyl"). In some embodiments, an alkynyl group has 2 to 7 carbon atoms ("C 2-7 alkynyl"). In some embodiments, an alkynyl group has 2 to 6 carbon atoms ("C 2-6 alkynyl"). In some embodiments, an alkynyl group has 2 to 5 carbon atoms ("C 2-5 alkynyl"). In some embodiments, an alkynyl group has 2 to 4 carbon atoms ("C 2-4 alkynyl"). In some embodiments, an alkynyl group has 2 to 3 carbon atoms ("C 2-3 alkynyl"). In some embodiments, an alkynyl group has 2 carbon atoms ("C 2 alkynyl"). The one or more carbon-carbon triple bonds can be internal (such as in 2-butynyl) or terminal (such as in 1-butynyl). Examples of C 2-4 alkynyl groups include, without limitation, ethynyl (C 2 ), 1-propynyl (C 3 ), 2-propynyl (C 3 ), 1-botynyl (C 4 ), 2-butynyl (C 4 ), and the like. Examples of C 2-6 alkenyl groups include the aforementioned C 2-4 alkynyl groups as well as pentynyl (C 8 ), hexynyl (C 6 ), and the like. Additional examples of alkynyl include heptynyl (C 7 ), octynyl (C 8 ), and the like. Unless otherwise specified, each instance of an alkynyl group is independently unsubstituted (an "unsubstituted alkynyl") or substituted (a "substituted alkynyl") with one or more substituents. In certain embodiments, the alkynyl group is an unsubstituted C 2-10 alkynyl. In certain embodiments, the alkynyl group is a substituted C 2-10 alkynyl.

[0338] The term "heteroalkynyl" refers to an alkynyl group, which further includes at least one heteroatom (e.g., 1, 2, 3, or 4 heteroatoms) selected from oxygen, nitrogen, or sulfur within (i.e., inserted between adjacent carbon atoms of) and / or placed at one or more terminal position(s) of the parent chain. In certain embodiments, a heteroalkynyl group refers to a group having from 2 to 10 carbon atoms, at least one triple bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-10 alkynyl"). In some embodiments, a heteroalkynyl group has 2 to 9 carbon atoms, at least one triple bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-9 alkynyl"). In some embodiments, a heteroalkynyl group has 2 to 8 carbon atoms, at least one triple bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-8 alkynyl"). In some embodiments, a heteroalkynyl group has 2 to 7 carbon atoms, at least one triple bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-7 alkynyl"). In some embodiments, a heteroalkynyl group has 2 to 6 carbon atoms, at least one triple bond, and 1 or more heteroatoms within the parent chain ("heteroC 2-6 alkynyl"). In some embodiments, a heteroalkynyl group has 2 to 5 carbon atoms, at least one triple bond, and 1 or 2 heteroatoms within the parent chain ("heteroC 2-3 alkynyl"). In some embodiments, a heteroalkynyl group has 2 to 4 carbon atoms, at least one triple bond, and 1 or 2 heteroatoms within the parent chain ("heteroC 2-4 alkynyl"). In some embodiments, a heteroalkynyl group has 2 to 3 carbon atoms, at least one triple bond, and 1 heteroatom within the parent chain ("heteroC 2-3 alkynyl"). In some embodiments, a heteroalkynyl group has 2 to 6 carbon atoms, at least one triple bond, and 1 or 2 heteroatoms within the parent chain ("heteroC 2-6 alkynyl"). Unless otherwise specified, each instance of a heteroalkynyl group is independently unsubstituted (an "unsubstituted heteroalkynyl") or substituted (a "substituted heteroalkynyl") with one or more substituents. In certain embodiments, the heteroalkynyl group is an unsubstituted heteroC 2-10 alkynyl. In certain embodiments, the heteroalkynyl group is a substituted heteroC 2-10 alkynyl.

[0339] The term "carbocyclyl" or "carbocyclic" refers to a radical of a non-aromatic cyclic hydrocarbon group having from 3 to 14 ring carbon atoms ("C 3-14 carbocyclyl") and zero heteroatoms in the non-aromatic ring system. In some embodiments, a carbocyclyl group has 3 to 10 ring carbon atoms ("C 3-10 carbocyclyl"). In some embodiments, a carbocyclyl group has 3 to 8 ring carbon atoms ("C 3-8 carbocyclyl"). In some embodiments, a carbocyclyl group has 3 to 7 ring carbon atoms ("C 3-7 carbocyclyl"). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms ("C 3-6 carbocyclyl"). In some embodiments, a carbocyclyl group has 4 to 6 ring carbon atoms ("C 4-6 carbocyclyl"). In some embodiments, a carbocyclyl group has 5 to 6 ring carbon atoms ("C 5-6 carbocyclyl"). In some embodiments, a carbocyclyl group has 5 to 10 ring carbon atoms ("C 5-10 carbocyclyl"). Exemplary C 3-6 carbocyclyl groups include, without limitation, cyclopropyl (C 3 ), cyclopropenyl (C 3 ), cyclobutyl (C 4 ), cyclobutenyl (C 4 ), cyclopentyl (C 3 ), cyclopentenyl (C 8 ), cyclohexyl (C 6 ), cyclohexenyl (C 6 ), cyclohexadienyl (C 6 ), and the like. Exemplary C 3-8 carbocyclyl groups include, without limitation, the aforementioned C 3-6 carbocyclyl groups as well as cycloheptyl (C 3 ), cycloheptenyl (C 7 ), cycloheptadienyl (C 7 ), cycloheptatrienyl (C 7 ), cyclooctyl (C 5 ), cyclooctenyl (C 8 ), bicyclo[2.2.1]heptanyl (C 7 ), bicyclo[2.2.2]octanyl (C 8 ), and the like. Exemplary C 3-10 carbocyclyl groups include, without limitation, the aforementioned C 3-8 carbocyclyl groups as well as cyclononyl (C 9 ), cyclononenyl (C 9 ), cyclodecyl (C 10 ), cyclodecenyl (C 10 ), octahydro-1H-indenyl (C 9 ), decahydronaphthalenyl (C 10 ), spiro[4.5]decanyl (C 10 ), and the like. As the foregoing examples illustrate, in certain embodiments, the carbocyclyl group is either monocyclic ("monocyclic carbocyclyl") or polycyclic (e.g., containing a fused, bridged or spiro ring system such as a bicyclic system ("bicyclic carbocyclyl") or tricyclic system ("tricyclic carbocyclyl")) and can be saturated or can contain one or more carbon-carbon double or triple bonds. "Carbocyclyl" also includes ring systems wherein the carbocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups wherein the point of attachment is on the carbocyclyl ring, and in such instances, the number of carbons continue to designate the number of carbons in the carbocyclic ring system. Unless otherwise specified, each instance of a carbocyclyl group is independently unsubstituted (an "unsubstituted carbocyclyl") or substituted (a "substituted carbocyclyl") with one or more substituents. In certain embodiments, the carbocyclyl group is an unsubstituted C 3-14 carbocyclyl. In certain embodiments, the carbocyclyl group is a substituted C 3-14 carbocyclyl.

[0340] In some embodiments, "carbocyclyl" is a monocyclic, saturated carbocyclyl group having from 3 to 14 ring carbon atoms ("C 3-14 cycloalkyl"). In some embodiments, a cycloalkyl group has 3 to 10 ring carbon atoms ("C 3-10 cycloalkyl"). In some embodiments, a cycloalkyl group has 3 to 8 ring carbon atoms ("C 3-8 cycloalkyl"). In some embodiments, a cycloalkyl group has 3 to 6 ring carbon atoms ("C 3-6 cycloalkyl"). In some embodiments, a cycloalkyl group has 4 to 6 ring carbon atoms ("C 4-6 cycloalkyl"). In some embodiments, a cycloalkyl group has 5 to 6 ring carbon atoms ("C 5-6 cycloalkyl"). In some embodiments, a cycloalkyl group has 5 to 10 ring carbon atoms ("C 5-10 cycloalkyl"). Examples of C 5-6 cycloalkyl groups include cyclopentyl (C 5 ) and cyclohexyl (C 5 ), Examples of C 3-6 cycloalkyl groups include the aforementioned C 5-6 cycloalkyl groups as well as cyclopropyl (C 3 ) and cyclobutyl (C 4 ). Examples of C 3-8 cycloalkyl groups include the aforementioned C 3-6 cycloalkyl groups as well as cycloheptyl (C 7 ) and cyclooctyl (C 5 ), Unless otherwise specified, each instance of a cycloalkyl group is independently unsubstituted (an "unsubstituted cycloalkyl") or substituted (a "substituted cycloalkyl") with one or more substituents. In certain embodiments, the cycloalkyl group is an unsubstituted C 3-14 cycloalkyl. In certain embodiments, the cycloalkyl group is a substituted C 3-14 cycloalkyl.

[0341] The term "heterocyclyl" or "heterocyclic" refers to a radical of a 3- to 14-membered non-aromatic ring system having ring carbon atoms and 1 to 4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("3-14 membered heterocyclyl"). In heterocyclyl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. A heterocyclyl group can either be monocyclic ("monocyclic heterocyclyl") or polycyclic (e.g., a fused, bridged or spiro ring system such as a bicyclic system ("bicyclic heterocyclyl") or tricyclic system ("tricyclic heterocyclyl")), and can be saturated or can contain one or more carbon-carbon double or triple bonds. Heterocyclyl polycyclic ring systems can include one or more heteroatoms in one or both rings. "Heterocyclyl" also includes ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more carbocyclyl groups wherein the point of attachment is either on the carbocyclyl or heterocyclyl ring, or ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups, wherein the point of attachment is on the heterocyclyl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heterocyclyl ring system. Unless otherwise specified, each instance of heterocyclyl is independently unsubstituted (an "unsubstituted heterocyclyl") or substituted (a "substituted heterocyclyl") with one or more substituents. In certain embodiments, the heterocyclyl group is an unsubstituted 3-14 membered heterocyclyl. In certain embodiments, the heterocyclyl group is a substituted 3-14 membered heterocyclyl.

[0342] In some embodiments, a heterocyclyl group is a 5-10 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-10 membered heterocyclyl"). In some embodiments, a heterocyclyl group is a 5-8 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-8 membered heterocyclyl"). In some embodiments, a heterocyclyl group is a 5-6 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-6 membered heterocyclyl"). In some embodiments, the 5-6 membered heterocyclyl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclyl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclyl has 1 ring heteroatom selected from nitrogen, oxygen, and sulfur. Each possibility represents a separate embodiment of the present invention.

[0343] Exemplary 3-membered heterocyclyl groups containing 1 heteroatom include, without limitation, azirdinyl, oxiranyl, and thiiranyl. Exemplary 4-membered heterocyclyl groups containing 1 heteroatom include, without limitation, azetidinyl, oxetanyl, and thietanyl. Exemplary 5-membered heterocyclyl groups containing 1 heteroatom include, without limitation, tetrahydrofuranyl, dihydrofuranyl, tetrahydrothiophenyl, dihydrothiophenyl, pyrrolidinyl, dihydropyrrolyl, and pyrrolyl-2,5-dione. Exemplary 5-membered heterocyclyl groups containing 2 heteroatoms include, without limitation, dioxolanyl, oxathiolanyl and dithiolanyl. Exemplary 5-membered heterocyclyl groups containing 3 heteroatoms include, without limitation, triazolinyl, oxadiazolinyl, and thiadiazolinyl. Exemplary 6-membered heterocyclyl groups containing 1 heteroatom include, without limitation, piperidinyl, tetrahydropyranyl, dihydropyridinyl, and thianyl. Exemplary 6-membered heterocyclyl groups containing 2 heteroatoms include, without limitation, piperazinyl, morpholinyl, dithianyl, and dioxanyl. Exemplary 6-membered heterocyclyl groups containing 2 heteroatoms include, without limitation, triazinanyl. Exemplary 7-membered heterocyclyl groups containing 1 heteroatom include, without limitation, azepanyl, oxepanyl and thiepanyl. Exemplary 8-membered heterocyclyl groups containing 1 heteroatom include, without limitation, azocanyl, oxecanyl and thiocanyl. Exemplary bicyclic heterocyclyl groups include, without limitation, indolinyl, isoindolinyl, dihydrobenzofuranyl, dihydrobenzothienyl, tetrahydrobenzothienyl, tetrahydrobenzofuranyl, tetrahydroindolyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl, decahydroisoquinolinyl. octahydrochromenyl, octahydroisochromenyl, decahydronaphthyridinyl, decahydro-1,8-naphthyridinyl, octahydropyrrolo[3,2-b]pyrrole, indolinyl, phthalimidyl, naphthalimidyl, chromanyl, chromenyl, 1H-benzo[e][1,4]diazepinyl, 1,4,5,7-tetrahydropyrano[3,4-b]pyrrolyl, 5,6-dihydro-4H-furo[3,2-b]pyrrolyl, 6,7-dihydro-5H-furo[3,2-b]pyranyl, 5,7-dihydro-4H-thieno[2,3-c]pyranyl, 2,3-dihydro-1H-pyrrolo[2,3-b]pyridinyl, 2,3-dihydrofuro[2,3-b]pyridinyl, 4,5,6,7-tetrahydro-1H-pyrrolo[2,3-b]pyridinyl, 4,5,6,7-tetrahydrofuro[3,2-c]pyridinyl, 4,5,6,7-tetrahydrothieno[3,2-b]pyridinyl, 1,2,3,4-tetrahydro-1,6-naphthyridinyl, and the like.

[0344] The term "aryl" refers to a radical of a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 π electrons shared in a cyclic array) having 6-14 ring carbon atoms and zero heteroatoms provided in the aromatic ring system ("C 6-14 aryl"). In some embodiments, an aryl group has 6 ring carbon atoms ("C 6 aryl"; e.g., phenyl). In some embodiments, an aryl group has 10 ring carbon atoms ("C 10 aryl"; e.g., naphthyl such as 1-naphthyl and 2-naphthyl). In some embodiments, an aryl group has 14 ring carbon atoms ("C 14 aryl"; e.g., anthracyl). "Aryl" also includes ring systems wherein the aryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the radical or point of attachment is on the aryl ring, and in such instances, the number of carbon atoms continue to designate the number of carbon atoms in the aryl ring system. Unless otherwise specified, each instance of an aryl group is independently unsubstituted (an "unsubstituted aryl") or substituted (a "substituted aryl") with one or more substituents. In certain embodiments, the aryl group is an unsubstituted C 6-14 aryl. In certain embodiments, the aryl group is a substituted C 6-14 aryl.

[0345] The term "heteroaryl" refers to a radical of a 5-14 membered monocyclic or polycyclic (e.g., bicyclic, tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 14 π electrons shared in a cyclic array) having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-14 membered heteroaryl"). In heteroaryl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. Heteroaryl polycyclic ring systems can include one or more heteroatoms in one or both rings. "Heteroaryl" includes ring systems wherein the heteroaryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the point of attachment is on the heteroaryl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heteroaryl ring system. "Heteroaryl" also includes ring systems wherein the heteroaryl ring, as defined above, is fused with one or more aryl groups wherein the point of attachment is either on the aryl or heteroaryl ring, and in such instances, the number of ring members designates the number of ring members in the fused polycyclic (aryl / heteroaryl) ring system. Polycyclic heteroaryl groups wherein one ring does not contain a heteroatom (e.g., indolyl, quinolinyl, carbazolyl, and the like) the point of attachment can be on either ring, i.e., either the ring bearing a heteroatom (e.g., 2-indolyl) or the ring that does not contain a heteroatom (e.g., 5-indolyl).

[0346] In some embodiments, a heteroaryl group is a 5-10 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-10 membered heteroaryl"). In some embodiments, a heteroaryl group is a 5-8 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-8 membered heteroaryl"). In some embodiments, a heteroaryl group is a 5-6 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur ("5-6 membered heteroaryl"). In some embodiments, the 5-6 membered heteroaryl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has 1 ring heteroatom selected from nitrogen, oxygen, and sulfur. Unless otherwise specified, each instance of a heteroaryl group is independently unsubstituted (an "unsubstituted heteroaryl") or substituted (a "substituted heteroaryl") with one or more substituents. In certain embodiments, the heteroaryl group is an unsubstituted 5-14 membered heteroaryl. In certain embodiments, the heteroaryl group is a substituted 5-14 membered heteroaryl.

[0347] Exemplary 5-membered heteroaryl groups containing 1 heteroatom include, without limitation, pyrrolyl, furanyl, and thiophenyl. Exemplary 5-membered heteroaryl groups containing 2 heteroatoms include, without limitation, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, and isothiazolyl. Exemplary 5-membered heteroaryl groups containing 3 heteroatoms include, without limitation, triazolyl, oxadiazolyl, and thiadiazolyl. Exemplary 5-membered heteroaryl groups containing 4 heteroatoms include, without limitation, tetrazolyl. Exemplary 6-membered heteroaryl groups containing 1 heteroatom include, without limitation, pyridinyl. Exemplary 6-membered heteroaryl groups containing 2 heteroatoms include, without limitation, pyridazinyl, pyrimidinyl, and pyrazinyl. Exemplary 6-membered heteroaryl groups containing 3 or 4 heteroatoms include, without limitation, triazinyl and tetrazinyl, respectively. Exemplary 7-membered heteroaryl groups containing 1 heteroatom include, without limitation, azepinyl, oxepinyl, and thiepinyl. Exemplary 5,6-bicyclic heteroaryl groups include, without limitation, indolyl, isoindolyl, indazolyl, benzotriazolyl, benzothiophenyl, isobenzothiophenyl, benzofuranyl, benzoisofuranyl, benzimidazolyl, benzoxazolyl, benzisoxazolyl, benzoxadiazolyl, benzthiazolyl, benzisothiazolyl, benzthiadiazolyl, indolizinyl, and purinyl. Exemplary 6,6-bicyclic heteroaryl groups include, without limitation, naphthyridinyl, pteridinyl, quinolinyl, isoquinolinyl, cinnolinyl, quinoxalinyl, phthalazinyl, and quinazolinyl. Exemplary tricyclic heteroaryl groups include, without limitation, phenanthridinyl, dibenzofuranyl, carbazolyl, acridinyl, phenothiazinyl, phenoxazinyl and phenazinyl.

[0348] The term "unsaturated bond" refers to a double or triple bond. The term "unsaturated" or "partially unsaturated" refers to a moiety that includes at least one double or triple bond. The term "saturated" refers to a moiety that does not contain a double or triple bond, i.e., the moiety only contains single bonds.

[0349] Affixing the suffix "-ene" to a group indicates the group is a divalent moiety, e.g., alkylene is the divalent moiety of alkyl, alkenylene is the divalent moiety of alkenyl, alkynylene is the divalent moiety of alkynyl, heteroalkylene is the divalent moiety of heteroalkyl, heteroalkenylene is the divalent moiety of heteroalkenyl, heteroalkynylene is the divalent moiety of heteroalkynyl, carbocyclylene is the divalent moiety of carbocyclyl. heterocyclylene is the divalent moiety of heterocyclyl, arylene is the divalent moiety of aryl, and heteroarylene is the divalent moiety of heteroaryl.

[0350] A group is optionally substituted unless expressly provided otherwise. The term "optionally substituted" refers to being substituted or unsubstituted. In certain embodiments, alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl groups are optionally substituted. "Optionally substituted" refers to a group which may be substituted or unsubstituted (e.g., "substituted" or "unsubstituted" alkyl, "substituted" or "unsubstituted" alkenyl, "substituted" or "unsubstituted" alkynyl, "substituted" or "unsubstituted" heteroalkyl, "substituted" or "unsubstituted" heteroalkenyl, "substituted" or "unsubstituted" heteroalkynyl, "substituted" or "unsubstituted" carbocyclyl, "substituted" or "unsubstituted" heterocyclyl, "substituted" or "unsubstituted" aryl or "substituted" or "unsubstituted" heteroaryl group). In general, the term "substituted" means that at least one hydrogen present on a group is replaced with a permissible substituent, e.g., a substituent which upon substitution results in a stable compound, e.g., a compound which does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, or other reaction. Unless otherwise indicated, a "substituted" group has a substituent at one or more substitutable positions of the group, and when more than one position in any given structure is substituted, the substituent is either the same or different at each position. The term "substituted" is contemplated to include substitution with all permissible substituents of organic compounds, and includes any of the substituents described herein that results in the formation of a stable compound. The present invention contemplates any and all such combinations in order to arrive at a stable compound. For purposes of this invention, heteroatoms such as nitrogen may have hydrogen substituents and / or any suitable substituent as described herein which satisfy the valencies of the heteroatoms and results in the formation of a stable moiety. The invention is not intended to be limited in any manner by the exemplary substituents described herein.

[0351] Exemplary carbon atom substituents include, but are not limited to, halogen, -CN, -NO 2 , -N 3 , -SO 2 H, -SO 3 H, -OH, -OR aa< , -ON(R bb< ) 2 , -N(R bb< ) 2 , -N(R bb< ) 3 +< X -< , -N(OR cc< )R bb< , -SH, -SR aa< , -SSR cc< , -C(=O)R aa< , -CO 2 H, -CHO, -C(OR cc< ) 2 , -CO 2 R aa< , -OC(=O)R aa< , -OCO 2 R aa< , -C(=O)N(R b< ) 2 , -OC(=O)N(R bb< ) 2 , -NR bb< C(=O)R aa< , -NR bb< CO 2 R aa< , -NR bb< C(=O)N(R bb< ) 2 , -C(=NR bb< )R aa< , -C(=NR bb< )OR aa< , -OC(=NR bb< )R aa< , -OC(=NR bb< )OR aa< , -C(=NR bb< )N(R bb< ) 2 , -OC(=NR bb< )N(R bb< ) 2 , -NR bb< C(=NR bb< )N(R bb< ) 2 , -C(=O)NR bb< SO 2 R aa< , -NR bb< SO 2 R aa< , -SO 2 N(R bb< ) 2 , -SO 2 R aa< , -SO 2 OR aa< , -OSO 2 R aa< , -S(=O)R aa< , -OS(=O)R aa< , -Si(R aa< ) 3 , -OSi(R aa< ) 3 -C(=S)N(R bb< ) 2 , -C(=O)SR aa< , -C(=S)SR aa< , -SC(=S)SR aa< , -SC(=O)SR aa< . -OC(=O)SR aa< , -SC(=O)OR aa< , -SC(=O)R aa< , -P(=O)(R aa< ) 2 . -P(=O)(OR cc< ) 2 , -OP(=O)(R aa< ) 2 , -OP(=O)(OR cc< ) 2 . -P(=O)(N(R bb< ) 2 ) 2 , -OP(=O)(N(R bb< ) 2 ) 2 , -NR bb< P(=O)(R aa< ) 2 , -NR bb< P(=O)(OR cc< ) 2 , -NR bb< P(=O)(N(R bb< ) 2 ) 2 , -P(R cc< ) 2 , -P(OR cc< ) 2 , -P(R cc< ) 3 +< X -< , -P(OR cc< ) 3 +< X -< , -P(R cc< ) 4 , -P(OR cc< ) 4 , -OP(R cc< ) 2 , -OP(V) 3 +< X -< , -OP(OR cc< ) 2 , -OP(OR cc< ) 3 +< X -< , -OP(R cc< ) 4 , -OP(OR cc< ) 4 , -B(R aa< ) 2 , -B(OR cc< ) 2 , -BR aa< (OR cc< ), C 1-10 alkyl, C 1-10 perhaloalkyl, C 2-10 alkenyl, C 2-10 alkynyl, heteroC 1-10 alkyl, heteroC 2-10 alkenyl, heteroC 2-10 alkynyl, C 3-10 carbocyclyl, 3-14 membered heterocyclyl, C 6-14 aryl, and 5-14 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd< groups; wherein X is a counterion; or two geminal hydrogens on a carbon atom are replaced with the group =O, =S, =NN(R bb< ) 2 , =NNR bb< C(=O)R aa< , =NNR bb< C(=O)OR aa< , =NNR bb< S(=O) 2 R aa< , =NR bb< , or =NOR cc< ; each instance of R aa< is, independently, selected from C 1-10 alkyl, C 1-10 perhaloalkyl, C 2-10 alkenyl, C 2-10 alkynyl, heteroC 1-10 alkyl, heteroC 2-10 alkenyl, heteroC 2-10 alkynyl, C 3-10 carbocyclyl, 3-14 membered heterocyclyl, C 6-14 aryl, and 5-14 membered heteroaryl, or two R aa< groups are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd< groups; each instance of R bb< is, independently, selected from hydrogen, -OH, -OR aa< , -N(R cc< ) 2 , -CN, -C(=O)R aa< , -C(=O)N(R cc< ) 2 , -CO 2 R aa< , -SO 2 R aa< , -C(=NR cc< )OR aa< , -C(=NR cc< )N(R cc< ) 2 , -SO 2 N(R cc< ) 2 , -SO 2 R cc< , -SO 2 OR cc< , -SOR aa< , -C(=S)N(R cc< ) 2 , -C(=O)SR cc< , -C(=S)SR cc< , -P(=O)(R aa< ) 2 , -P(=O)(OR cc< ) 2 , -P(=O)(N(R cc< ) 2 ) 2 , C 1-10 alkyl, C 1-10 perhaloalkyl, C 2-10 alkenyl, C 2-10 alkynyl, heteroC 1-10 alkyl, heteroC 2-10 alkenyl, heteroC 2-10 alkynyl, C 3-10 carbocyclyl, 3-14 membered heterocyclyl, C 6-14 aryl, and 5-14 membered heteroaryl, or two R bb< groups are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd< groups; wherein X -< is a counterion; each instance of R cc< is, independently, selected from hydrogen, C 1-10 alkyl, C 1-10 perhaloalkyl, C 2-10 alkenyl, C 2-10 alkynyl, heteroC 1-10 alkyl, heteroC 2-10 alkenyl, heteroC 2-10 alkynyl, C 3-10 carbocyclyl, 3-14 membered heterocyclyl, C 6-14 aryl, and 5-14 membered heteroaryl, or two R cc< groups are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd< groups; each instance of R dd< is, independently, selected from halogen, -CN, -NO 2 , -N 3 , -SO 2 H, -SO 3 H, -OH, -OR ee< , -ON(R ff< ) 2 , -N(R ff< ) 2 , -N(R ff< ) 3 +< X -< , -N(OR ee< )R ff< , -SH, -SR ee< , -SSR ee< , -C(=O)R ee< , -CO 2 H, -CO 2 R ee< , -OC(=O)R ee< , -OCO 2 R ee< , -C(=O)N(R ff< ) 2 , -OC(=O)N(R ff< ) 2 , -NR ff< C(=O)R ee< , -NR 11< CO 2 R ee< , -NR ff< C(=O)N(R ff< ) 2 , -C(=NR ff< )OR cc< , -OC(=NR ff< )R ee< , -OC(=NR ff< )OR ee< , -C(=NR ff< )N(R ff< ) 2 , -OC(=NR ff< )N(R ff< ) 2 , -NR ff< C(-NR ff< )N(R ff< ) 2 , -NR ff< SO 2 R ee< , -SO 2 N(R ff< ) 2 , -SO 2 R ee< , -SO 2 OR 22< , -OSO 2 R ee< . -S(=O)R ee< , -Si(R ee< ) 3 , -OSi(R ee< ) 3 , -C(=S)N(R ff< ) 2 , -C(-O)SR ee< , -C(=S)SR ee< , -SC(=S)SR ee< , -P(=O)(OR ee< ) 2 , -P(=O)(R ee< ) 2 , -OP(=O)(R ee< ) 2 , -OP(=O)(OR ee< ) 2 , C 1-6 alkyl, C 1-6 perhaloalkyl, C 2-6 alkenyl, C 2-6 alkynyl, heteroC 1-6 alkyl, heteroC 2-6 alkenyl, heteroC 2-6 alkynyl, C 3-10 carbocyclyl, 3-10 membered heterocyclyl, C 6-10 aryl, 5-10 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R gg< groups, or two geminal R dd< substituents can be joined to form =O or =S; wherein X -< is a counterion; each instance of R ee< is, independently, selected from C 1-6 alkyl, C 1-6 perhaloalkyl, C 2-6 alkenyl, C 2-6 alkynyl, heteroC 1-6 alkyl, heteroC 2-6 alkenyl, heteroC 2-6 alkynyl, C 3-10 carbocyclyl, C 6-10 aryl, 3-10 membered heterocyclyl, and 3-10 membered heteroaryl, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R gg< groups; each instance of R ff< is, independently, selected from hydrogen, C 1-6 alkyl, C 1-6 perhaloalkyl, C 2-6 alkenyl, C 2-6 alkynyl, heteroC 1-6 alkyl, heteroC 2-6 alkenyl, heteroC 2-6 alkynyl, C 3-10 carbocyclyl, 3-10 membered heterocyclyl, C 6-10 aryl and 5-10 membered heteroaryl, or two R ff< groups are joined to form a 3-10 membered heterocyclyl or 5-10 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R gg< groups; and each instance of R gg< is, independently, halogen, -CN, -NO 2 , -N 3 , -SO 2 H, -SO 3 H, -OH, -OC 1-6 alkyl, -ON(C 1-6 alkyl) 2 , -N(C 1-6 alkyl) 2 , -N(C 1-6 alkyl) 3 +< X -< , -NH(C 1-6 alkyl) 2 +< X -< , -NH 2 (C 1-6 alkyl) +< X -< , -NH 3 +< X -< , -N(OC 1-6 alkyl)(C 1-6 alkyl), -N(OH)(C 1-6 alkyl), -NH(OH), -SH, -SC 1-6 alkyl, -SS(C 1-6 alkyl), -C(=O)(C 1-6 alkyl), -CO 2 H, -CO 2 (C 1-6 alkyl), -OC(=O)(C 1-6 alkyl), -OCO 2 (C 1-6 alkyl), -C(=O)NH 2 , -C(=O)N(C 1-6 alkyl) 2 , -OC(=O)NH(C 1-6 alkyl), -NHC(=O)( C 1-6 alkyl), -N(C 1-6 alkyl)C(=O)( C 1-6 alkyl), -NHCO 2 (C 1-6 alkyl), -NHC(=O)N(C 1-6 alkyl) 2 , -NHC(=O)NH(C 1-6 alkyl), -NHC(=O)NH 2 , -C(=NH)O(C 1-6 alkyl), -OC(=NH)(C 1-6 alkyl), -OC(-NH)OC 1-6 alkyl, -C(=NH)N(C 1-6 alkyl) 2 , -C(=NH)NH(C 1-6 alkyl), -C(=NH)NH 2 , -OC(=NH)N(C 1-6 alkyl) 2 , -OC(NH)NH(C 1-6 alkyl), -OC(NH)NH 2 , -NHC(NH)N(C 1-6 alkyl) 2 , -NHC(=NH)NH 2 , -NHSO 2 (C 1-6 alkyl), -SO 2 N(C 1-6 alkyl) 2 , -SO 2 NH(C 1-6 alkyl), -SO 2 NH 2 , -SO 3 C 1-6 alkyl, -SO 2 OC 1-6 alkyl, -OSO 2 C 1-6 alkyl, -SOC 1-6 alkyl, -Si(C 1-6 alkyl) 3 , -OSi(C 1-6 alkyl) 3 -C(=S)N(C 1-6 alkyl) 2 , C(=S)NH(C 1-6 alkyl), C(=S)NH 2 , -C(=O)S(C 1-6 alkyl), -C(=S)SC 1-6 alkyl, -SC(=S)SC 1-6 alkyl, -P(=O)(OC 1-6 alkyl) 2 , -P(=O)(C 1-6 alkyl) 2 , -OP(=O)(C 1-6 alkyl) 2 , -OP(=O)(OC 1-6 alkyl) 2 , C 1-6 alkyl, C 1-6 perhaloalkyl, C 2-6 alkenyl, C 2-6 alkynyl, heteroC 1-6 alkyl, heteroC 2-6 alkenyl, heteroC 2-6 alkynyl, C 3-10 carbocyclyl, C 6-10 aryl, 3-10 membered heterocyclyl, 5-10 membered heteroaryl; or two geminal R gg< substituents can be joined to form =O or =S; wherein X -< is a counterion.

[0352] The term "halo" or "halogen" refers to fluorine (fluoro, -F), chlorine (chloro. -Cl). bromine (bromo, -Br), or iodine (iodo, -I).

[0353] The term "hydroxyl" or "hydroxy" refers to the group -OH. The term "substituted hydroxyl" or "substituted hydroxyl," by extension, refers to a hydroxyl group wherein the oxygen atom directly attached to the parent molecule is substituted with a group other than hydrogen, and includes groups selected from -OR aa< , -ON(R bb< ) 2 , -OC(=O)SR aa< , -OC(=O)R aa< , -OCO 2 R aa< , -OC(=O)N(R bb< ) 2 , -OC(=NR bb< )R aa< , -OC(=NR bb< )OR aa< , -OC(=NR bb< )N(R bb< ) 2 , -OS(=O)R aa< , -OSO 2 R aa< , -OSi(R aa< ) 3 , -OP(R cc< ) 2 , -OP(R aa< ) 3 +< X -< , -OP(OR cc< ) 2 , -OP(OR cc< ) 3 +< X -< , -OP(=O)(R aa< ) 2 , -OP(=O)(OR cc< ) 2 , and -OP(=O)(N(R bb< )) 2 , wherein X -< , R aa< , R bb< , and R cc< are as defined herein.

[0354] The term "amino" refers to the group -NH 2 . The term "substituted amino," by extension, refers to a monosubstituted amino, a disubstituted amino, or a trisubstituted amino. In certain embodiments, the "substituted amino" is a monosubstituted amino or a disubstituted amino group.

[0355] The term "monosubstituted amino" refers to an amino group wherein the nitrogen atom directly attached to the parent molecule is substituted with one hydrogen and one group other than hydrogen, and includes groups selected from -NH(R bb< ), -NHC(=O)R aa< , -NHCO 2 R aa< , -NHC(O)N(R bb< ) 2 , -NHC(=NR bb< )N(R bb< ) 2 , -NHSO 2 R aa< , -NHP(=O)(OR cc< ) 2 , and -NHP(=O)(N(R bb< ) 2 ) 2 , wherein R aa< , R bb< and R cc< are as defined herein, and wherein R bb< of the group -NH(R bb< ) is not hydrogen.

[0356] The term "disubstituted amino" refers to an amino group wherein the nitrogen atom directly attached to the parent molecule is substituted with two groups other than hydrogen, and includes groups selected from -N(R bb< ) 2 , -NR bb< C(=O)R aa< , -NR bb< CO 2 R aa< , -NR bb< C(=O)N(R bb< ) 2 , -NR bb< C(=NR bb< )N(R bb< ) 2 , -NR bb< SO 2 R aa< , -NR bb< P(=O)(OR cc< ) 2 , and -NR bb< P(=O)(N(R bb< ) 2 ) 2 , wherein R aa< , R bb< , and R cc< are as defined herein, with the proviso that the nitrogen atom directly attached to the parent molecule is not substituted with hydrogen.

[0357] The term "trisubstituted amino" refers to an amino group wherein the nitrogen atom directly attached to the parent molecule is substituted with three groups, and includes groups selected from -N(R bb< ) 3 and -N(R bb< ) 3 +< X -< , wherein R bb< and X -< are as defined herein.

[0358] The term "sulfonyl" refers to a group selected from -SO 2 N(R bb< ) 2 , -SO 2 R aa< , and - SO 2 OR aa< , wherein R aa< and R bb< are as defined herein.

[0359] The term "sulfinyl" refers to the group -S(=O)R aa< , wherein R aa< is as defined herein.

[0360] The term "acyl" refers to a group having the general formula -C(=O)R XI< , -C(=O)OR XI< , -C(=O)-O-C(=O)R XI< , -C(=O)SR XI< , -C(=O)N(R XI< ) 2 , -C(=S)R XI< , -C(=S)N(R XI< ) 2 , and -C(=S)S(R XI< ), -C(=NR XI< )R XI< , -C(=NR XI< )OR XI< , -C(=NR XI< )SR XI< , and -C(=NR XI< )N(R XI< ) 2 , wherein R XI< is hydrogen; halogen; substituted or unsubstituted hydroxyl; substituted or unsubstituted thiol; substituted or unsubstituted amino; substituted or unsubstituted acyl, cyclic or acyclic, substituted or unsubstituted, branched or unbranched aliphatic; cyclic or acyclic, substituted or unsubstituted, branched or unbranched heteroaliphatic; cyclic or acyclic, substituted or unsubstituted, branched or unbranched alkyl; cyclic or acyclic, substituted or unsubstituted, branched or unbranched alkenyl; substituted or unsubstituted alkynyl; substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, aliphaticoxy, heteroaliphaticoxy, alkyloxy, heteroalkyloxy, aryloxy, heteroaryloxy, aliphaticthioxy, heteroaliphaticthioxy, alkylthioxy, heteroalkylthioxy, arylthioxy, heteroarylthioxy, mono- or di- aliphaticamino, mono- or di- heteroaliphaticamino, mono- or di- alkylamino, mono- or di- heteroalkylamino, mono- or di-arylamino, or mono- or di-heteroarylamino; or two R XI< groups taken together form a 5- to 6-membered heterocyclic ring. Exemplary acyl groups include aldehydes (-CHO), carboxylic acids (-CO 2 H), ketones, acyl halides, esters, amides, imines, carbonates, carbamates, and ureas. Acyl substituents include, but are not limited to, any of the substituents described herein, that result in the formation of a stable moiety (e.g., aliphatic, alkyl, alkenyl, alkynyl, heteroaliphatic, heterocyclic, aryl, heteroaryl, acyl, oxo, imino, thiooxo, cyano, isocyano, amino, azido, nitro, hydroxyl, thiol, halo, aliphaticamino, heteroaliphaticamino, alkylamino, heteroalkylamino, arylamino, heteroarylamino, alkylaryl, arylalkyl, aliphaticoxy, heteroaliphaticoxy, alkyloxy. heteroalkyloxy, aryloxy, heteroaryloxy, aliphaticthioxy, heteroaliphaticthioxy, alkylthioxy, heteroalkylthioxy, arylthioxy, heteroarylthioxy, acyloxy, and the like, each of which may or may not be further substituted).

[0361] The term "carbonyl" refers a group wherein the carbon directly attached to the parent molecule is sp 2< hybridized, and is substituted with an oxygen, nitrogen or sulfur atom, e.g., a group selected from ketones (-C(=O)R aa< ), carboxylic acids (-CO 2 H), aldehydes (-CHO), esters (-CO 2 R aa< , -C(=O)SR aa< , -C(=S)SR aa< ), amides (-C(=O)N(R bb< ) 2 , -C(=O)NR bb< SO 2 R aa< , -C(=S)N(R b< ) 2 ), and imines (-C(=NR bb< )R aa< , -C(=NR bb< )OR aa< ), -C(=NR bb< )N(R bb< ) 2 ), wherein R aa< and R bb< are as defined herein.

[0362] Nitrogen atoms can be substituted or unsubstituted as valency permits, and include primary, secondary, tertiary, and quaternary nitrogen atoms. Exemplary nitrogen atom substituents include, but are not limited to, hydrogen, -OH, -OR aa< , -N(R cc< ) 2 . -CN, -C(=O)R aa< , -C(=O)N(R cc< ) 2 , -CO 2 R aa< , -SO 2 R aa< , -C(=NR bb< )R aa< , -C(=NR cc< )OR aa< , -C(=NR cc< )N(R cc< ) 2 , -SO 2 N(R cc< ) 2 , -SO 3 R cc< , -SO 2 OR cc< , -SOR aa< , -C(-S)N(R cc< ) 2 , -C(=O)SR cc< , -C(=S)SR cc< , -P(=O)(OR cc< ) 2 , -P(=O)(R aa< ) 2 , -P(=O)(N(R cc< ) 2 ) 2 , C 1-10 alkyl, C 1-10 perhaloalkyl, C 2-10 alkenyl, C 2-10 alkynyl, heteroC 1-10 alkyl, heteroC 2-10 alkenyl, heteroC 2-10 alkynyl, C 3-10 carbocyclyl, 3-14 membered heterocyclyl, C 6-14 aryl, and 5-14 membered heteroaryl, or two R cc< groups attached to an N atom are joined to form a 3-14 membered heterocyclyl or 5-14 membered heteroaryl ring, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd< groups, and wherein R aa< , R bb< , R cc< and R dd< arc as defined above.

[0363] In certain embodiments, the substituent present on the nitrogen atom is an nitrogen protecting group (also referred to herein as an "amino protecting group"). Nitrogen protecting groups include, but are not limited to, -OH, -OR aa< , -N(R cc< ) 2 , -C(=O)R aa< , -C(=O)N(R cc< ) 2 , -CO 2 R aa< , -SO 2 R aa< , -C(=NR cc< )R aa< , -C(-NR cc< )OR aa< , -C(-NR cc< )N(R cc< ) 2 , -SO 2 N(R cc< ) 2 , -SO 2 R cc< , -SO 2 OR cc< , -SOR aa< , -C(=S)N(R cc< ) 2 , -C(=O)SR cc< , -C(=S)SR cc< , C 1-10 alkyl (e.g., aralkyl, heteroaralkyl), C 2-10 alkenyl, C 2-10 alkynyl, heteroC 1-10 alkyl, heteroC 2-10 alkenyl, heteroC 2-10 alkynyl, C 3-10 carbocyclyl, 3-14 membered heterocyclyl, C 6-14 aryl, and 5-14 membered heteroaryl groups, wherein each alkyl, alkenyl, alkynyl, heteroalkyl, heteroalkenyl, heteroalkynyl, carbocyclyl, heterocyclyl, aralkyl, aryl, and heteroaryl is independently substituted with 0, 1, 2, 3, 4, or 5 R dd< groups, and wherein R aa< , R bb< , R cc< and R dd< are as defined herein. Nitrogen protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rd edition, John Wiley & Sons, 1999.

[0364] For example, nitrogen protecting groups such as amide groups (e.g., -C(=O)R aa< ) include, but are not limited to, formamide, acetamide, chloroacetamide, trichloroacetamide, trifluoroacetamide, phenylacetamide, 3-phenylpropanamide, picolinamide, 3-pyridylcarboxamide, N-benzoylphenylalanyl derivative, benzamide, p-phenylbenzamide, o-nitophenylacetamide, o-nitrophenoxyacetamide, acetoacetamide, (N'-dithiobenzyloxyacylamino)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 and o-(benzoyloxymethyl)benzam ide.

[0365] Nitrogen protecting groups such as carbamate groups (e.g., -C(=O)OR aa< ) include, but are not limited to, 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-10,10,10,10-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)-1-methylethyl carbamate (Adpoc), 1,1-dimethyl-2-haloethyl carbamate, 1,1-dimethyl-2,2-dibromoethyl carbamate (DB-t-BOC), 1,1-dimethyl-2,2,2-trichloroethyl carbamate (TCBOC), 1-methyl-t-(4-biphenylyl)ethyl carbamate (Bpoc), 1-(3,5-di-t-butylphenyl)-1-methylethyl carbamate (t-Bumeoc), 2-(2'- and 4'-pyridyl)ethyl carbamate (Pyoc), 2-(N,N-dicyclohexylcarboxamido)ethyl carbamate, t-butyl carbamate (BOC or 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-(1,3-dithianyl)]methyl carbamate (Dmoc), 4-methylthiophenyl carbamate (Mtpc), 2,4-dimethylthiophenyl carbamate (Bmpc), 2-phosphonioethyl carbamate (Peoc), 2-triphenylphosphonioisopropyl carbamate (Ppoc), 1,1-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 carbamate, o-nitrobenzyl carbamate, 3,4-dimethoxy-6-nitrobenzyl carbamate, phenyl(o-nitrophenyl)methyl carbamate, t-amyl carbamate, S-benzyl thiocarbamate, p-cyanobenzyl carbamate, cyclobutyl carbamate, cyclohexyl carbamate, cyclopentyl carbamate, cyclopropylmethyl carbamate, p-decyloxybcnzyl carbamate, 2,2-dimethoxyacylvinyl carbamate, o-(N,N-dimethylcarboxamido)benzyl carbamate, 1,1-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, 1-methyl-1-(3,5-dimethoxyphenyl)ethyl carbamate, 1-methyl-1-(p-phenylazophenyl)ethyl carbamate, 1-methyl-1-phenylethyl carbamate, 1-methyl-1-(4-pyridyl)ethyl carbamate, phenyl carbamate, p-(phenylazo)benzyl carbamate, 2,4,6-tri-t-butylphenyl carbamate, 4-(trimethylammonium)benzyl carbamate, and 2,4,6-trimethylbenzyl carbamate.

[0366] Nitrogen protecting groups such as sulfonamide groups (e.g., -S(=O) 2 R aa< ) include, but are not limited to, p-toluenesulfonamide (Ts), benzenesulfonamide, 2,3,6-trimethyl-4-methoxybenzenesulfonamide (Mtr), 2,4,6-trimethoxybenzenesulfonamide (Mtb), 2,6-dimethyl-4-methoxybenzenesulfonamide (Pme), 2,3,5,6-tetramethyl-4-methoxybenzenesulfonamide (Mte), 4-methoxybenzenesulfonamide (Mbs), 2,4,6-trimethylbenzenesulfonamide (Mts), 2,6-dimethoxy-4-methylbenzenesulfonamide (iMds), 2,2,5,7,8-pentamethylchroman-6-sulfonamide (Pmc), methanesulfonamide (Ms), β-trimethylsilylethanesulfonamide (SES), 9-anthracenesulfonamide, 4-(4',8'-dimethoxynaphthylmethyl)benzenesulfonamide (DNMBS), benzylsulfonamide, trifluoromethylsulfonamide, and phenacylsulfonamide.

[0367] Other nitrogen protecting groups include, but are not limited to, phenothiazinyl-(10)-acyl derivative, N'-p-toluenesulfonylaminoacyl derivative, N'-phenylaminothioacyl derivative, N-benzoylphenylalanyl derivative, N-acetylmethionine derivative, 4,5-diphenyl-3-oxazolin-2-one, N-phthalimide, N-dithiasuccinimide (Dts), N-2,3-diphenylmaleimidc, 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 1,3-dibenzyl-1,3,5-triazacyclohexan-2-one, 1-substituted 3,5-dinitro-4-pyridone, N-methylamine, N-allylamine, N-[2-(trimethylsilyl)ethoxy]methylamine (SEM), N-3-acetoxypropylamine, N-(1-isopropyl-4-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 (Fcm), 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-dimethyl-3-oxo-1-cyclohexenyl)amine, N-borane derivative, N-diphenylborinic acid derivative, N-[phenyl(pentaacylchromium- or tungsten)acyl]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-dinitrobenzenesulfenamide, pentachlorobenzenesulfenamide, 2-nitro-4-methoxybenzenesulfenamide, triphenylmethylsulfenamide, and 3-nitropyridinesulfenamide (Npys).

[0368] In certain embodiments, the substituent present on an oxygen atom is an oxygen protecting group (also referred to herein as an "hydroxyl protecting group"). Oxygen protecting groups include, but are not limited to, -R aa< , -N(R bb< ) 2 , -C(=O)SR aa< , -C(=O)R aa< , -CO 2 R aa< , -C(=O)N(R bb< ) 2 , -C(=NR bb< )R aa< , -C(=NR bb< )OR aa< , -C(=NR bb< )N(R bb< ) 2 , -S(=O)R ee< , -SO 2 R aa< , -Si(R aa< ) 3 , -P(R cc< ) 2 , -P(R cc< )3 +< X -< , -P(OR cc< ) 2 , -P(OR cc< ) 3 +< X -< , -P(=O)(R aa< ) 2 , -P(=O)(OR cc< ) 2 , and -P(=O)(N(R bb< ) 2 ) 2 , wherein X -< , R aa< , R bb< , and R cc< are as defined herein. Oxygen protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rd edition, John Wiley & Sons, 1999.

[0369] Exemplary oxygen protecting groups include, but are not limited to, methyl, methoxylmethyl (MOM), methylthiomethyl (MTM), t-butylthiomethyl, (phenyldimethylsilyl)methoxymethyl (SMOM), benzyloxymethyl (BOM), p-methoxybenzyloxymcthyl (PMBM), (4-methoxyphenoxy)methyl (p-AOM), guaiacolmelhyl (GUM), t-butoxymcthyl, 4-pentenyloxymethyl (POM), siloxymethyl, 2-methoxyethoxymethyl (MEM), 2,2,2-trichloroethoxymethyl, bis(2-chloroethoxy)melhyl, 2-(trimethylsilyl)ethoxymethyl (SEMOR), tetrahydropyranyl (THP), 3 bromotetrahydropyranyl, tetrahydrothiopyranyl, 1-methoxycyclohexyl, 4-methoxytetrahydropyranyl (MTHP), 4-methoxytetrahydrothiopyranyl, 4-methoxytetrahydrothiopyranyl S,S-dioxide, 1-[(2-chloro-4-methyl)phenyl]-4-methoxypiperidin-4-yl (CTMP), 1,4-dioxan-2-yl, tetrahydrofuranyl, tetrahydrothiofuranyl, 2,3,3a,4,5,6,7,7a-octahydro-7,8,8-trimethyl-4,7-methanobenzofuran-2-yl, 1-ethoxyethyl. 1-(2-chloroethoxy)ethyl, 1-methyl-1-methoxyethyl, 1-methyl-1-benzyloxyethyl, 1-methyl-1-benzyloxy-2-fluoroethyl, 2,2,2-trichloroethyl, 2-trimethylsilylethyl, 2-(phenylselenyl)ethyl, t-butyl, allyl, p-chlorophenyl, p-methoxyphenyl, 2,4-dinitrophenyl, benzyl (Bn), 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, α-naphthyldiphcnylmethyl, p-methoxyphenyldiphenylmethyl, 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-1-yl)bis(4',4"-dimethoxyphenyl)methyl, 1,1-bis(4-methoxyphenyl)-1'-pyrenylmethyl, 9-anthryl, 9-(9-phenyl)xanthenyl, 9-(9-phenyl-10-oxo)anthryl, 1,3-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), methyl carbonate, 9-fluorenylmethyl carbonate (Fmoc), ethyl carbonate, 2,2,2-trichloroethyl carbonate (Troc), 2-(trimethylsilyl)ethyl carbonate (TMSEC), 2-(phenylsulfonyl) ethyl carbonate (Psec), 2-(triphenylphosphonio) ethyl carbonate (Peoc), isobutyl carbonate, vinyl carbonate, allyl carbonate, t-butyl carbonate (BOC or Boc), p-nitrophenyl carbonate, benzyl carbonate, p-methoxybenzyl carbonate, 3,4-dimethoxybenzyl carbonate, o-nitrobenzyl carbonate, p-nitrobenzyl carbonate, S-benzyl thiocarbonate, 4-ethoxy-1-napththyl carbonate, methyl dithiocarbonate, 2-iodobenzoate, 4-azidobutyrate, 4-nitro-4-methylpentanoate, o-(dibromomethyl)benzoate, 2-formylbenzenesulfonate, 2-(methylthiomcthoxy)ethyl, 4-(methylthiomethoxy)butyrate, 2-(methylthiomethoxymethyl)benzoate, 2,6-dichloro-4-methylphenoxyacetate, 2,6-dichloro-4-(1,1,3,3-tetramethylbutyl)phenoxyacetate, 2,4-bis(1,1-dimethylpropyl)phenoxyacetate, chlorodiphenylacetate, isobutyrate, monosuccinoate, (E)-2-methyl-2-butenoate, o-(methoxyacyl)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).

[0370] In certain embodiments, the substituent present on a sulfur atom is a sulfur protecting group (also referred to as a "thiol protecting group"). Sulfur protecting groups include, but are not limited to, -R aa< , -N(R bb< ) 2 , -C(=O)SR aa< , -C(=O)R aa< , -CO 2 R aa< , -C(=O)N(R bb< ) 2 , -C(=NR bb< )R aa< , -C(=NR bb< )OR aa< , -C(=NR bb< )N(R bb< ) 2 , -S(=O)R ee< , -SO 2 R aa< , -Si(R aa< ) 3 , -P(R cc< ) 2 , -P(R cc< ) 3 +< X -< , -P(OR cc< ) 2 , -P(OR cc< ) 3 +< X -< , -P(=O)(R aa< ) 2 , -P(=O)(OR cc< ) 2 , and -P(=O)(N(R bb< ) 2 ) 2 , wherein R aa< , R bb< , and R cc< are as defined herein. Sulfur protecting groups are well known in the art and include those described in detail in Protecting Groups in Organic Synthesis, T. W. Greene and P. G. M. Wuts, 3rd edition, John Wiley & Sons, 1999.

[0371] A "counterion" or "anionic counterion" is a negatively charged group associated with a positively charged group in order to maintain electronic neutrality. An anionic counterion may be monovalent (i.e., including one formal negative charge). An anionic counterion may also be multivalent (i.e., including more than one formal negative charge), such as divalent or trivalent. Exemplary counterions include halide ions (e.g., F -< , Cl -< , Br -< , I -< ), NO 3 -< , ClO 4 -< , OH -< , H 2 PO 4 -< , HCO 3 -< , HSO 4 -< , sulfonate ions (e.g., methansulfonate, trifluoromethanesulfonate, p-toluenesulfonate, benzenesulfonate, 10-camphor sulfonate, naphthalene-2-sulfonate, naphthalene-1-sulfonic acid-5-sulfonate, ethan-1-sulfonic acid-2-sulfonate, and the like), carboxylate ions (e.g., acetate, propanoate, benzoate, glycerate, lactate, tartrate, glycolate, gluconate, and the like), BF 4 -< , PF 4 -< , PF 6 -< , AsF 6 -< , SbF 6 -< , B[3,5-(CF 3 ) 2 C 6 H 3 ] 4 ] -< , B(C 6 F 5 ) 4 -< , BPh 4 -< , Al(OC(CF 3 ) 3 ) 4 -< , and carborane anions (e.g., CB 11 H 12 -< or (HCB 11 Me 5 Br 6 ) -< ). Exemplary counterions which may be multivalent include CO 3 2-< , HPO 4 2-< , PO 4 3-< , B 4 O 7 2-< , SO 4 2-< , S 2 O 3 2-< , carboxylate anions (e.g., tartrate, citrate, fumarate, maleate, malate, malonate, gluconate, succinate, glutarate, adipate, pimelate, suberate, azelate, sebacate, salicylate, phthalates, aspartate, glutamate, and the like), and carboranes.

[0372] As used herein, use of the phrase "at least one instance" refers to 1, 2, 3, 4, or more instances, but also encompasses a range, e.g., for example, from 1 to 4, from 1 to 3, from 1 to 2, from 2 to 4, from 2 to 3. or from 3 to 4 instances, inclusive.

[0373] These and other exemplary substituents are described in more detail throughout. The invention is not intended to be limited in any manner by the above exemplary listing of substituents.

[0374] As used herein, the term "salt" refers to any and all salts, and encompasses pharmaceutically acceptable salts.

[0375] The term "pharmaceutically acceptable salt" refers to those 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 arc commensurate with a reasonable benefit / risk ratio. Pharmaceutically acceptable salts arc well known in the art. For example, Berge et al. describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 1977, 66, 1-19. Pharmaceutically acceptable salts of the compounds of this invention include those derived from suitable inorganic and organic acids and bases. Examples of pharmaceutically acceptable, nontoxic acid addition salts 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, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, or malonic acid or by using other methods known in the art such as ion exchange. Other pharmaceutically acceptable salts include 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. Salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium, and N +< (C 1-4 alkyl) 4 -< salts. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, lower alkyl sulfonate, and aryl sulfonate.Biologically Active Agents

[0376] This disclosure contemplates that the LNPs provided herein and / or the various combination therapies provided herein may be used to deliver a variety of agents to a subject. Such agents typically will be biologically active agents. Biologically active agents arc agents that have an effect in vivo, and preferably a beneficial effect, such as desirable immune modulation, immune stimulation, immune inhibition, cell killing, cell preservation, modified gene expression, protein replacement, and the like. Biologically active agents include but are not limited to prophylactic agents, therapeutic agents, and diagnostic agents. Biologically active agents include immunomodulatory agents such as immunostimulatory or immunoinhibitory agents, antigens, antibodies and antibody fragments such as antigen-binding antibody fragments, adjuvants, cytokines such as interleukins, anti-bacterial agents, anti-viral agents, anti-fungal agents, anti-parasitic agents, anti-cancer agents, antiinflammatory agents, and the like.

[0377] Such agents may be, without limitation, nucleic acids, proteins or peptide, small organic compounds, carbohydrates and / or polysaccharides, and the like. They may be used to express nucleic acids and / or proteins in cells, particularly in cells that are deficient in such nucleic acids or proteins or have mutated versions of such nucleic acids or proteins. They may be used to introduce and express nucleic acids or proteins that are not native to the cell or organism, as may be done for example in the context of an immunization or vaccination protocol. In this respect, the nucleic acid or protein may be foreign to the subject to whom it is administered (e.g., not naturally occurring in such subject, or not naturally occurring at all), and it is administered to the subject to induce and / or boost an immune response to such nucleic acid or protein. The nucleic acids provided herein may be used for such a purpose.

[0378] Other biologically active agents may be used alone or together with such nucleic acids or proteins, including formulated together with such nucleic acids or proteins, including formulated in the LNPs of this disclosure.Nucleic Acids

[0379] As used herein, the term "nucleic acid" refers to a compound comprising a nucleobase and an acidic moiety, e.g., a nucleoside, a nucleotide, or a polymer of nucleotides. Typically, polymeric nucleic acids, e.g.. nucleic acid molecules comprising three or more nucleotides are linear molecules, in which adjacent nucleotides are linked to each other via a phosphodiester linkage. In some embodiments, "nucleic acid" refers to individual nucleic acid residues (e.g., nucleotides and / or nucleosides). In some embodiments, "nucleic acid" refers to an oligonucleotide chain comprising three or more individual nucleotide residues. As used herein, the terms "oligonucleotide" and "polynucleotide" can be used interchangeably to refer to a polymer of nucleotides (e.g., a string of at least three nucleotides). In some embodiments, "nucleic acid" encompasses RNA as well as single and / or double-stranded DNA. A nucleic acid sequence is presented in the 5' to 3' direction unless otherwise indicated.

[0380] Nucleic acids include any compound and / or substance that comprises a polymer of nucleotides. These polymers are referred to as polynucleotides. Nucleic acids may be or may include, for example, ribonucleic acids (RNAs), deoxyribonucleic acids (DNAs), threose nucleic acids (TNAs), glycol nucleic acids (GNAs), peptide nucleic acids (PNAs), locked nucleic acids (LNAs, including LNA having a β- D-ribo configuration, α-LNA having an α-L-ribo configuration (a diastereomer of LNA), 2'-amino-LNA having a 2'-amino functionalization, and 2'-amino- α-LNA having a 2'-amino functionalization), ethylene nucleic acids (ENA), cyclohexenyl nucleic acids (CeNA) or chimeras or combinations thereof.

[0381] Nucleic acids may be naturally occurring, for example, in the context of a genome, a transcript, an mRNA, tRNA, rRNA, siRNA, snRNA, plasmid. cosmid, chromosome, chromatid, or other naturally occurring nucleic acid molecule. On the other hand, a nucleic acid molecule may be a non-naturally occurring molecule, e.g., a recombinant DNA or RNA, an artificial chromosome, an engineered genome, or fragment thereof, or a synthetic DNA, RNA, DNA / RNA hybrid, or including non-naturally occurring nucleotides or nucleosides. Nucleic acids can be purified from natural sources, produced using recombinant expression systems and optionally purified, chemically synthesized, etc.

[0382] Furthermore, the terms "nucleic acid," "DNA," "RNA," and / or similar terms include nucleic acid analogs, i.e., analogs having other than a phosphodiester backbone.

[0383] Where appropriate, e.g., in the case o...

Claims

1. A lipid nanoparticle (LNP) encapsulating an mRNA coding for a therapeutic protein, wherein the LNP comprises a cationic lipid, a helper lipid, a structural lipid, and a stabilizer, wherein the cationic lipid is an ionizable lipid, wherein the stabilizer is a PEG lipid, and wherein the PEG lipid is a compound of Formula (V-OH): or a pharmaceutically acceptable salt thereof, wherein: r is an integer between 1 and 100, inclusive; and R5 is optionally substituted C10-40 alkyl, optionally substituted C10-40 alkenyl, or optionally substituted C10-40 alkynyl; and wherein the LNP does not trigger accelerated blood clearance.

2. The LNP of Claim 1, wherein the ionizable lipid is of the Formula (XI): or a pharmaceutically acceptable salt thereof, wherein: 1 is selected from 1, 2, 3, 4, and 5; M and M' are independently selected from -C(O)O- , -OC(O)-, -C(O)N(R')-, -P(O)(OR')O-, - S-S-, an aryl group, and a heteroaryl group; M1 is a bond or M'; R2 and R3 are independently selected from the group consisting of H, C1-14 alkyl, and C2-14 alkenyl; R4 is unsubstituted C1-3 alkyl, or - (CH2)nQ, in which n is selected from 2, 3, or 4 and Q is OH, -NHC(S)N(R)2, -NHC(O)N(R)2, -N(R)C(O)R, -N(R)S(O)2R, -N(R)R8, -NHC(=NR9)N(R)2, - NHC(=CHR9)N(R)2, -OC(O)N(R)2, -N(R)C(O)OR, heteroaryl or heterocycloalkyl; R' is independently selected from the group consisting of C1-8 alkyl, C2-18 alkenyl, -R∗YR", - YR", and H; R" is independently selected from the group consisting of C3-14 alkyl and C3-14 alkenyl; R∗ is independently selected from the group consisting of C1-12 alkyl and C2-12 alkenyl; and Y is independently a C3-6 carbocycle.

3. The LNP of claim 2, wherein the compound of Formula (XI) has the structure of compound 18: or a pharmaceutically acceptable salt thereof.

4. The LNP of any one of claims 1-3, wherein the compound of Formula (V-OH) is: or a pharmaceutically acceptable salt thereof.

5. The LNP of any one of claims 1-4, wherein the PEG lipid comprises a PEG molecule of an average molecular weight of: (i) 2,000 Da; or (ii) less than 2,000 Da, optionally around 1,500 Da, around 1,000 Da, or around 500 Da.

6. The LNP of any one of claims 1-2, wherein the compound of Formula (V-OH) is HO-PEG2000-ester-C18.

7. The LNP of any one of claims 1-6, wherein the compound of Formula (V-OH) is: or a pharmaceutically acceptable salt thereof.

8. The LNP of any one of claims 1-7, wherein the helper lipid is a non-cationic helper lipid and the structural lipid is cholesterol, and wherein the LNP has a molar ratio of about 45-65% cationic lipid, about 0.15-15% PEG lipid, about 15-45% cholesterol and about 5-25% non-cationic helper lipid.

9. The LNP of claim 8, wherein the LNP comprises less than 0.5 % (w / w) of PEG lipid.

10. The LNP of claim 8, wherein the LNP comprises less than 0.25 % (w / w) of PEG lipid.

11. The LNP of any one of claims 1-7, wherein the helper lipid is: (i) a non-cationic helper lipid comprising at least one fatty acid chain of at least 8C and at least one polar head group moiety; (ii) a zwitterionic non-cationic helper lipid; (iii) a lipid that is not a phosphatidyl choline (PC); or (iv) 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC).

12. The LNP of any one of claims 1-7 or 11, wherein the helper lipid: (i) competitively inhibits phosphatidylcholine from binding to CD36; or (ii) does not bind or has low binding activity to CD36.

13. The LNP of any one of claims 1-7, wherein the structural lipid is a sterol, for example cholesterol.

14. The LNP of anyone of the preceding claims, wherein the mRNA comprises (a) chemically modified bases or sugars, and backbone modifications; and / or (b) a miR binding site, optionally wherein the miR binding site: (i) is selected from miR 126, miR 155 and miR 142 3p; or (ii) comprises a miR-122 binding site and also comprises one or more miR binding sites selected from the group consisting of miR-142, miR-146, miR-155, miR-126, miR-16, miR-21, miR-223, miR-24, miR-27.

15. The LNP of any one of the preceding claims, wherein the LNP is characterized as having reduced binding to B1a cells and / or reduced B1a cell activation activity.

16. A lipid nanoparticle (LNP) for use in a method of delivering a therapeutic level of a protein of interest to a subject, wherein the LNP is the LNP of any one of the preceding claims, wherein the method comprises administering a first dose and a second dose of the LNP to the subject; and wherein the first dose of LNP does not induce an immune response that promotes accelerated blood clearance (ABC) upon administration of a second dose of LNP.

17. The LNP for use of claim 16, wherein the immune response is an anti-PEG IgM or anti-PEG IgG response.

18. The LNP for use of any one of claims 16-17, wherein the first dose of LNP does not activate a CD36-dependent signalling pathway in an immune cell upon administration of a second dose of LNP.

19. The LNP for use of any one of claims 16-18, wherein the interval between the first dose and the second dose is about 21 days or less, and / or wherein the method further comprises administering to the subject an additional agent that inhibits immune responses.