Combination therapy for treating hepatitis b virus (HBV) infection

Abstract

The present disclosure provides methods for treating HBV infection using combination therapies in patients with serum HBsAg levels below 3000 IU / mL prior to treatment. The components of the combination therapies may include one or more of an anti-HBV antibody; an siRNA that targets an HBV mRNA; interferon-α; and a nucleos(t)ide reverse transcriptase inhibitor (NRTI).

Description

Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202COMBINATION THERAPY FOR TREATING HEPATITIS B VIRUS (HBV)INFECTIONREFERENCE TO AN ELECTRONIC SEQUENCE LISTING

[0001] This application contains a Sequence Listing, which has been submitted electronically in xml format and is hereby incorporated by reference in its entirety. Said xml copy, created on November 3, 2025, is named SeqList-368561-45202.xml and is 43,797 bytes in size.BACKGROUND

[0002] Hepatitis B virus (HBV) is a DNA virus that infects, replicates, and persists in human hepatocytes (Protzer U et al., Living in the liver: hepatic infections, Nature Reviews Immunology 2012, 12:201-213). The small viral genome (3.2 kb), consists of partially doublestranded, relaxed-circular DNA (rcDNA) and has 4 open reading frames encoding 7 proteins: HBcAg (HBV core antigen, viral capsid protein), HBeAg (hepatitis B e-antigen), HBV Pol / RT (polymerase, reverse transcriptase), PreSl / PreS2 / HBsAg (large, medium or "middle", and small surface envelope glycoproteins), and HBx (HBV x antigen, regulator of transcription required for the initiation of infection) (Seeger C et al., Molecular biology of hepatitis B virus infection, Virology 2015, 479-480:672-686; Tong et al., Overview of viral replication and genetic variability, Journal of Hepatology 2016, 64(1):S4-S16).

[0003] In hepatocytes, rcDNA, the form of HBV nucleic acid that is introduced by the infection virion, is converted into a covalently closed circular DNA (cccDNA), which persists in the host cell's nucleus as an episomal chromatinized structure (Allweiss L et al., The Role of cccDNA in HBV Maintenance, Viruses 2017, 9: 156). The cccDNA serves as a transcription template for all viral transcripts (Lucifora J et al., Attacking hepatitis B virus cccDNA — The holy grail to hepatitis B cure, Journal of Hepatology 2016, 64(1):S41-S48). Pregenomic RNA (pgRNA) transcripts are reverse transcribed into new rcDNA for new virions, which are secreted without causing cytotoxicity. In addition to infectious virions, infected hepatocytes secrete large amounts of genome-free subviral particles that may exceed the number of secreted virions by 10,000-fold (Seeger et al., 2015, supra). Random integration of the virus into the host 1178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202genome can occur as well, a mechanism that contributes to hepatocyte transformation (Levrero et al., Mechanisms of HBV-induced hepatocellular carcinoma, Journal of Hepatology 2016, 64( 1): S84-S 101). HBV persists in hepatocytes in the form of cccDNA and integrated DNA (intDNA).

[0004] Hepatitis B infection is characterized by serologic viral markers and antibodies. In acute resolving infections, the virus is cleared by effective innate and adaptive immune responses that include cytotoxic T cells leading to death of infected hepatocytes, and induction of B cells producing neutralizing antibodies that prevent the spread of the virus (Bertoletti A, Adaptive immunity in HBV infection, Journal of Hepatology 2016, 64(1):S71-S83; Maini MK et al., The role of innate immunity in the immunopathology and treatment of HBV infection, Journal of Hepatology 2016, 64(l):S60-S70; Li Y et al., Genome-wide association study identifies 8p21.3 associated with persistent hepatitis B virus infection among Chinese, Nature Communications 2016, 7: 11664). In contrast, chronic infection is associated with T and B cell dysfunction, mediated by multiple regulatory mechanisms including presentation of viral epitopes on hepatocytes and secretion of subviral particles (Bertoletti et al., 2016, supra; Maini et al., 2016, supra; Burton AR et al., Dysfunctional surface antigen specific memory B cells accumulate in chronic hepatitis B infection, EASL International Liver Congress, Paris, France 2018). Thus, the continued expression and secretion of viral proteins due to cccDNA persistence in hepatocytes is considered a key step in the inability of the host to clear the infection.

[0005] Chronic HBV infection remains an important global public health problem with significant morbidity and mortality (Trepo C, A brief history of hepatitis milestones, Liver Int. 2014, Feb;34 Suppl 1:29-37). Chronic HBV infection is a dynamic process characterized by the interplay of viral replication and the host immune response. Patients can be divided into different stages of the disease based on the levels of Hepatitis B e antigen (HBeAg), HBV DNA, alanine aminotransferase (ALT), and liver inflammation (European Association for the Study of the Liver, EASL 2017 Clinical Practice Guidelines on the management of hepatitis B virus infection, J Hepatol. 2017 Aug, 67(2):370-398; Sarin SK et al., Asian-Pacific clinical practice guidelines on the management of hepatitis B: a 2015 update, Hepatol Int. 2016 Jan,2178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520210(1): 1-98; TerraultNA et al., Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance, Hepatology 2018 Apr, 67(4): 1560-1599).

[0006] The global prevalence of chronic HBV infection is estimated to be approximately 254 million (Global hepatitis report 2024: action for access in low- and middle-income countries, Geneva: World Health Organization 2024). Chronic HBV infection has been associated with long-term liver outcomes and complications including cirrhosis, liver cancer, liver failure, liver transplantation, and liver-related death, as well as with stigma, discrimination, and reduced quality of life (Younossi ZM, et al., Clin Gastroenterol Hepatol. 2023, 21(8): 1978-91; Varbobitis I and Papatheodoridis GV, Clin Mol Hepatol. 2016, 22:319-26). There continues to be an unmet medical need for further improvement of long-term liver outcomes via sustained off-treatment HBsAg loss (functional cure), which could be achieved using antiviral and immunomodulatory combination therapies (TerraultNA, et al. Hepatology. 2018, 67: 1560-99; European Association for the Study of the Liver (EASL), J Hepatol. 2017, 67:370-98).BRIEF SUMMARY

[0007] In some aspects, the present disclosure relates to methods of treating hepatitis B virus (HBV) infection in a subject having a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the methods comprising administering to the subject an antibody and a small interfering RNA molecule (siRNA), wherein:(a) the antibody comprises the light chain amino acid sequence:SYELTQPPSVSVSPGQTVSIPCSGDKLGNKNVAWFQHKPGQSPVLVIYEVKYRP SGIPERFSGSNSGNTATLTISGTQAMDEAAYFCQTFDSTTVVFGGGTRLTVLGQ PKAAPSVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADSSPVKAGVETT TPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS (SEQ ID NO: 19)3178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202and the heavy chain amino acid sequence:ELQLVESGGGWVQPGGSQRLSCAASGRIFRSFYMSWVRQAPGKGLEWVATIN QDGSEKLYVDSVKGRFTISRDNAKNSLFLQMNNLRVEDTAVYYCAAWSGNSG GMDVWGQGTTVSVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNT KVDKKVEPKSCDKTHTCPPCPAPELLAGPSVFLFPPKPKDTLMISRTPEVTCVV VDVSHEDPEVI<FNWYVDGVEVHNAI<TI<PREEQYNSTYRVVSVLTVLHQDWL NGKEYKCKVSNKALPLPEEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVLHEALHSHYTQKSLSLSPGK (SEQ ID NO: 18); and(b) the siRNA comprises a sense strand and an antisense strand, wherein the sense strand comprises: 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO: 5) attached to a ligand (L) at the 3' end, and the antisense strand comprises: 5'-usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO: 6),wherein a, c, g, and u are 2'-O-methyladenosine-3 '-phosphate, 2'-O-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-O-methyluridine-3 '-phosphate, respectively;Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;(Agn) is adenosine-glycol nucleic acid (GNA);s is a phosphorothioate linkage; andL is178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202

[0008] In some aspects, the present disclosure relates to compositions for use in such methods, as well as uses of the compositions in the manufacture of medicaments for use in the methods.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 shows the study design for the clinical study in Example 1. Study drugs were administered as follows: tobevibart 300 mg Q4W, elebsiran 200 mg Q4W, and PEG-IFNa 180 pg QW. AE, adverse event; ALT, alanine transaminase; EOT, end of treatment; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; NRTI, nucleos(t)ide reverse transcriptase inhibitor; PEG-IFNa, pegylated interferon alpha; Q, every; ULN, upper limit of normal; W, weekly.aFibrosis and cirrhosis were defined as FibroScan >8.5 kPa at screening or METAVIR F3 / F4 liver biopsy <1 year.bTobevibart and tobevibart + elebsiran regimens were 44 weeks; tobevibart + elebsiran + PEG-IFNa regimen was 48 weeks.CEOT data available for n = 27 / 50 participants enrolled.dNRTI discontinuation criteria: HBsAg loss, suppressed HBV DNA, HBeAg-negativity, and ALT <2* ULN.

[0010] FIGS. 2A to 2F show end of treatment (EOT) HBsAg loss results for part of the clinical study in Example 1. HBsAg loss was defined as serum HBsAg <0.05 lU / mL (lower of limit of quantification). FIG. 2A shows HBsAg loss overall and by baseline serum HBsAg level. HBsAg loss at EOT was similar for tobevibart + elebsiran with or without PEG-IFNa. HBsAg loss at EOT was highest among participants with 5178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202lower baseline serum HBsAg. EOT, end of treatment; HBsAg, hepatitis B surface antigen; PEG-IFNa, pegylated interferon alpha.aEOT data available for n = 27 / 50 participants enrolled.bHBsAg loss defined as serum HBsAg <0.05 lU / mL (lower of limit of quantification). FIG. 2B shows overall HBsAg loss for tobevibart, tobevibart + elebsiran, and tobevibart + elebsiran + PEG-IFNa regimens. FIG. 2C shows HBsAg loss for participants having baseline serum HbsAg levels < 1000 lU / mL for tobevibart, tobevibart + elebsiran, and tobevibart + elebsiran + PEG-IFNa regimens. FIG. 2D shows HBsAg loss for participants having baseline serum HbsAg levels > 1000 lU / mL for tobevibart, tobevibart + elebsiran, and tobevibart + elebsiran + PEG-IFNa regimens.FIG. 2E shows HBsAg loss for participants having baseline serum HbsAg levels < 3000 lU / mL for tobevibart, tobevibart + elebsiran, and tobevibart + elebsiran + PEG-IFNa regimens. FIG. 2F shows HBsAg loss for participants having baseline serum HbsAg levels > 3000 lU / mL for tobevibart, tobevibart + elebsiran, and tobevibart + elebsiran + PEG-IFNa regimens.

[0011] FIG. 3 shows the percentage of participants having anti-HBs >10 mIU / mL at end of treatment. EOT, end of treatment; HBsAg, hepatitis B surface antigen; HBs, hepatitis B surface antibody; PEG-IFNa, pegylated interferon alpha. Anti-HBs levels were determined via Roche Elecsys Anti-HBs kit on the cobas8000 e801 module; a tobevibart-binding blocker was added to samples prior to analysis, preventing assay interference by tobevibart.CEOT data available for n = 27 / 50 participants enrolled.

[0012] FIG. 4 shows end of treatment anti-HBs antibody kinetics. EOT, end of treatment; HBsAg, hepatitis B surface antigen; HBs, hepatitis B surface antibody; PEG-IFNa, pegylated interferon alpha.aHBsAg loss was defined as serum HBsAg <0.05 lU / mL (lower limit of quantification).bAnti-HBs levels were determined via Roche Elecsys Anti-HBs kit on the cobas8000 e801 module; a tobevibart-binding blocker was added to samples prior to analysis, preventing assay interference by tobevibart.CEOT data available for n = 27 / 50 participants enrolled.

[0013] FIG. 5 shows that HBsAg loss was associated with anti-HBs antibody levels. EOT, end of treatment; HBsAg, hepatitis B surface antigen; HBs, hepatitis B 6178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202surface antibody; PEG-IFNa, pegylated interferon alpha.aHBsAg loss was defined as serum HBsAg <0.05 lU / mL (lower limit of quantification).bHBsAg loss was not achieved in the tobevibart monotherapy cohort.cAnti-HBs levels were determined via Roche Elecsys Anti-HBs kit on the cobas8000 e801 module; a tobevibart-binding blocker was added to samples prior to analysis, preventing assay interference by tobevibart.DETAILED DESCRIPTION

[0014] The instant disclosure provides methods of treating hepatitis B virus (HBV) infection, wherein the methods comprise administering an anti-HBV antibody and an anti-HBV siRNA to a subject, and wherein the subject has a serum HBsAg level prior to treatment of less than 3000 lU / mL. In some embodiments, such combination therapies are used to treat chronic hepatitis B. In some embodiments, the subject has a serum HBsAg level less than 1000 lU / mL (< 1000 lU / mL) prior to treatment, at least 1000 lU / mL but less than 3000 lU / mL (>1000 lU / mL and < 3000 lU / mL) prior to treatment, or less than 3000 lU / mL (< 3000 lU / mL) prior to treatment. The instant disclosure also provides compositions for use in such methods, as well as related uses of the compositions in the manufacture of medicaments for use in treating HBV.I. Glossary

[0015] The following sections provide a detailed description of combination therapies for treating HBV infection. Prior to setting forth this disclosure in more detail, it may be helpful to an understanding thereof to provide definitions of certain terms to be used herein. Additional definitions are set forth throughout this disclosure.

[0016] In the present description, the term "about" means ± 20% of the indicated range, value, or structure, unless otherwise indicated.

[0017] The term "comprise" (and similar terms such as "comprising of' and "comprised of') means the presence of the stated features, integers, steps, or components as referred to in the claims, but that it does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.7178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202The term "consisting essentially of' limits the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristics of the claimed invention.

[0018] It should be understood that the terms "a" and "an" as used herein refer to "one or more" of the enumerated components. The use of the alternative (e.g., "or") should be understood to mean either one, both, or any combination thereof of the alternatives, and may be used synonymously with "and / or". As used herein, the terms "include" and "have" are used synonymously, which terms and variants thereof are intended to be construed as non-limiting or open-ended.

[0019] The word "substantially" does not exclude "completely"; e.g, a composition which is "substantially free" from Y may be completely free from Y.Where necessary, the word "substantially" may be omitted from definitions provided herein.

[0020] The term "disease" as used herein is intended to be generally synonymous, and is used interchangeably with, the terms "disorder" and "condition" (as in "medical condition"), in that all reflect an abnormal condition of the human or animal body or of one of its parts that impairs normal functioning, is typically manifested by distinguishing signs and symptoms, and causes the human or animal to have a reduced duration or quality of life.

[0021] As used herein, the terms "peptide", "polypeptide", and "protein" and variations of these terms refer to a molecule, in particular a peptide, oligopeptide, polypeptide, or protein including fusion protein, respectively, comprising at least two amino acids joined to each other by a normal peptide bond, or by a modified peptide bond, such as for example in the cases of isosteric peptides. For example, a peptide, polypeptide, or protein may be composed of amino acids selected from the 20 amino acids defined by the genetic code, linked to each other by a normal peptide bond ("classical" polypeptide). A peptide, polypeptide, or protein can be composed of L-amino acids and / or D-amino acids. In particular, the terms "peptide", "polypeptide", and "protein" also include "peptidomimetics," which are defined as peptide analogs containing non-peptidic structural elements, which peptides are capable of mimicking 8178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202or antagonizing the biological action(s) of a natural parent peptide. A peptidomimetic lacks classical peptide characteristics such as enzymatically scissile peptide bonds. In particular, a peptide, polypeptide, or protein may comprise amino acids other than the 20 amino acids defined by the genetic code in addition to these amino acids, or it can be composed of amino acids other than the 20 amino acids defined by the genetic code. In particular, a peptide, polypeptide, or protein in the context of the present disclosure can equally be composed of amino acids modified by natural processes, such as post-translational maturation processes or by chemical processes, which are well known to a person skilled in the art. Such modifications are fully detailed in the literature. These modifications can appear anywhere in the polypeptide: in the peptide skeleton, in the amino acid chain, or even at the carboxy- or amino-terminal ends. In particular, a peptide or polypeptide can be branched following an ubiquitination or be cyclic with or without branching. This type of modification can be the result of natural or synthetic post-translational processes that are well known to a person skilled in the art. The terms "peptide", "polypeptide", or "protein" in the context of the present disclosure in particular also include modified peptides, polypeptides, and proteins. For example, peptide, polypeptide, or protein modifications can include acetylation, acylation, ADP-ribosylation, amidation, covalent fixation of a nucleotide or of a nucleotide derivative, covalent fixation of a lipid or of a lipidic derivative, the covalent fixation of a phosphatidylinositol, covalent or non-covalent cross- linking, cyclization, disulfide bond formation, demethylation, glycosylation including pegylation, hydroxylation, iodization, methylation, myristoylation, oxidation, proteolytic processes, phosphorylation, prenylation, racemization, seneloylation, sulfatation, amino acid addition such as arginylation, or ubiquitination. Such modifications are fully detailed in the literature (Proteins Structure and Molecular Properties, 2nd Ed., T. E. Creighton, New York (1993); Post-translational Covalent Modifications of Proteins, B. C. Johnson, Ed., Academic Press, New York (1983); Seifter et al., Analysis for protein modifications and nonprotein cofactors, Meth. Enzymol. 1990, 182:626-46; and Rattan et al., Protein Synthesis: Post-translational Modifications and Aging, Ann NY Acad Sci 1992, 663:48-62). Accordingly, the terms "peptide", "polypeptide", and "protein"9178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202include for example lipopeptides, lipoproteins, glycopeptides, glycoproteins, and the like.

[0022] As used herein a "(poly)peptide" comprises a single chain of amino acid monomers linked by peptide bonds as explained above. A "protein", as used herein, comprises one or more, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 (poly)peptides, z.e., one or more chains of amino acid monomers linked by peptide bonds as explained above. In particular embodiments, a protein according to the present disclosure comprises 1, 2, 3, or 4 polypeptides.

[0023] The term "recombinant", as used herein (e.g., a recombinant antibody, a recombinant protein, a recombinant nucleic acid, etc.), refers to any molecule (antibody, protein, nucleic acid, siRNA, efc.) that is prepared, expressed, created, or isolated by recombinant means, and which is not naturally occurring. As used herein, the terms "nucleic acid", "nucleic acid molecule," and "polynucleotide" are used interchangeably and are intended to include DNA molecules and RNA molecules. A nucleic acid molecule may be single-stranded or double-stranded. In particular embodiments, the nucleic acid molecule is double-stranded RNA.

[0024] As used herein, the term "coding sequence" is intended to refer to a polynucleotide molecule, which encodes the amino acid sequence of a protein product. The boundaries of the coding sequence are generally determined by an open reading frame, which usually begins with an ATG start codon.

[0025] The term "expression" as used herein refers to any step involved in the production of the polypeptide, including transcription, post-transcriptional modification, translation, post-translational modification, secretion, or the like.

[0026] As used herein, "Hepatitis B virus," used interchangeably with the term "HBV" refers to the well-known non-cytopathic, liver-tropic DNA virus belonging to the Hepadnaviridae family. The HBV genome is partially double-stranded, circular DNA with four overlapping reading frames (that may be referred to herein as "genes," "open reading frames," or "transcripts"): C, X, P, and S. The core protein is coded for by gene C (HBcAg). Hepatitis B e antigen (HBeAg) is produced by proteolytic processing of the pre-core (pre-C) protein. The DNA polymerase is encoded by gene P.10178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202Gene S is the gene that codes for the surface antigens (HBsAg). The HBsAg gene is one long open reading frame which contains three in frame "start" (ATG) codons resulting in polypeptides of three different sizes called large (preSl + preS2 + S), medium or middle (preS2 + S), and small S antigens (S). Surface antigens, in addition to decorating the envelope of HBV, are also part of subviral particles, which are produced at large excess as compared to virion particles, and play a role in immune tolerance and in sequestering anti-HBsAg antibodies, thereby allowing for infectious particles to escape immune detection. The protein coded for by gene X plays a role in transcriptional transactivation and replication and is associated with the development of liver cancer.

[0027] As used herein, "serum HBsAg" refers to the amount of surface antigen in the serum of a subject as measured by an immunoassay that detects the presence of conserved amino acids in the small S antigen and therefore includes the levels of all surface antigen proteins ( / .<?., including the large, medium / middle, and small S antigens). Methods for measuring serum HBsAg include, for example, electrochemical immunoassays and chemiluminescent microparticle immunoassays (e.g., Abbott Architect, Roche Cobas).

[0028] Nine genotypes of HBV, designated A to I, have been determined, and an additional genotype J has been proposed, each having a distinct geographical distribution (Velkov S et al., The Global Hepatitis B Virus Genotype Distribution Approximated from Available Genotyping Data, Genes 2018, 9(10):495). The term "HBV" includes any of the genotypes of HBV (A to J). The complete coding sequence of the reference sequence of the HBV genome may be found in for example, GenBank Accession Nos. GF21326584 and GF3582357. Amino acid sequences for the C, X, P, and S proteins can be found at, for example, NCBI Accession numbersYP 009173857.1 (C protein); YP_009173867.1 and BAA32912.1 (X protein);YP 009173866.1 and BAA32913.1 (P protein); and YP 009173869.1,YP 009173870.1, YP_009173871.1, and BAA32914.1 (S protein). Additional examples of HBV messenger RNA (mRNA) sequences are available using publicly available databases, e.g., GenBank, UniProt, and OMIM. The International Repository for Hepatitis B Virus Strain Data can be accessed at http: / / www.hpa- 11178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202bioinformatics.org.uk / HepSEQ / main.php. The term "HBV," as used herein, also refers to naturally occurring DNA sequence variations of the HBV genome, / .<?., genotypes A-J and variants thereof.

[0029] In some embodiments, the present disclosure provides combination therapy to treat HBV that includes an anti-HBV siRNA. siRNA mediates the targeted cleavage of an RNA transcript via an RNA-induced silencing complex (RISC) pathway, thereby effecting inhibition of gene expression. This process is frequently termed "RNA interference" (RNAi). Without wishing to be bound to a particular theory, long doublestranded RNA (dsRNA) introduced into plants and invertebrate cells is broken down into siRNA by a Type III endonuclease known as Dicer (Sharp et al., Genes Dev. 2001, 15:485). Dicer, a ribonuclease-III-like enzyme, processes the dsRNA into 19-23 base pair siRNAs with characteristic two base 3' overhangs (Bernstein et al., Nature 2001, 409:363). The siRNAs are then incorporated into RISC where one or more helicases unwind the siRNA duplex, enabling the complementary antisense strand to guide target recognition (Nykanen et al., Cell 2001, 107:309). Upon binding to the appropriate target mRNA, one or more endonucleases within RISC cleaves the target to induce silencing (Elbashir et al., Genes Dev. 2001, 15:188).

[0030] The terms "silence," "inhibit the expression of," "down-regulate the expression of," "suppress the expression of," and the like, in so far as they refer to an HBV gene, herein refer to the at least partial reduction of the expression of an HBV gene, as manifested by a reduction of the amount of HBV mRNA which can be isolated from or detected in a first cell or group of cells in which an HBV gene is transcribed and which has or have been treated with an inhibitor of HBV gene expression, such that the expression of the HBV gene is inhibited, as compared to a second cell or group of cells substantially identical to the first cell or group of cells but which has or have not been so treated (control cells). The degree of inhibition can be measured, by example, as the difference between the degree of mRNA expression in a control cell minus the degree of mRNA expression in a treated cell. Alternatively, the degree of inhibition can be given in terms of a reduction of a parameter that is functionally linked to HBV gene expression, e.g., the amount of protein encoded by an HBV gene, or the number of cells 12178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202displaying a certain phenotype, e.g., an HBV infection phenotype. In principle, HBV gene silencing can be determined in any cell expressing the HBV gene, e.g., an HBV-infected cell or a cell engineered to express the HBV gene, and by any appropriate assay.

[0031] The level of HBV RNA that is expressed by a cell or group of cells, or the level of circulating HBV RNA, may be determined using any method known in the art for assessing mRNA expression, such as the rtPCR method provided in Example 2 of International Application Publication No. WO2016 / 077321A1 and U.S. Patent Application Publication No. US2017 / 0349900A1, which methods are incorporated herein by reference. In some embodiments, the level of expression of an HBV gene (e.g., total HBV RNA, an HBV transcript, e.g., HBV 3.5 kb transcript) in a sample is determined by detecting a transcribed polynucleotide, or portion thereof, e.g., RNA of the HBV gene. RNA may be extracted from cells using RNA extraction techniques including, for example, using acid phenol / guanidine isothiocyanate extraction (RNAzol B; Biogenesis), RNeasy RNA preparation kits (Qiagen®), or PAXgene (PreAnalytix, Switzerland). Typical assay formats utilizing ribonucleic acid hybridization include nuclear run-on assays, RT-PCR, RNase protection assays (Melton DA et al., Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter, Nuc. Acids Res. 1984, 12:7035-56), northern blotting, in situ hybridization, and microarray analysis. Circulating HBV mRNA may be detected using methods the described in International Application Publication No. WO2012 / 177906A1 and U.S. Patent Application Publication No.US2014 / 0275211 Al, which methods are incorporated herein by reference.

[0032] As used herein, "target sequence" refers to a contiguous portion of the nucleotide sequence of an mRNA molecule formed during the transcription of an HBV gene, including mRNA that is a product of RNA processing of a primary transcription product. The target portion of the sequence will be at least long enough to serve as a substrate for RNAi-directed cleavage at or near that portion. For example, the target sequence will generally be from 9-36 nucleotides in length, e.g., 15-30 nucleotides in length, including all sub-ranges there between. As non-limiting examples, a target 13178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202sequence can be from 15-30 nucleotides, 15-26 nucleotides, 15-23 nucleotides, 15-22 nucleotides, 15-21 nucleotides, 15- 20 nucleotides, 15-19 nucleotides, 15-18 nucleotides, 15-17 nucleotides, 18-30 nucleotides, 18-26 nucleotides, 18-23 nucleotides, 18-22 nucleotides, 18-21 nucleotides, 18-20 nucleotides, 19-30 nucleotides, 19-26 nucleotides, 19-23 nucleotides, 19-22 nucleotides, 19- 21 nucleotides, 19-20 nucleotides, 20-30 nucleotides, 20-26 nucleotides, 20-25 nucleotides, 20- 24 nucleotides, 20-23 nucleotides, 20-22 nucleotides, 20-21 nucleotides, 21-30 nucleotides, 21-26 nucleotides, 21-25 nucleotides, 21-24 nucleotides, 21-23 nucleotides, or 21- 22 nucleotides.

[0033] As used herein, the term "strand comprising a sequence" refers to an oligonucleotide comprising a chain of nucleotides that is described by the sequence referred to using the standard nucleotide nomenclature.

[0034] As used herein, and unless otherwise indicated, the term "complementary," when used to describe a first nucleotide sequence in relation to a second nucleotide sequence, refers to the ability of an oligonucleotide or polynucleotide comprising the first nucleotide sequence to hybridize and form a duplex structure under certain conditions with an oligonucleotide or polynucleotide comprising the second nucleotide sequence, as will be understood by the skilled person. Such conditions can, for example, be stringent conditions, where stringent conditions can include: 400 mM NaCl, 40 mM PIPES pH 6.4, 1 mM EDTA, 50°C or 70°C for 12-16 hours followed by washing. Other conditions, such as physiologically relevant conditions as can be encountered inside an organism, can apply. The skilled person will be able to determine the set of conditions most appropriate for a test of complementarity of two sequences in accordance with the ultimate application of the hybridized nucleotides.

[0035] Complementary sequences within an siRNA as described herein include base-pairing of the oligonucleotide or polynucleotide comprising a first nucleotide sequence to an oligonucleotide or polynucleotide comprising a second nucleotide sequence over the entire length of one or both nucleotide sequences. Such sequences can be referred to as "fully complementary" with respect to each other herein. However, where a first sequence is referred to as "substantially complementary" with respect to a 14178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202second sequence herein, the two sequences can be fully complementary, or they can form one or more, but generally not more than 5, 4, 3, or 2 mismatched base pairs upon hybridization for a duplex up to 30 base pairs, while retaining the ability to hybridize under the conditions most relevant to their ultimate application, e.g., inhibition of gene expression via a RISC pathway. However, where two oligonucleotides are designed to form, upon hybridization, one or more single stranded overhangs, such overhangs shall not be regarded as mismatches with regard to the determination of complementarity. For example, an siRNA comprising one oligonucleotide 21 nucleotides in length, and another oligonucleotide 23 nucleotides in length, wherein the longer oligonucleotide comprises a sequence of 21 nucleotides that is fully complementary to the shorter oligonucleotide, can yet be referred to as "fully complementary" for the purposes described herein.

[0036] "Complementary" sequences, as used herein, can also include, or be formed entirely from non-Watson-Crick base pairs and / or base pairs formed from nonnatural and modified nucleotides, in so far as the above requirements with respect to their ability to hybridize are fulfilled. Such non-Watson-Crick base pairs include, but are not limited to, G:U Wobble or Hoogstein base pairing.

[0037] The terms "complementary," "fully complementary," and "substantially complementary" herein can be used with respect to the base matching between the sense strand and the antisense strand of an siRNA, or between the antisense strand of an siRNA agent and a target sequence, as will be understood from the context of their use.

[0038] As used herein, a polynucleotide that is "substantially complementary" to at least part of a mRNA refers to a polynucleotide that is substantially complementary to a contiguous portion of the mRNA of interest (e.g., an mRNA encoding an HBV protein). For example, a polynucleotide is complementary to at least a part of an HBV mRNA if the sequence is substantially complementary to a noninterrupted portion of the HBV mRNA.

[0039] The term small interfering siRNA, or "siRNA," as used herein, refers to an RNA interference molecule that includes an RNA molecule or complex of molecules having a hybridized duplex region that comprises two anti-parallel and substantially 15178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202complementary nucleic acid strands, which will be referred to as having "sense" and "antisense" orientations with respect to a target RNA. The duplex region can be of any length that permits specific degradation of a desired target RNA through a RISC pathway, but will typically range from 9 to 36 base pairs in length, e.g., 15-30 base pairs in length. Considering a duplex between 9 and 36 base pairs, the duplex can be any length in this range, for example, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34, 35, or 36 and any sub-range there between, including, but not limited to 15-30 base pairs, 15-26 base pairs, 15-23 base pairs, 15-22 base pairs, 15-21 base pairs, 15-20 base pairs, 15-19 base pairs, 15-18 base pairs, 15- 17 base pairs, 18-30 base pairs, 18-26 base pairs, 18-23 base pairs, 18-22 base pairs, 18-21 base pairs, 18-20 base pairs, 19-30 base pairs, 19-26 base pairs, 19-23 base pairs, 19-22 base pairs, 19-21 base pairs, 19-20 base pairs, 20-30 base pairs, 20-26 base pairs, 20-25 base pairs, 20-24 base pairs, 20-23 base pairs, 20-22 base pairs, 20-21 base pairs, 21-30 base pairs, 21-26 base pairs, 21-25 base pairs, 21-24 base pairs, 21-23 base pairs, and 21-22 base pairs. siRNAs generated in the cell by processing with Dicer and similar enzymes are generally in the range of 19-22 base pairs in length.

[0040] One strand of the duplex region of an siRNA comprises a sequence that is substantially complementary to a region of a target RNA. The two strands forming the duplex structure can be from a single RNA molecule having at least one self-complementary region, or can be formed from two or more separate RNA molecules. Where the duplex region is formed from two strands of a single molecule, the molecule can have a duplex region separated by a single stranded chain of nucleotides (herein referred to as a "hairpin loop") between the 3 '-end of one strand and the 5'-end of the respective other strand forming the duplex structure. The hairpin loop can comprise at least one unpaired nucleotide; in some embodiments the hairpin loop can comprise at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 20, at least 23 or more unpaired nucleotides. Where the two substantially complementary strands of an siRNA are comprised by separate RNA molecules, those molecules need not, but can be covalently connected. Where the two strands are16178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202connected covalently by means other than a hairpin loop, the connecting structure is referred to as a "linker."

[0041] An siRNA as described herein can be synthesized by standard methods known in the art, e.g., by use of an automated DNA synthesizer, such as are commercially available from, for example, Biosearch, Applied Biosystems, Inc.

[0042] The term "antisense strand" or "guide strand" refers to the strand of an siRNA that includes a region that is substantially complementary to a target sequence. As used herein, the term "region of complementarity" refers to the region on the antisense strand that is substantially complementary to a sequence, for example a target sequence, as defined herein. Where the region of complementarity is not fully complementary to the target sequence, the mismatches can be in the internal or terminal regions of the molecule. Generally, the most tolerated mismatches are in the terminal regions, e.g., within 5, 4, 3, or 2 nucleotides of the 5' and / or 3' terminus.

[0043] The term "sense strand" or "passenger strand" as used herein, refers to the strand of an siRNA that includes a region that is substantially complementary to a region of the antisense strand as that term is defined herein.

[0044] The term "RNA molecule" or "ribonucleic acid molecule" encompasses not only RNA molecules as expressed or found in nature, but also analogs and derivatives of RNA comprising one or more ribonucleotide / ribonucleoside analogs or derivatives as described herein or as known in the art. Strictly speaking, a "ribonucleoside" includes a nucleoside base and a ribose sugar, and a "ribonucleotide" is a ribonucleoside with one, two or three phosphate moieties. However, the terms "ribonucleoside" and "ribonucleotide" can be considered to be equivalent as used herein. The RNA can be modified in the nucleobase structure or in the ribose-phosphate backbone structure, e.g., as described in greater detail below. However, siRNA molecules comprising ribonucleoside analogs or derivatives retain the ability to form a duplex.

[0045] As used herein, the term "nucleotide overhang" refers to at least one unpaired nucleotide that protrudes from the duplex structure of an siRNA. For example, when a 3'-end of one strand of an siRNA extends beyond the 5'-end of the other strand,17178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202or vice versa, there is a nucleotide overhang. An siRNA can comprise an overhang of at least one nucleotide; alternatively the overhang can comprise at least two nucleotides, at least three nucleotides, at least four nucleotides, at least five nucleotides, or more. A nucleotide overhang can comprise or consist of a nucleotide / nucleoside analog, including a deoxynucleotide / nucleoside. The overhang(s) can be on the sense strand, the antisense strand, or any combination thereof. Furthermore, the nucleotide(s) of an overhang can be present on the 5' end, 3' end, or both ends of either an antisense or sense strand of an siRNA.

[0046] The terms "blunt" or "blunt ended" as used herein in reference to an siRNA mean that there are no unpaired nucleotides or nucleotide analogs at a given terminal end of an siRNA, z.e., no nucleotide overhang. One or both ends of an siRNA can be blunt. Where both ends of an siRNA are blunt, the siRNA is said to be "blunt ended." A "blunt ended" siRNA is an siRNA that is blunt at both ends, z.e., has no nucleotide overhang at either end of the molecule. Often such a molecule will be double-stranded over its entire length.

[0047] The present disclosure provides combination therapies to treat HBV that include an anti-HBV antibody. The anti-HBV antibody targets the conserved antigenic loop of HBsAg and neutralizes infection with hepatitis B virus.

[0048] As used herein, the term "antibody" encompasses various forms of antibodies including, without being limited to, whole antibodies, antibody fragments, antigen binding fragments, human antibodies, chimeric antibodies, humanized antibodies, recombinant antibodies, and genetically engineered antibodies (variant or mutant antibodies) as long as the characteristic properties of the antibody are retained. As used herein, the terms "antigen binding fragment," "fragment," and "antibody fragment" are used interchangeably to refer to any fragment of an antibody of the combination therapy that retains the antigen-binding activity of the antibody. Examples of antibody fragments include, but are not limited to, a single chain antibody, Fab, Fab', F(ab')2, Fv, or scFv. Further, the term "antibody" as used herein includes both antibodies and antigen binding fragments thereof.18178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202

[0049] As used herein, a "neutralizing antibody" is one that can neutralize, i.e., prevent, inhibit, reduce, impede, or interfere with, the ability of a pathogen to initiate and / or perpetuate an infection in a host. The terms "neutralizing antibody" and "an antibody that neutralizes" or "antibodies that neutralize" are used interchangeably herein. These antibodies can be used alone, or in combination, as prophylactic or therapeutic agents upon appropriate formulation, in association with active vaccination, as a diagnostic tool, or as a production tool as described herein.

[0050] Human antibodies are well-known in the state of the art (van Dijk MA and van de Winkel JC, Curr. Opin. Chem. Biol. 2001, 5:368-74). Human antibodies can also be produced in transgenic animals (e.g., mice) that are capable, upon immunization, of producing a full repertoire or a selection of human antibodies in the absence of endogenous immunoglobulin production. Transfer of the human germ-line immunoglobulin gene array in such germ-line mutant mice will result in the production of human antibodies upon antigen challenge (see, e.g, Jakobovits A. et al., Proc. Natl. Acad. Sci. USA 1993, 90:2551-55; Jakobovits A. et al., Nature 1993, 362:255-258; Bruggemann M. et al., Year Immunol. 1993, 7:3340). Human antibodies can also be produced in phage display libraries (Hoogenboom HR and Winter G, Mol. Biol. 1992, 227:381-88; Marks JD et al., Mol Biol. 1991, 222:581-97). The techniques of Cole et al. and Boemer et al. are also available for the preparation of human monoclonal antibodies (Cole et al., Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, p. 77 (1985); Boemer P et al., Immunol. 1991, 147:86-95). In some embodiments, human monoclonal antibodies are prepared by using improved EBV-B cell immortalization as described in Traggiai E et al. (Nat Med. 2004, 10(8): 871 -5). The term "human antibody" as used herein also comprises such antibodies that are modified, e.g, in the variable region, to generate properties as described herein.

[0051] As used herein, the term "variable region" (variable region of a light chain (VL), variable region of a heavy chain (VH)) denotes the portion of an antibody light chain (LC) or heavy chain (HC) (typically around the 105-120 amino-terminal amino acids of a mature antibody heavy chain or light chain) that comprises complementarity determining regions ("CDRs") and framework regions ("FRs"), and 19178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202that is involved directly in binding the antibody to the antigen. The terms "complementarity determining region," and "CDR," are synonymous with "hypervariable region" or "HVR," and are known in the art to refer to non-contiguous sequences of amino acids within antibody variable regions, which confer antigen specificity and / or binding affinity. In general, there are three CDRs in each variable region of an immunoglobulin binding protein; e.g., for antibodies, the VH and VL regions generally comprise six CDRs (CDRH1, CDRH2, CDRH3; CDRL1, CDRL2, CDRL3). Immunoglobulin sequences can be aligned to a numbering scheme (e.g., Kabat, EU, International Immunogenetics Information System (IMGT) and Aho), which can allow equivalent residue positions to be annotated and for different molecules to be compared using Antigen receptor Numbering And Receptor Classification (ANARCI) software tool (Bioinformatics 2016, 15:298-300). It will be understood that in certain instances, an antibody or antigen binding fragment of the present disclosure can comprise all or part of a heavy chain (HC), a light chain (LC), or both. For example, a full-length intact IgG antibody monomer typically includes a VH, a CHI, a CH2, a CH3, a VL, and a CL.

[0052] Antibodies according to the present disclosure may be provided in purified form. Typically, the antibody will be present in a composition that is substantially free of other polypeptides e.g., where less than 90% (by weight), usually less than 60% and more usually less than 50% of the composition is made up of other polypeptides.II. siRNA targeting HBV

[0053] In some embodiments, the present disclosure provides methods of treatment involving administering elebsiran, an siRNA that targets HBV mRNA.a. Elebsiran

[0054] Elebsiran is a synthetic, chemically modified siRNA targeting HBV RNA with a covalently attached triantennary N-acetyl-galactosamine (GalNAc) ligand that allows for specific uptake by hepatocytes. Elebsiran targets mRNA encoded by a region of the HBV genome that is common to all HBV viral transcripts and is20178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202pharmacologically active against HBV genotypes A through J. In preclinical models, elebsiran has been shown to inhibit viral replication, translation, and secretion of HBsAg, and may provide or contribute to a functional cure of chronic HBV infections. An siRNA targeting HBV mRNA can have multiple antiviral effects, including degradation of the pgRNA, thus inhibiting viral replication, and degradation of all viral mRNA transcripts, thereby preventing expression of viral proteins. This may result in the return of a functional immune response directed against HBV, either alone or in combination with other therapies. The ability of elebsiran to reduce HBsAg-containing noninfectious subviral particles also distinguishes it from currently available treatments.

[0055] Elebsiran targets and inhibits expression of an mRNA encoded by an HBV genome according to NCBI Reference Sequence NC 003977.2 (GenBank Accession No. GE21326584) (SEQ ID NO:1). More specifically, elebsiran targets an mRNA encoded by a portion of the HBV genome comprising the sequence GTGTGCACTTCGCTTCAC (SEQ ID NO:2), which corresponds to nucleotides 1579-1597 of SEQ ID NO:1. Because transcription of the HBV genome results in polycistronic, overlapping RNAs, elebsiran significantly inhibits expression of most or all HBV transcripts.

[0056] Exemplary methods for synthesizing elebsiran, and experimental data demonstrating silencing of HBV gene expression, are described in International Application Publication No. W02020 / 036862A1 and U.S. Patent Application Publication No. US20210332365A1, which methods and data are incorporated herein by reference.

[0057] Elebsiran has a sense strand comprising 5'-GUGUGCACUUCGCUUCACA -3' (SEQ ID NO:3) and an antisense strand comprising 5'- UGUGAAGCGAAGUGCACACUU -3' (SEQ ID NO:4), wherein the nucleotides include 2'-fluoro (2'F) and 2'-O-methoxy (2'0Me) ribose sugar modifications, phosphorothioate backbone modifications, and a glycol nucleic acid (GNA) modification, and a triantennary N-acetyl-galactosamine (GalNAc) ligand is conjugated to the 3' end of the sense strand, to facilitate delivery to hepatocytes through the asialoglycoprotein receptor (ASGPR). Including modifications, the sense strand of 21178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202elebsiran comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end, and the antisense strand comprises 5'-usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO: 6), wherein the modifications are abbreviated as shown in Table 1.Table 1. Abbreviations of nucleotide monomers used in modified nucleic acid sequence representation. It will be understood that unless otherwise indicated, these monomers. when present in an oligonucleotide, are mutually linked by 5'-3'-phosphodiester bonds.22178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202"

[0058] The triantennary N-acetyl-galactosamine (GalNAc) ligand (indicated by "L" above) conjugated to the 3' end of the sense strand is:The ligand is conjugated to the 3' end of the sense strand as shown in the following schematic:23178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202wherein X is O.b. Pharmaceutical Compositions and Delivery of siRNA

[0059] In some embodiments, pharmaceutical compositions containing an siRNA, as described herein, and a pharmaceutically acceptable carrier or excipient are provided. The pharmaceutical composition containing the siRNA can be used to treat HB V infection. Such pharmaceutical compositions are typically formulated based on the mode of delivery. For example, compositions may be formulated for systemic administration via parenteral delivery, e.g., by subcutaneous (SC) delivery.

[0060] A "pharmaceutically acceptable carrier" or "excipient" is a pharmaceutically acceptable solvent, suspending agent, or any other pharmacologically inert vehicle for delivering one or more agents, such as nucleic acids, to an animal. The excipient can be liquid or solid and is selected, with the planned manner of administration in mind, so as to provide for the desired bulk, consistency, etc., when combined with the agent (e.g., a nucleic acid) and the other components of a given pharmaceutical composition. Typical pharmaceutically acceptable carriers or excipients include, but are not limited to, binding agents (e.g., pregelatinized maize starch, polyvinylpyrrolidone, hydroxypropyl methylcellulose); fillers (e.g., lactose and other sugars, microcrystalline cellulose, pectin, gelatin, calcium sulfate, ethyl cellulose,24178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202polyacrylates, calcium hydrogen phosphate); lubricants (e.g., magnesium stearate, talc, silica, colloidal silicon dioxide, stearic acid, metallic stearates, hydrogenated vegetable oils, com starch, polyethylene glycols, sodium benzoate, sodium acetate); disintegrants (e.g., starch, sodium starch glycolate); and wetting agents (e.g., sodium lauryl sulphate).

[0061] Pharmaceutically acceptable organic or inorganic excipients suitable for non-parenteral administration that do not deleteriously react with nucleic acids can also be used to formulate siRNA compositions. Suitable pharmaceutically acceptable carriers for formulations used in non-parenteral delivery include, but are not limited to, water, salt solutions, alcohols, polyethylene glycols, gelatin, lactose, amylose, magnesium stearate, talc, silicic acid, viscous paraffin, hydroxymethylcellulose, polyvinylpyrrolidone, and the like.

[0062] Formulations for topical administration of nucleic acids can include sterile and non-sterile aqueous solutions, non-aqueous solutions in common solvents such as alcohols, or solutions of the nucleic acids in liquid or solid oil bases. The solutions can also contain buffers, diluents, and other suitable additives.Pharmaceutically acceptable organic or inorganic excipients suitable for non-parenteral administration that do not deleteriously react with nucleic acids can be used.

[0063] In some embodiments, administration of pharmaceutical compositions and formulations described herein can be topical (e.g., by a transdermal patch), pulmonary (e.g., by inhalation or insufflation of powders or aerosols, including by nebulizer); intratracheal; intranasal; epidermal and transdermal; oral; or parenteral. Parenteral administration includes intravenous, intraarterial, subcutaneous, intraperitoneal, and intramuscular injection or infusion; subdermal administration (e.g., via an implanted device); or intracranial administration (e.g., by intraparenchymal, intrathecal, or intraventricular, administration).

[0064] In some embodiments, the pharmaceutical composition comprises a sterile solution of elebsiran formulated in water for subcutaneous injection. In some embodiments, the pharmaceutical composition comprises a sterile solution of elebsiran formulated in water for subcutaneous injection at a free acid concentration of 200 mg / mL.25178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202

[0065] In some embodiments, the pharmaceutical compositions containing elebsiran are administered in dosages sufficient to inhibit expression of an HBV gene. In some embodiments, a dose of an siRNA is in the range of 0.001 to 200.0 milligrams per kilogram body weight of the recipient per day, or in the range of 1 to 50 milligrams per kilogram body weight per day. For example, an siRNA can be administered at 0.01 mg / kg, 0.05 mg / kg, 0.5 mg / kg, 1 mg / kg, 1.5 mg / kg, 2 mg / kg, 3 mg / kg, 10 mg / kg, 20 mg / kg, 30 mg / kg, 40 mg / kg, or 50 mg / kg per single dose. The pharmaceutical composition can be administered once daily, or it can be administered as two, three, or more sub-doses at appropriate intervals throughout the day or even using continuous infusion or delivery through a controlled release formulation. In that case, the siRNA contained in each sub-dose must be correspondingly smaller in order to achieve the total daily dosage. The dosage unit can also be compounded for delivery over several days, e.g., using a conventional sustained release formulation which provides sustained release of the siRNA over a several day period. Sustained release formulations are well known in the art and are particularly useful for delivery of agents at a particular site, such as could be used with the agents of the technology described herein. In such embodiments, the dosage unit contains a corresponding multiple of the daily dose.

[0066] In some embodiments, a pharmaceutical composition comprising elebsiran contains elebsiran at a dose of 0.8 mg / kg, 1.7 mg / kg, 3.3 mg / kg, 6.7 mg / kg, or 15 mg / kg.

[0067] In some embodiments, a pharmaceutical composition comprising elebsiran contains elebsiran at a dose of 20 mg, 50 mg, 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 350 mg, 400 mg, 450 mg, 500 mg, 550 mg, 600 mg, 650 mg, 700 mg, 750 mg, 800 mg, 850 mg, or 900 mg. In some embodiments, the pharmaceutical composition comprises elebsiran at a dose of from 20 mg to 900 mg. In some embodiments, the pharmaceutical composition comprises elebsiran at a dose of from 100 mg to 300 mg. In some embodiments, the pharmaceutical composition comprises elebsiran at a dose of 200 mg.26178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202III. Anti-HBV Antibody

[0068] The present disclosure also provides, in some embodiments, methods of treatment involving administering tobevibart, an anti-HBV antibody.a. Tobevibart

[0069] Tobevibart is an antibody that binds to the antigenic loop region of HBsAg.

[0070] The envelope of the hepatitis B virus contains three "HBV envelope proteins" (also known as "HBsAg", "hepatitis B surface antigen"): S protein (for "small", also referred to as S-HBsAg), M protein (for "middle" or medium, also referred to as M-HBsAg), and L protein (for "large", also referred to as L-HBsAg). S-HBsAg, M-HBsAg, and L- HBsAg share the same C-terminal extremity (also referred to as "S domain", 226 amino acids), which corresponds to the S protein (S-HBsAg) and which is involved in virus assembly and infectivity. S-HBsAg, M-HBsAg, and L-HBsAg are synthesized in the endoplasmic reticulum (ER), assembled, and secreted as particles through the Golgi apparatus. The S domain comprises four predicted transmembrane (TM) domains, whereby both the N-terminus and the C-terminus of the S domain are exposed to the lumen. The transmembrane domains TM1 and TM2 are both necessary for cotranslational protein integration into the ER membrane and the transmembrane domains TM3 and TM4 are located in the C-terminal third of the S domain. The "antigenic loop region" of HBsAg is located between the predicted TM3 and TM4 transmembrane domains of the S domain of HBsAg, whereby the antigenic loop region comprises amino acids 101 - 172 of the S domain (Salisse J and Sureau C, Journal of Virology 2009, 83:9321-8). An important determinant of infectivity resides in the antigenic loop region of HBV envelope proteins. In particular, residues between 119 and 125 of the HBsAg contain a CXXC motif, which has been demonstrated to be the most important sequence required for the infectivity of HBV (Jaoude GA and Sureau C, Journal of Virology 2005, 79:10460-6).

[0071] As used herein, the S domain of HBsAg refers to an amino acid sequence as set forth in SEQ ID NO: 7 (shown below) or to natural or artificial sequence variants thereof.27178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202MENITSGFLGPLLVLQAGFFLLTRILTIPQSLDSWWTSLNFLGGTT VCLGQNSQSPTSNHSPTSCPPTCPGYRWMCLRRFIIFLFILLLCLIF LLVLLDYQGMLPVCPLIPGSSTTSTGPCRTCMTTAQGTSMYPSCC CTKPSDGNCTCIPIPSSWAFGKFLWEWASARFSWLSLLVPFVOWF VGLSPTVWLSVIWMMWYWGPSLYSILSPFLPLLPIFFCLWVYI(SEQ ID NO: 7; amino acids 101 - 172 are shown underlined)

[0072] For example, the expression "amino acids 101 - 172 of the S domain" refers to the amino acid residues from positions 101 - 172 of the polypeptide according to SEQ ID NO:7. However, a person skilled in the art will understand that mutations or variations (including, but not limited to, substitution, deletion and / or addition, for example, HBsAg of a different genotype or a different HBsAg mutant as described herein) may occur naturally in the amino acid sequence of the S domain of HBsAg or be introduced artificially into the amino acid sequence of the S domain of HBsAg without affecting its biological properties. Therefore, the term "S domain of HBsAg" comprises all such polypeptides, for example, including the polypeptide according to SEQ ID NO:7 and its natural or artificial mutants. In addition, when sequence fragments of the S domain of HBsAg are described herein (e.g., amino acids 101 - 172 or amino acids 120 -130 of the S domain of HBsAg), they include not only the corresponding sequence fragments of SEQ ID NO:7, but also the corresponding sequence fragments of its natural or artificial mutants. For example, the expression "amino acid residues from positions 101 - 172 of the S domain of HBsAg" includes amino acid residues from positions 101 - 172 of SEQ ID NO: 7 and the corresponding fragments of its mutants (natural or artificial mutants).

[0073] As used herein, the expression "corresponding sequence fragments" or "corresponding fragments" refers to fragments that are located in equal positions of sequences when the sequences are subjected to optimized alignment, namely, the sequences are aligned to obtain a highest percentage of identity. The M protein (M-HBsAg) corresponds to the S protein extended by an N-terminal domain of 55 amino acids called "preS2". The L protein (L-HBsAg) corresponds to the M protein extended by an N-terminal domain of 108 amino acids called "preSl" (genotype D). The preSl 28178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202and preS2 domains of the L protein can be present either at the inner face of viral particles (on the cytoplasmic side of the ER), playing a crucial role in virus assembly, or on the outer face (on the luminal side of the ER), available for the interaction with target cells and necessary for viral infectivity. Moreover, HBV surface proteins (HBsAgs) are not only incorporated into virion envelopes but also spontaneously bud from ER-Golgi intermediate compartment membranes to form empty "subviral particles" (SVPs) that are released from the cell by secretion.

[0074] Since all three HBV envelope proteins S-HBsAg, M-HBsAg, and L-HBsAg comprise the S domain, all three HBV envelope proteins S-HBsAg, M-HBsAg, and L-HBsAg also comprise the "antigenic loop region". Accordingly, an antibody or an antigen binding fragment thereof that binds to the antigenic loop region of HBsAg binds to all three HBV envelope proteins: S-HBsAg, M-HBsAg, and L-HBsAg.

[0075] The anti-HB V antibody of the combination therapy neutralizes infection with hepatitis B virus. To study and quantitate virus infectivity (or "neutralization") in the laboratory the person skilled in the art knows various standard "neutralization assays." For a neutralization assay, animal viruses are typically propagated in cells and / or cell lines. In the context of the present disclosure, for a neutralization assay, cultured cells may be incubated with a fixed amount of HBV in the presence (or absence) of the antibody to be tested. As a readout, the levels of hepatitis B surface antigen (HBsAg) or hepatitis B e antigen (HBeAg) secreted into the cell culture supernatant may be used and / or HBeAg staining may be assessed. In one embodiment of a HBV neutralization assay, cultured cells, for example HepaRG cells, in particular differentiated HepaRG cells, are incubated with a fixed amount of HBV in the presence or absence of the antibody to be tested, for example for 16 hours at 37°C. The incubation may be performed in a medium (e.g., supplemented with 4% PEG 8000). After incubation, cells may be washed and further cultivated. To measure virus infectivity, the levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) secreted into the culture supernatant, e.g., from day 7 to day 11 post-infection, may be determined by enzyme-linked immunosorbent assay (ELISA). Additionally, HBeAg staining may be assessed in an immunofluorescence assay.29178456543.1179216384.1Vir Ref P0237.WO1PCT Fox Ref 368561.45202

[0076] Table 2 shows the amino acid sequences of the CDRs, heavy chain variable region (VH), light chain variable region (VL), full-length heavy chain (HC), and full-length light chain (LC) of tobevibart.Table 2, Amino acid sequences for tobevibart.<<<30178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202<<<31178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202

[0077] Exemplary methods for synthesizing antibodies having sequences shown in Table 2, and experimental data demonstrating binding and neutralization by tobevibart, are described in International Application Publication No.W02020 / 132091 A2 and U.S. Patent Application Publication No. US20220127336A1, which methods and data are incorporated herein by reference.

[0078] An antibody of the present disclosure may comprise: (i) CDRH1, CDRH2, and CDRH3 amino acid sequences according to SEQ ID NOs:8, 9 or 10, and 11, respectively; and (ii) CDRL1, CDRL2, and CDRL3 amino acid sequences according to SEQ ID NOs:12, 13 or 14, and 15, respectively.

[0079] An antibody of the present disclosure may comprise: (i) the VH amino acid sequence according to SEQ ID NOs: 16; and (ii) the VL amino acid sequence according to SEQ ID NO: 17.

[0080] In some embodiments, a binding protein (e.g., antibody or an antigen binding fragment thereof) comprises an Fc moiety. As used herein, the term "Fc moiety" refers to a sequence comprising or derived from a portion of an immunoglobulin heavy chain beginning in the hinge region just upstream of the papain cleavage site (e.g., residue 216 in native IgG, taking the first residue of heavy chain constant region to be 114) and ending at the C-terminus of the immunoglobulin heavy chain.

[0081] Tobevibart comprises a Fc moiety containing amino acid modifications that improve binding affinity for FcRn and, in some embodiments, thereby extend in vivo half-life of a molecule comprising the Fc moiety (e.g., as compared to a reference Fc moiety or antibody that does not comprise the modification(s)). For example, tobevibart comprises the half-life-extending M428L / N434S mutations that increase binding affinity of an Fc moiety to an FcRn receptor.

[0082] Tobevibart comprises a Fc moiety containing amino acid modifications that improve binding affinity to certain Fey receptors. For example, tobevibart comprises G236A / A330L / I332E mutations that increase binding affinity of an Fc moiety to Fey receptors FcyllA and FcylllA.b. Pharmaceutical Compositions and Delivery of Antibody32178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202

[0083] In some embodiments, an antibody of the combination therapy is provided as a pharmaceutical composition, which includes the anti-HBV antibody and optionally, a pharmaceutically acceptable carrier. In some embodiments, a composition may include an anti-HBV antibody, wherein the antibody may make up at least 50% by weight (e.g., 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or more) of the total protein in the composition. In such a composition, the antibody may be in purified form.

[0084] Pharmaceutical compositions of the anti-HBV antibody may include an antimicrobial, particularly if packaged in a multiple dose format. They may comprise detergent, e.g., a Tween (polysorbate), such as Tween 80. When present, detergents are typically present at low levels, e.g., less than 0.01%. Compositions may also include sodium salts (e.g., sodium chloride) for tonicity. For example, in some embodiments, a pharmaceutical composition comprises NaCl at a concentration of 10±2mg / ml.

[0085] Further, pharmaceutical compositions may comprise a sugar alcohol (e.g., mannitol) or a disaccharide (e.g., sucrose or trehalose), e.g., at around 15-30 mg / ml (e.g., 25 mg / ml), particularly if they are to be lyophilized or if they include material which has been reconstituted from lyophilized material. The pH of a composition for lyophilization may be adjusted to between 5 and 8, or between 5.5 and 7, or around 6.1 prior to lyophilization.

[0086] An antibody composition of the present disclosure may also comprise one or more immunoregulatory agents. In some embodiments, one or more of the immunoregulatory agents include(s) an adjuvant.

[0087] Methods of preparing a pharmaceutical composition of the anti-HBV antibody may include the steps: (i) preparing the antibody; and (ii) admixing the purified antibody with one or more pharmaceutically acceptable carriers.

[0088] In some embodiments, a pharmaceutical composition comprising tobevibart described herein contains tobevibart at a dose of 100 mg, 150 mg, 200 mg, 250 mg, or 300 mg. In some embodiments, a pharmaceutical composition comprising tobevibart contains tobevibart at a dose of from 100 mg to 300 mg. In some embodiments, a pharmaceutical composition comprising tobevibart contains tobevibart 33178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202at a dose of from 200 mg to 400 mg. In some embodiments, a pharmaceutical composition comprising tobevibart contains tobevibart at a dose of 300 mg.IV. Methods of Treatment using Combination Therapies

[0089] In some embodiments, the present disclosure provides methods for treating HBV infection in a subject, wherein the subject has a serum HBsAg level less than 3000 lU / mL (<3000 lU / mL) prior to treatment and / or at baseline. In some embodiments, the subject has a serum HBsAg level less than 1000 lU / mL (< 1000 lU / mL) prior to treatment and / or at baseline. In some embodiments, the subject has a serum HBsAg level of 1000 lU / mL or more but less than 3000 lU / mL (>1000 lU / mL and < 3000 lU / mL) prior to treatment and / or at baseline.

[0090] In some embodiments, the present disclosure provides methods for reducing the serum HBsAg level in a subject, wherein the subject has a serum HBsAg level less than 3000 lU / mL (<3000 lU / mL) prior to treatment and / or at baseline. In some embodiments, the subject has a serum HBsAg level less than 1000 lU / mL (< 1000 lU / mL) prior to treatment and / or at baseline. In some embodiments, the subject has a serum HBsAg level of 1000 lU / mL or more but less than 3000 lU / mL (>1000 lU / mL and < 3000 lU / mL) prior to treatment and / or at baseline.

[0091] In some embodiments, the present disclosure provides methods for reducing or inhibiting HBV replication in a subject, wherein the subject has a serum HBsAg level less than 3000 lU / mL (<3000 lU / mL) prior to treatment and / or at baseline. In some embodiments, the subject has a serum HBsAg level less than 1000 lU / mL (< 1000 lU / mL) prior to treatment and / or at baseline. In some embodiments, the subject has a serum HBsAg level of 1000 lU / mL or more but less than 3000 lU / mL (>1000 lU / mL and < 3000 lU / mL) prior to treatment and / or at baseline.

[0092] As used herein, a "subject" is human that has a hepatitis B virus (HBV) infection.

[0093] As used herein, the terms "treating" or "treatment" refer to a beneficial or desired result including, but not limited to, alleviation or amelioration of one or more signs or symptoms associated with unwanted HBV gene expression or HBV replication,34178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202e.g., the presence of serum or liver HBV cccDNA, the presence of serum HBV DNA, the presence of serum or liver HBV antigen, e.g., HBsAg or HBeAg, elevated ALT, elevated AST (normal range is typically considered about 10 to 34 U / L), the absence of or low level of anti-HBV antibodies; a liver injury; cirrhosis; delta hepatitis; acute hepatitis B; acute fulminant hepatitis B; chronic hepatitis B; liver fibrosis; end-stage liver disease; hepatocellular carcinoma; serum sickness-like syndrome; anorexia; nausea; vomiting, low-grade fever; myalgia; fatigability; disordered gustatory acuity and smell sensations (aversion to food and cigarettes); or right upper quadrant and epigastric pain (intermittent, mild to moderate); hepatic encephalopathy; somnolence; disturbances in sleep pattern; mental confusion; coma; ascites; gastrointestinal bleeding; coagulopathy; jaundice; hepatomegaly (mildly enlarged, soft liver); splenomegaly; palmar erythema; spider nevi; muscle wasting; spider angiomas; vasculitis; variceal bleeding; peripheral edema; gynecomastia; testicular atrophy; abdominal collateral veins (caput medusa); ALT levels higher than AST levels; elevated gamma-glutamyl transpeptidase (GGT) (normal range is typically considered about 8 to 65 U / L) and alkaline phosphatase (ALP) levels (normal range is typically considered about 44 to 147 IU / L (international units per liter), not more than 3 times the ULN); slightly low albumin levels; elevated serum iron levels; leukopenia (i.e., granulocytopenia); lymphocytosis; increased erythrocyte sedimentation rate (ESR); shortened red blood cell survival; hemolysis; thrombocytopenia; a prolongation of the international normalized ratio (INR); presence of serum or liver HBsAg, HBeAg, Hepatitis B core antibody (anti-HBc) immunoglobulin M (IgM); hepatitis B surface antibody (anti-HBs), hepatitis B e antibody (anti-HBe), or HBV DNA; increased bilirubin levels; hyperglobulinemia; the presence of tissue-nonspecific antibodies, such as anti-smooth muscle antibodies (ASMAs) or antinuclear antibodies (ANAs) (10-20%); the presence of tissue-specific antibodies, such as antibodies against the thyroid gland (10-20%); elevated levels of rheumatoid factor (RF); low platelet and white blood cell counts; lobular, with degenerative and regenerative hepatocellular changes, and accompanying inflammation; and predominantly centrilobular necrosis, whether detectable or undetectable. The likelihood of developing, e.g., liver fibrosis, is reduced, for example,35178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202when an individual having one or more risk factors for liver fibrosis, e.g., chronic hepatitis B infection, either fails to develop liver fibrosis or develops liver fibrosis with less severity relative to a population having the same risk factors and not receiving treatment as described herein. "Treatment" can also mean prolonging survival as compared to expected survival in the absence of treatment.

[0094] As used herein, the terms "preventing" or "prevention" refer to the failure to develop a disease, disorder, or condition, or the reduction in the development of a sign or symptom associated with such a disease, disorder, or condition (e.g., by a clinically relevant amount), or the exhibition of delayed signs or symptoms delayed (e.g., by days, weeks, months, or years). Prevention may require the administration of more than one dose.

[0095] Doses are often expressed in relation to bodyweight. Thus, a dose which is expressed as [g, mg, or other unit] / kg (or g, mg, etc.} usually refers to [g, mg, or other unit] "per kg (or g, mg, etc. bodyweight," even if the term "bodyweight" is not explicitly mentioned.

[0096] "Therapeutically effective amount," as used herein, is intended to include the amount of an siRNA, an anti-HBV antibody, or other active agent (e.g., PEG-IFNa, tenofovir), that, when administered to a patient for treating a subject having an HBV infection or HBV-associated disease, is sufficient to effect treatment of the disease (e.g., by diminishing or maintaining the existing disease or one or more symptoms of disease). The "therapeutically effective amount" may vary depending on the active agent(s), how they are administered, the disease and its severity, and the history, age, weight, family history, genetic makeup, stage of pathological processes mediated by HBV gene expression, the types of preceding or concomitant treatments, if any, and other individual characteristics of the patient to be treated. A therapeutically effective amount may require the administration of more than one dose.

[0097] A "therapeutically effective amount" also includes an amount of an siRNA, an anti-HBV antibody, or other active agent that produces some desired effect at a reasonable benefit / risk ratio applicable to any treatment. Therapeutic agents (e.g. , siRNAs, anti-HBV antibodies) used in the methods of the present disclosure may be 36178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202administered in a sufficient amount to produce a reasonable benefit / risk ratio applicable to such treatment.

[0098] The term "sample," as used herein, includes a collection of similar fluids, cells, or tissues isolated from a subject, as well as fluids, cells, or tissues present within a subject. Examples of biological fluids include blood, serum, and serosal fluids, plasma, lymph, urine, saliva, and the like. Tissue samples may include samples from tissues, organs or localized regions. For example, samples may be derived from particular organs, parts of organs, or fluids or cells within those organs. In certain embodiments, samples may be derived from the liver (e.g., whole liver or certain segments of liver or certain types of cells in the liver, such as, e.g., hepatocytes). In certain embodiments, a "sample derived from a subject" refers to blood, or plasma or serum obtained from blood drawn from the subject. In further embodiments, a "sample derived from a subject" refers to liver tissue (or subcomponents thereof) or blood tissue (or subcomponents thereof, e.g, serum) derived from the subject.

[0099] Tobevibart promotes clearance of HBsAg and HBV. In particular, tobevibart may promote clearance of both HBV and subviral particles of hepatitis B virus (SVPs). Clearance of HBsAg or of subviral particles may be assessed by measuring the level of HBsAg for example in a blood sample, e.g, from a hepatitis B patient. Similarly, clearance of HBV may be assessed by measuring the level of HBV for example in a blood sample, e.g., from a hepatitis B patient.

[0100] In the sera of patients infected with HBV, in addition to infectious particles (HBV), there is typically an excess (typically 1,000- to 100,000-fold) of empty subviral particles (SVP) composed solely of HBV envelope proteins (HBsAg) in the form of relatively smaller spheres and filaments of variable length. Subviral particles were shown to strongly enhance intracellular viral replication and gene expression of HBV (Bruns M et al., J Virol 1998, 72(2): 1462-8). This is also important in the context of infectivity of sera containing HBV, since the infectivity depends not only on the number of viruses but also on the number of SVPs (Bruns et al., 1998, supra).Moreover, an excess of subviral particles can serve as a decoy by absorbing neutralizing antibodies and therefore delay the clearance of infection. Typically, achievement of 37178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202hepatitis B surface antigen (HBsAg) loss is thus considered to be an ideal endpoint of treatment and the closest outcome to cure chronic hepatitis B (CHB). Accordingly, in some embodiments, tobevibart promotes clearance of HBsAg, and in particular, clearance of subviral particles of hepatitis B virus and HBV, enables improved treatment of hepatitis B, in particular in the context of chronic hepatitis B. Thereby, tobevibart may potently neutralize HBV since less of the antibody is absorbed by SVPs acting as a decoy. In addition, in certain embodiments, tobevibart promotes clearance of subviral particles of hepatitis B virus, and decreases infectivity of HBV in sera.

[0101] In some embodiments, methods for treating HBV infection in a subject further comprise administering an interferon a (e.g., PEG-IFNa, pegylated interferon alfa-2a) to the subject.

[0102] In some embodiments, methods for treating HBV infection in a subject further comprise administering a nucleoside / nucleotide reverse transcriptase inhibitor to the subject. As used herein, "nucleoside / nucleotide reverse transcriptase inhibitor" or "nucleos(t)ide reverse transcriptase inhibitor" (NRTI) refers to an inhibitor of DNA replication that is structurally similar to a nucleotide or nucleoside and specifically inhibits replication of the HBV cccDNA by inhibiting the action of HBV polymerase, and does not significantly inhibit the replication of the host (e.g., human) DNA. Such inhibitors include tenofovir, tenofovir disoproxil fumarate (TDF), tenofovir disoproxil (TD), tenofovir alafenamide (TAF), lamivudine, adefovir, adefovir dipivoxil, entecavir (ETV), telbivudine, AGX-1009, emtricitabine (FTC), clevudine, ritonavir, dipivoxil, lobucavir, famvir, N-Acetyl-Cysteine (NAC), PC1323, theradigm-HBV, thymosinalpha, ganciclovir, besifovir (ANA-380 / LB-80380), and tenofvir-exaliades (TLX / CMX157). In some embodiments, the NRTI is tenofovir. In some embodiments, the NRTI is tenofovir disoproxil fumarate (TDF). In some embodiments, the NRTI is disoproxil (TD). In some embodiments, the NRTI is entecavir (ETV). In some embodiments, the NRTI is lamivudine. In some embodiments, the NRTI is adefovir or adefovir dipivoxil.

[0103] In some embodiments, treatment of HBV infection results in a "functional cure" of hepatitis B. As used herein, functional cure is understood as 38178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202clearance of circulating HBsAg and may be accompanied by conversion to a status in which HBsAg antibodies become detectable using a clinically relevant assay. For example, detectable antibodies can include a signal higher than 10 mIU / ml as measured by Chemiluminescent Microparticle Immunoassay (CMIA) or any other immunoassay. Functional cure does not require clearance of all replicative forms of HBV (e.g., cccDNA from the liver). Anti-HBs seroconversion occurs spontaneously in about 0.2-1% of chronically infected patients per year. However, even after anti-HBs seroconversion, low level persistence of HBV is often observed for decades indicating that a functional rather than a complete cure occurs. Without being bound to a particular mechanism, the immune system may be able to keep HBV in check under conditions in which a functional cure has been achieved. A functional cure permits discontinuation of any treatment for the HBV infection. However, it is understood that a "functional cure" for HBV infection may not be sufficient to prevent or treat diseases or conditions that result from HBV infection, e.g., liver fibrosis, HCC, or cirrhosis. In some specific embodiments, a "functional cure" can refer to a sustained reduction in serum HBsAg, such as <1 lU / mL, for at least 3 months, at least 6 months, or at least one year following the initiation of a treatment regimen or the completion of a treatment regimen.

[0104] In some embodiments, is the subject has chronic hepatitis B. Chronic hepatitis B is defined by one of the following criteria: (1) positive serum HBsAg, HBV DNA, or HBeAg on two occasions at least 6 months apart (any combination of these tests performed 6 months apart is acceptable); or (2) negative immunoglobulin M (IgM) antibodies to HBV core antigen (IgM anti-HBc) and a positive result on one of the following tests: HBsAg, HBeAg, or HBV DNA. Chronic HBV typically includes inflammation of the liver that lasts more than six months. Subjects having chronic HBV are HBsAg positive and have either high viremia (>104HBV-DNA copies / ml blood) or low viremia (<103HBV-DNA copies / ml blood). In certain embodiments, subjects have been infected with HBV for at least five years. In certain embodiments, subjects have been infected with HBV for at least ten years. In certain embodiments, subjects became infected with HBV at birth. Subjects having chronic hepatitis B disease can be immune tolerant or have an inactive chronic infection without any evidence of active 39178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202disease, and they are also asymptomatic. Patients with chronic active hepatitis, especially during the replicative state, may have symptoms similar to those of acute hepatitis. Subjects having chronic hepatitis B disease may have an active chronic infection accompanied by necroinflammatory liver disease, have increased hepatocyte turn-over in the absence of detectable necroinflammation, or have an inactive chronic infection without any evidence of active disease, and they are also asymptomatic. The persistence of HBV infection in chronic HBV subjects is the result of cccHBV DNA. In some embodiments, a subject having chronic HBV is HBeAg positive. In some other embodiments, a subject having chronic HBV is HBeAg negative. Subjects having chronic HBV have a level of serum HBV DNA of less than 105 and a persistent elevation in transaminases, for examples ALT, AST, and gamma-glutamyl transferase. A subject having chronic HBV may have a liver biopsy score of less than 4 (e.g., a necroinflammatory score).

[0105] In some embodiments, is the subject has a hepatitis D virus infection. Hepatitis D virus or hepatitis delta virus (HDV) is a human pathogen. However, the virus is defective and depends on obligatory helper functions provided by HBV for transmission; indeed, HDV requires an associated or pre-existing HBV infection to become infectious and thrive, in particular, the viral envelope containing the surface antigen of hepatitis B. HDV can lead to severe acute and chronic forms of liver disease in association with HBV. Hepatitis D infection or delta hepatitis is highly endemic to several African countries, the Amazonian region, and the Middle East, while its prevalence is low in industrialized countries, except in the Mediterranean.

[0106] Transmission of HDV can occur either via simultaneous infection with HBV (coinfection) or superimposed on chronic hepatitis B or hepatitis B carrier state (superinfection). Both superinfection and coinfection with HDV typically result in more severe complications compared to infection with HBV alone. These complications include a greater likelihood of experiencing liver failure in acute infections and a rapid progression to liver cirrhosis, with an increased chance of developing liver cancer in chronic infections. In combination with hepatitis B virus, hepatitis D has the highest fatality rate of all the hepatitis infections, at 20%.40178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202

[0107] In some embodiments, the subject has an acute hepatitis B. Acute hepatitis B includes inflammation of the liver that lasts less than six months. Typical symptoms of acute hepatitis B are fatigue, anorexia, nausea, and vomiting. Very high aminotransferase values (>1000 U / L) and hyperbilirubinemia are often observed.Severe cases of acute hepatitis B may progress rapidly to acute liver failure, marked by poor hepatic synthetic function. This is often defined as a prothrombin time (PT) of 16 seconds or an international normalized ratio (INR) of 1.5 in the absence of previous liver disease. Acute hepatitis B may evolve into chronic hepatitis B.

[0108] In some embodiments, the subject has fulminant hepatitis B. A subject having acute fulminant hepatitis B has symptoms of acute hepatitis and the additional symptoms of confusion or coma (due to the liver's failure to detoxify chemicals) and bruising or bleeding (due to a lack of blood clotting factors).

[0109] Subjects having an HBV infection, e.g., chronic HBV, may develop liver fibrosis. Accordingly, in some embodiments, is the subject has liver fibrosis. Liver fibrosis, or cirrhosis, is defined histologically as a diffuse hepatic process characterized by fibrosis (excess fibrous connective tissue) and the conversion of normal liver architecture into structurally abnormal nodules.

[0110] Subjects having an HBV infection, e.g., chronic HBV, may develop endstage liver disease. Accordingly, in some embodiments, is the subject has end-stage liver disease. For example, liver fibrosis may progress to a point where the body may no longer be able to compensate for, e.g., reduced liver function, as a result of liver fibrosis (i.e., decompensated liver), and result in, e.g., mental and neurological symptoms and liver failure.

[0111] Subjects having an HBV infection, e.g., chronic HBV, may develop hepatocellular carcinoma (HCC), also referred to as malignant hepatoma. Accordingly, in some embodiments, is the subject has HCC. HCC commonly develops in subjects having CHB and may be fibrolamellar, pseudoglandular (adenoid), pleomorphic (giant cell), or clear cell.

[0112] In some embodiments of the methods described herein, tobevibart is administered subcutaneously. In some embodiments, tobevibart is administered every 441178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202weeks. In some embodiments, tobevibart is administered every 8-12 weeks, every 8 weeks, or every 12 weeks. In some embodiments, the subject is administered tobevibart for a period of 44 weeks. In some embodiments, the subject is administered tobevibart for a period of 48 weeks. In some embodiments, the subject is administered tobevibart for a period of at least 44 weeks, 44 weeks, 44 weeks or longer, at least 48 weeks, 48 weeks, or 48 weeks or longer. In some embodiments, the subject is administered tobevibart for a period of 20 weeks, 40 weeks, 44 weeks, or 48 weeks. In some embodiments, tobevibart is administered at a dose of from 100 mg to 400 mg. In some embodiments, tobevibart is administered at a dose of 100 mg. In some embodiments, tobevibart is administered at a dose of 150 mg. In some embodiments, tobevibart is administered at a dose of 200 mg. In some embodiments, tobevibart is administered at a dose of 250 mg. In some embodiments, tobevibart is administered at a dose of 300 mg.

[0113] In some embodiments of the methods described herein, elebsiran is administered subcutaneously. In some embodiments, elebsiran is administered every 4 weeks. In some embodiments, the subject is administered elebsiran for a period of 20 weeks, 44 weeks, or 48 weeks. In some embodiments, the subject is administered elebsiran for a period of 44 weeks. In some embodiments, the subject is administered elebsiran for a period of 48 weeks. In some embodiments, the subject is administered elebsiran for a period of at least 44 weeks, 44 weeks, 44 weeks or longer, at least 48 weeks, 48 weeks, or 48 weeks or longer. In some embodiments, elebsiran is administered at a dose of from 20 mg to 900 mg. In some embodiments, elebsiran is administered at a dose of from 100 mg to 300 mg. In some embodiments, elebsiran is administered at a dose of 20 mg, 50 mg, 100 mg, 150 mg, 200 mg, 250 mg, 300 mg, 400 mg, or 450 mg. In some embodiments, elebsiran is administered at a dose of 200 mg.

[0114] In some embodiments of the methods described herein, the interferon-a is administered subcutaneously. In some embodiments, the interferon-a is administered once per week. In some embodiments, the subject is administered the interferon-a for a period of 44 weeks. In some embodiments, the subject is administered the interferon-a for a period of 48 weeks. In some embodiments, the subject is administered the42178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202interferon-a for a period of at least 44 weeks, 44 weeks, 44 weeks or longer, at least 48 weeks, 48 weeks, or 48 weeks or longer. In some embodiments, the interferon-a is administered at a dose of at least 120 mcg. In some embodiments, the interferon-a is administered at a dose of from 120 mcg to 180 mcg. In some embodiments, the interferon-a is administered at a dose of 180 mcg.

[0115] In some embodiments of the methods described herein, the NRTI is administered orally. In some embodiments, the NRTI is administered daily. In some embodiments, the subject is administered the NRTI for a period of 44 weeks. In some embodiments, the subject is administered the NRTI for a period of 48 weeks. In some embodiments, the subject is administered the NRTI for a period of at least 44 weeks, 44 weeks, 44 weeks or longer, at least 48 weeks, 48 weeks, or 48 weeks or longer. In some embodiments, the NRTI is administered at a dose of 300 mg. In some embodiments, the NRTI is administered at a dose of 245 mg.

[0116] In some embodiments of the methods described herein, the subject is administered elebsiran and tobevibart beginning on the same day.

[0117] In some embodiments of the methods described herein, the subject is administered elebsiran and tobevibart beginning on the same day and for a period of 20 weeks, 44 weeks, or 48 weeks.

[0118] In some embodiments of the methods described herein, the subject is HBsAg-negative after treatment, e.g., at 24 weeks, at 48 weeks, or later. In some embodiments of the methods described herein, the subject achieves a functional cure, z.e., has undetectable HBsAg (is HBsAg-negative) and sustained suppression of HBV DNA (HBV DNA not detected) after treatment, e.g., at 24 weeks, at 48 weeks, or later. In some embodiments of the methods described herein, the subject has undetectable HBeAg and / or achieves anti-HBe seroconversion after treatment, e.g., at 24 weeks, at 48 weeks, or later. In some embodiments of the methods described herein, the subject has normal alanine aminotransferase (ALT) levels after treatment, e.g., at 24 weeks, at 48 weeks, or later.

[0119] In some embodiments, methods for treating HBV infection in a subject are provided, wherein the method comprises administering 200 mg of elebsiran and 30043178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202mg of tobevibart to the subject, wherein the subject has a serum HBsAg level < 1000 lU / mL prior to treatment. In some embodiments, methods for treating HB V infection in a subject are provided, wherein the method comprises administering 200 mg of elebsiran and 300 mg of tobevibart to the subject, wherein the subject has a serum HBsAg level >1000 lU / mL and < 3000 lU / mL prior to treatment. In some embodiments, methods for treating HBV infection in a subject are provided, wherein the method comprises administering 200 mg of elebsiran and 300 mg of tobevibart to the subject, wherein the subject has a serum HBsAg level < 3000 lU / mL prior to treatment. In some embodiments, the method further comprises administering 180 mcg of a pegylated interferon-alpha-2a (PEG-IFN-a-2a).

[0120] The present disclosure also provides antibodies, siRNAs, NRTIs, and / or interferons described herein, and pharmaceutical compositions comprising the same, for use in the aforementioned methods. Uses of the antibodies, siRNAs, NRTIs, and / or interferons described herein in the manufacture of a medicament or separate medicaments for use in the aforementioned methods are also provided.V. Example Embodiments

[0121] The following exemplary embodiments are also provided by the present disclosure:1. An antibody for use in a method of treating hepatitis B virus (HBV) infection in a subject having a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the method comprising administering to the subject:(a) an antibody comprising a light chain amino acid sequence according to SEQ ID NO: 19 and a heavy chain amino acid sequence according to SEQ ID NO: 18; and (b) a small interfering RNA molecule (siRNA) comprising a sense strand and an antisense strand, wherein the sense strand comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end and the antisense strand comprises 5'- usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO:6),44178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202wherein a, c, g, and u are 2'-O-methyladenosine-3 '-phosphate, 2'-0-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-0-methyluridine-3 '-phosphate, respectively;Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;(Agn) is adenosine-glycol nucleic acid (GNA);s is a phosphorothioate linkage; andL is2. A small interfering RNA molecule (siRNA) for use in a method of treating hepatitis B virus (HBV) infection in a subject having a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the method comprising administering to the subject:(a) an antibody comprising a light chain amino acid sequence according to SEQ ID NO: 19 and a heavy chain amino acid sequence according to SEQ ID NO: 18; and (b) a siRNA comprising a sense strand and an antisense strand, wherein the sense strand comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end and the antisense strand comprises 5'-usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO: 6),178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202wherein a, c, g, and u are 2'-O-methyladenosine-3 '-phosphate, 2'-0-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-0-methyluridine-3 '-phosphate, respectively;Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;(Agn) is adenosine-glycol nucleic acid (GNA);s is a phosphorothioate linkage; andL is3. A method of treating hepatitis B virus (HBV) infection in a subject having a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the method comprising administering to the subject:(a) an antibody comprising a light chain amino acid sequence according to SEQ ID NO: 19 and a heavy chain amino acid sequence according to SEQ ID NO: 18; and (b) a small interfering RNA molecule (siRNA) comprising a sense strand and an antisense strand, wherein the sense strand comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end and the antisense strand comprises 5'- usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO:6),178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202wherein a, c, g, and u are 2'-O-methyladenosine-3 '-phosphate, 2'-0-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-0-methyluridine-3 '-phosphate, respectively;Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;(Agn) is adenosine-glycol nucleic acid (GNA);s is a phosphorothioate linkage; andL is4. A method of reducing the serum HBsAg level in a subject, wherein the subject has a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the method comprising administering to the subject:(a) an antibody comprising a light chain amino acid sequence according to SEQ ID NO: 19 and a heavy chain amino acid sequence according to SEQ ID NO: 18; and (b) a small interfering RNA molecule (siRNA) comprising a sense strand and an antisense strand, wherein the sense strand comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end and the antisense strand comprises 5'- usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO:6),47178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202wherein a, c, g, and u are 2'-O-methyladenosine-3 '-phosphate, 2'-0-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-0-methyluridine-3 '-phosphate, respectively;Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;(Agn) is adenosine-glycol nucleic acid (GNA);s is a phosphorothioate linkage; andL is5. A method of reducing or inhibiting Hepatitis B virus (HBV) replication in a subject, wherein the subject has a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the method comprising administering to the subject:(a) an antibody comprising a light chain amino acid sequence according to SEQ ID NO: 19 and a heavy chain amino acid sequence according to SEQ ID NO: 18; and (b) a small interfering RNA molecule (siRNA) comprising a sense strand and an antisense strand, wherein the sense strand comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end and the antisense strand comprises 5'- usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO:6),178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202wherein a, c, g, and u are 2'-O-methyladenosine-3 '-phosphate, 2'-0-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-0-methyluridine-3 '-phosphate, respectively;Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;(Agn) is adenosine-glycol nucleic acid (GNA);s is a phosphorothioate linkage; andL is6. The antibody or siRNA for use or method of any one of embodiments 1- 5, wherein the light chain CDRL1, CDRL2, and CDRL3 comprise or consist of the amino acid sequences according to KLGNKN (SEQ ID NO: 12), EVK (SEQ ID NO: 13) or VIYEVKYRP (SEQ ID NO: 14), and QTFDSTTVV (SEQ ID NO:52), respectively.7. The antibody or siRNA for use or method of any one of embodiments 1- 6, wherein the heavy chain CDRH1, CDRH2, and CDRH3 comprise or consist of the amino acid sequences according to GRIFRSFY (SEQ ID NO: 8), NQDGSEK (SEQ ID NO: 9) or INQDGSEK (SEQ ID NO: 10), and AAWSGNSGGMDV (SEQ ID NO: 11), respectively.8. The antibody or siRNA for use or method of any one of embodiments 1- 7, wherein the light chain variable domain (VL) comprises or consists of the amino acid sequence according to SEQ ID NO: 17.49178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.452029. The antibody or siRNA for use or method of any one of embodiments 1- 8, wherein the heavy chain variable domain (VH) comprises or consists of the amino acid sequence according to SEQ ID NO: 16.10. The antibody or siRNA for use or method of any one of embodiments 1- 9, wherein the L is conjugated to the siRNA as shown in the following structure:wherein X is O.11. The antibody or siRNA for use or method of any one of embodiments 1-10, wherein the subject has a serum HBsAg level of less than 1000 lU / mL (< 1000 lU / mL) before treatment.12. The antibody or siRNA for use or method of any one of embodiments 1-10, wherein the subject has a serum HBsAg level of greater than 1000 lU / mL (> 1000 lU / mL) before treatment.13. The antibody or siRNA for use or method of any one of embodiments 1- 12, wherein the serum HBsAg level before treatment is the most recent serum HBsAg measurement prior to the first administration of the antibody and the siRNA.14. The antibody or siRNA for use or method of any one of embodiments 1- 13, wherein the serum HBsAg level before treatment is measured no more than 6 weeks prior to the first administration of the antibody and the siRNA.15. The antibody or siRNA for use or method of any one of embodiments 1- 14, wherein the serum HBsAg level is measured by an electrochemical immunoassay.50178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520216. The antibody or siRNA for use or method of any one of embodiments 1-14, wherein the serum HBsAg level is measured by a chemiluminescent microparticle immunoassay.17. The antibody or siRNA for use or method of any one of embodiments 1-16, further comprising administering a pegylated interferon alpha (PEG-IFNa) to the subject.18. The antibody or siRNA for use or method of embodiment 17, wherein the pegylated interferon alpha is peginterferon-a-2a (PEG-IFNa-2a).19. The antibody or siRNA for use or method of any one of embodiments 1-18, further comprising administering a nucleos(t)ide reverse transcriptase inhibitor (NRTI) to the subject.20. The antibody or siRNA for use or method of embodiment 19, wherein the NRTI is tenofovir, tenofovir disoproxil fumarate (TDF), tenofovir disoproxil (TD), entecavir, lamivudine, or adefovir, or any combination thereof.21. The antibody or siRNA for use or method of embodiment 19, wherein the NRTI is tenofovir, tenofovir disoproxil fumarate (TDF), or tenofovir disoproxil (TD).22. The antibody or siRNA for use or method of any one of embodiments 1- 21, wherein the antibody is administered to the subject every four weeks.23. The antibody or siRNA for use or method of any one of embodiments 1- 22, wherein the antibody is administered to the subject at a dose of from 200 mg to 400 mg.24. The antibody or siRNA for use or method of any one of embodiments 1-22, wherein the antibody is administered to the subject at a dose of 300 mg.25. The antibody or siRNA for use or method of any one of embodiments 1- 24, wherein the antibody is administered to the subject by subcutaneous injection.26. The antibody or siRNA for use or method of any one of embodiments 1- 25, wherein the antibody is administered to the subject for up to 44 weeks.27. The antibody or siRNA for use or method of any one of embodiments 1-25, wherein the antibody is administered to the subject for 44 weeks.51178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520228. The antibody or siRNA for use or method of any one of embodiments 1-25, wherein the antibody is administered to the subject for at least 44 weeks.29. The antibody or siRNA for use or method of any one of embodiments 1- 28, wherein the siRNA is administered to the subject every four weeks.30. The antibody or siRNA for use or method of any one of embodiments 1- 29, wherein the siRNA is administered to the subject at a dose of from 100 mg to 300 mg.31. The antibody or siRNA for use or method of any one of embodiments 1-29, wherein the siRNA is administered to the subject at a dose of 200 mg.32. The antibody or siRNA for use or method of any one of embodiments 1- 31, wherein the siRNA is administered to the subject by subcutaneous injection.33. The antibody or siRNA for use or method of any one of embodiments 1- 32, wherein the siRNA is administered to the subject for up to 44 weeks.34. The antibody or siRNA for use or method of any one of embodiments 1-32, wherein the siRNA is administered to the subject for 44 weeks.35. The antibody or siRNA for use or method of any one of embodiments 1-32, wherein the siRNA is administered to the subject for at least 44 weeks.36. The antibody or siRNA for use or method of any one of embodiments 17-35, wherein the PEG-IFNa is administered to the subject every week.37. The antibody or siRNA for use or method of any one of embodiments 17-36, wherein the PEG-IFNa is administered to the subject at a dose of 180 mcg.38. The antibody or siRNA for use or method of any one of embodiments 17-37, wherein the PEG-IFNa is administered to the subject by subcutaneous injection.39. The antibody or siRNA for use or method of any one of embodiments 17-38, wherein the PEG-IFNa is administered to the subject for up to 44 weeks.40. The antibody or siRNA for use or method of any one of embodiments 17-38, wherein the PEG-IFNa is administered to the subject for 44 weeks.41. The antibody or siRNA for use or method of any one of embodiments 17-38, wherein the PEG-IFNa is administered to the subject for at least 44 weeks.52178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520242. The antibody or siRNA for use or method of any one of embodiments 1- 41, wherein the subject has a serum HBsAg level of less than 0.05 lU / mL (< 0.05 lU / mL) after a final administration of the antibody and the siRNA.43. The antibody or siRNA for use or method of any one of embodiments 1- 42, wherein the subject has a serum HBsAg level of less than 0.05 lU / mL (< 0.05 lU / mL) after treatment for 44 weeks.44 The antibody or siRNA for use or method of any one of embodiments 1- 43, wherein the subject has an anti-HBs level of greater than 10 mIU / mL (> 10 mIU / mL) after a final administration of the antibody and the siRNA.45. The antibody or siRNA for use or method of any one of embodiments 1- 44, wherein the subject has an anti-HBs level of greater than 10 mIU / mL (> 10 mIU / mL) after treatment for 44 weeks.46. The antibody or siRNA for use or method of any one of embodiments 1- 45, wherein the subject has an anti-HBs level of greater than 100 mIU / mL (> 100 mIU / mL) after treatment for 44 weeks.47. The antibody or siRNA for use or method of any one of embodiments 1- 46, wherein the subject has chronic HBV.48. The antibody or siRNA for use or method of any one of embodiments 1- 47, wherein the subject is HBeAg-negative.49. The antibody or siRNA for use or method of any one of embodiments 1-47, wherein the subject is HBeAg-positive.50. The antibody or siRNA for use or method according to any one of embodiments 1-49, wherein the subject has hepatitis D virus (HDV) infection.51. An antibody and an siRNA for use in the method according to any one of embodiments 3-50.52. Use of an antibody and an siRNA in the manufacture of a medicament for use in the method according to any one of embodiments 3-50.53. Use of an antibody in the manufacture of a first medicament; and use of an siRNA in the manufacture of a second medicament; wherein the first and second53178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202medicaments are to be used in a combination therapy according to the method of any one of embodiments 3-50.54. An antibody; an siRNA; and a NRTI; for use in the method according to any one of embodiments 3-50.55. Use of an antibody; an siRNA; and a NRTI; in the manufacture of a medicament for use in the method according to any one of embodiments 3-50.56. Use of an antibody in the manufacture of a first medicament; use of an siRNA in the manufacture of a second medicament; and use of a NRTI in the manufacture of a third medicament; wherein the first, second, and third medicaments are to be used in a combination therapy according to the method of any one of embodiments 3-50.57. An anti-HBV antibody; an siRNA; and a PEG-IFNa; for use in the method according to any one of embodiments 3-50.58. Use of an anti-HBV antibody; an siRNA; and a PEG-IFNa; in the manufacture of a medicament for use in the method according to any one of embodiments 3-50.59. Use of an anti-HBV antibody in the manufacture of a first medicament; use of an siRNA in the manufacture of a second medicament; and use of a PEG-IFNa in the manufacture of a third medicament; wherein the first, second, and third medicaments are to be used in a combination therapy according to the method of any one of embodiments 3-50.60. An anti-HBV antibody; an siRNA; a PEG-IFNa; and a NRTI; for use in the method according to any one of embodiments 3-50.61. Use of an anti-HBV antibody; an siRNA; a PEG-IFNa; and a NRTI; in the manufacture of a medicament for use in the method according to any one of embodiments 3-50.62. Use of an anti-HBV antibody in the manufacture of a first medicament; use of an siRNA in the manufacture of a second medicament; use of a PEG-IFNa in the manufacture of a third medicament; and use of a NRTI in the manufacture of fourth54178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202medicament; wherein the first, second, third, and fourth medicaments are to be used in a combination therapy according to the method of any one of embodiments 3-50.VI. ExamplesEXAMPLE 1CLINICAL EVALUATION OF THE SAFETY, TOLERABILITY, AND EFFICACY OF COMBINATION THERAPY REGIMENS IN SUBJECTS WITH CHRONIC HEPATITIS B VIRUS INFECTION

[0122] The safety, tolerability, and efficacy of tobevibart and elebsiran were evaluated in a non -randomized, parallel assignment, open-label Phase 2 clinical trial. Tobevibart is an investigational engineered human monoclonal antibody targeting the conserved antigenic loop of HBsAg, and elebsiran is an investigational siRNA targeting the HBx region of the HBV genome. Tobevibart and elebsiran have complimentary antiviral and immunomodulatory effects that may achieve functional cure without or with PEG-IFNa (see Lempp FA, et al. J Hepatol. 2023, 79(5): 1129-1138; Gane E, J Hepatol. 2023, 79(4):924-932).Study Subjects

[0123] Subjects that were eligible for inclusion in the study were adults 18 years to 65 years of age, having chronic HBV infection for > 6 months and on NRTI therapy for > 2 months at the time of screening.

[0124] Exclusion criteria included: (1) any clinically significant chronic or acute medical condition that makes the participant unsuitable for participation; (2) significant fibrosis or cirrhosis; (3) history or evidence of drug or alcohol abuse; (4) history of chronic liver disease from any cause other than chronic HBV infection; (5) history of hepatic decompensation; (6) history of anaphylaxis; (7) history of allergic reactions, hypersensitivity, or intolerance to monoclonal antibodies, antibody fragments, or any excipients of tobevibart; (8) history of immune complex disease; and (9) history of known contraindication to any interferon product.55178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202Study Design

[0125] Table 3 shows the study design.Table 3, Study design.56178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202Endpoints

[0126] Outcome measures included: (1) Proportion of participants with treatment-emergent adverse events (TEAEs), up to 110 weeks; (2) Proportion of participants with serious adverse events (SAEs), up to 116 weeks; (3) Proportion of participants with hepatitis B surface antigen (HBsAg) loss (defined as undetectable serum HBsAg) at end of treatment, up to 48 weeks; (4) Proportion of participants with serum HBsAg loss (defined as undetectable serum HBsAg) at 24 weeks post-end of treatment, up to 72 weeks; (5) Absolute serum HBsAg and change from baseline across all timepoints in the study, up to 110 weeks; (6) Nadir and maximum reduction of serum HBsAg from baseline, up to 110 weeks; (7) Proportion of participants achieving sustained suppression of HBV DNA (< lower limit of quantification (LLOQ) for > 24 weeks after discontinuation of all treatment, including NRTIs), up to 110 weeks; (8) For hepatitis B e-antigen (HBeAg)-positive participants: Proportion of participants with HBeAg loss (undetectable HBeAg) and / or anti-HBe seroconversion at any timepoint, up to 110 weeks; (9) For HBeAg-positive participants: Time to HBeAg loss (undetectable HBeAg) and / or anti-HBe seroconversion, up to 110 weeks; (10) Cmax, up to 110 weeks; (11) Clast, up to 110 weeks; (12) Tmax, up to 110 weeks; (13) Tiast, up to 110 weeks; (14) AUCinf, up to 110 weeks; (14) AUCiast, up to 110 weeks; (15) %AUCexp, up to 110 weeks; (16) ti / 2, up to 110 weeks; (17) Az, up to 110 weeks; (18) Vz / F, up to 110 weeks; (19) CL / F, up to 110 weeks; (20) Number of participants with57178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202incidence and titers of anti-drug antibody (ADA) (if applicable) to tobevibart, up to 110 weeks; (21) Proportion of participants meeting criteria for nucleotide reverse transcriptase inhibitors (NRTI) discontinuation, up to 60 weeks; (22) Proportion of participants meeting criteria for NRTI retreatment, up to 110 weeks; (23) Proportion of participants achieving undetectable HBsAg and sustained suppression of HBV DNA [below the LLOQ, target not detected (TND)] > 24 weeks after discontinuation of all treatment, including NRTIs, up to 110 weeks; (24) Proportion of participants with serum HBsAg < 10 lU / mL at end of treatment, up to 48 weeks; (25) Proportion of participants with serum HBsAg < 10 lU / mL at 24 weeks post-end of treatment, 48 weeks treatment + 24 weeks post-end of treatment, up to 72 weeks; (26) Proportion of participants with anti-HBs seroconversion, up to 110 weeks; (27) Time to achieve nadir of serum HBsAg, up to 110 weeks; and (28) Time to achieve serum HBsAg loss, up to 110 weeks.Results

[0127] Part of the study is evaluating 24- and 48-week regimens of tobevibart and elebsiran with or without pegylated interferon alfa-2a (PEG-IFNa) for the treatment of chronic HBV infection (FIG. 1). Available end of treatment (EOT) data are reported for the 48-week regimens.

[0128] Participants received 44-48 weeks of tobevibart monotherapy (Cohort lb), tobevibart + elebsiran (Cohort 7a), or tobevibart + elebsiran + PEG-IFNa (Cohort 2c). Tobevibart, elebsiran, and PEG-IFNa were administered at 300 mg every 4 weeks (Q4W), 200 mg Q4W, and 180 pg weekly, respectively. "Baseline" is defined as the most recent non-missing (scheduled or unscheduled) measurement prior to the first dose of study treatment. Primary endpoints included treatment-emergent adverse events (TEAEs), serious TEAEs, and HBsAg seroclearance at EOT. Secondary endpoints included anti-HBs seroconversion (anti-HBs > 10 mIU / mL). Participants will also be monitored for post-treatment responses.

[0129] Serum HBsAg levels were measured prior to treatment and EOT (44-48 weeks after the first dose of the study treatment). "Baseline serum HBsAg" is defined as the most recent non-missing (scheduled or unscheduled) HBsAg measurement prior to 58178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202the first dose of study treatment. Baseline serum HBsAg levels were measured at most 6 weeks prior to dosing. Serum HBsAg was quantified using the Abbott Architect or Roche Cobas. HBsAg seroclearance or loss is defined as serum HBsAg < 0.05 lU / mL (LLOQ, lower limit of quantification).

[0130] Anti-HBs seroconversion is defined as anti-HBs antibody levels > 10 mIU / mL. Anti-HBs levels were determined using a Roche Elecsys Anti-HBs kit on the cobas8000 e801 module. A tobevibart-binding blocker was added to samples prior to analysis, preventing assay interference by tobevibart.

[0131] Baseline characteristics were generally balanced across treatment groups (Table 4).Table 4, Participant demographic and baseline characteristics.59178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202<<< < >pegylated interferon alpha; SD, standard deviation.aEOT data available for n = 27 / 50 participants enrolled.

[0132] All participants in the tobevibart (n=20) and tobevibart + elebsiran (n=51) cohorts, and approximately 50% (n=27 / 50) of those in the tobevibart + elebsiran + IFN cohort, have completed the EOT visit. The combination of tobevibart + elebsiran resulted in HBsAg Loss at EOT without or with PEG-IFNa (FIG. 2 A). HBsAg seroclearance at EOT was achieved in 0 / 20 (0%), 8 / 51 (15.7%), and 6 / 27 (22.2%) participants receiving tobevibart, tobevibart + elebsiran, or tobevibart + elebsiran + IFN, respectively (Table 6; FIG. 2A). Serum HBsAg loss at EOT was similar for tobevibart + elebsiran with or without PEG-IFNa (Table 6; FIG. 2A, left panel). Higher HBsAg seroclearance rates were observed in participants with lower baseline HBsAg, with the highest rate of 45.5% (5 / 11) observed in those with baseline HBsAg < 1,000 lU / mL who received tobevibart + elebsiran + IFN (Table 5; FIG. 2A, right panel, to FIG. 2F). Tobevibart alone or in combination with elebsiran produced similar rates of anti-HBs development, and the combination of tobevibart + elebsiran + PEG-IFNa yielded the highest antibody levels (Table 6; FIG. 3, FIG. 4). Serum HBsAg loss at EOT was associated with the development of anti-HBs antigen (FIG. 5). All participants with serum HBsAg loss in the tobevibart + elebsiran + PEG-IFNa group achieved anti-HBs positivity (FIG. 5).Table 5, HBsAg seroclearance and seroconversion at end of treatment (EOT) by cohort.60178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202< ><>< ><>< ><>< ><>1. Baseline serum HBsAg range of those achieving HBsAg seroclearance: 0.42 to 1,277 ILI / mL2. Baseline serum HBsAg range of those achieving HBsAg seroclearance: 29 to 6,449 ILI / mLHBsAg seroclearance defined as serum HBsAg < 0.05 ILI / mL (lower limit of quantification)Anti-HBs seroconversion defined as anti-HBs level > 10 mlll / mLSerum HBsAg was quantified using the Abbott Architect or Roche CobasAnti-HBs levels were determined via Roche Elecsys Anti-HBs kit on the cobas8000 e801 module; a tobevibart-binding blocker was added to samples prior to analysis, preventing assay interference by tobevibart61178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202Table 6, Anti-HBs at end of treatment.<<>

[0133] A summary of adverse events (AEs) is shown in Table 7. AEs were generally mild to moderate. The most common tobevibart- or elebsiran-related AEs (headache and influenza-like illness) were generally mild-moderate and transient. PEG-IFNa-related AEs were consistent with its established safety and tolerability profile of PEG-IFNa monotherapy. TEAEs were most commonly grade 1-2 in severity, and grade >3 TEAEs were reported in 0, 2 (3.9%), and 9 (33.3%) participants receiving tobevibart, tobevibart + elebsiran, or tobevibart + elebsiran + IFN, respectively. Study drug-related serious TEAEs were reported in 2 participants in the tobevibart + elebsiran + PEG-IFNa group: one event of leukopenia considered related to PEG-IFNa, and one event of hepatitis considered related to tobevibart, elebsiran, and PEG-IFNa (both events improved without additional sequelae). No AEs leading to death were observed.Table 7, Summary of adverse events.62178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202AE, adverse event; PEG-IFNa; pegylated interferon alpha.aA participant with multiple events within a category is counted only once in that category.bEOT data available for n = 27 / 50 participants enrolled.

[0134] Table 8 shows a summary of key laboratory abnormalities. Treatment with tobevibart + elebsiran was associated with a median ALT increase of approximately 10-15 U / L from baseline. ALT, neutrophil, and platelet abnormalities were most common in the tobevibart + elebsiran + PEG-IFNa group. There were no serious sequelae associated with laboratory abnormalities.Table 8, Summary of key laboratory abnormalities.63178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202ALT, alanine aminotransferase; PEG-IFNa, pegylated interferon alpha.aN is the number of participants with at least one non-missing post-baseline assessment during the treatment period.bFor each participant, the worst assessment during the treatment period is used.

[0135] Summary: The combination of tobevibart + elebsiran, with or without PEG-IFNa, achieved serum HBsAg loss and seroconversion at EOT, particularly in participants with lower baseline HBsAg. Tobevibart and elebsiran, without or with PEG-IFNa, achieved HBsAg loss at EOT in 15.7% (8 / 51) and 22.2% (6 / 27) of participants overall, respectively, and 38.9% (7 / 18) and 45.5% (5 / 11) of participants with baseline HBsAg <1,000 lU / mL. Serum HBsAg loss was most common in those with baseline serum HBsAg <1,000 lU / mL (Tobevibart + elebsiran: 38.9% (7 / 18); Tobevibart + elebsiran + PEG-IFNa: 45.5% (5 / 11)). Anti-HBs levels >10 lU / mL were observed in all participants who achieved serum HBsAg loss in the tobevibart + elebsiran + PEG-IFNa group compared with half of the participants who achieved HBsAg loss in the tobevibart + elebsiran group. No concerning safety signals were identified, and adverse events were generally mild or moderate, with the most common tobevibart- or elebsiran-related AEs being headache and influenza-like illness. AEs and laboratory abnormalities were more frequent and severe in the tobevibart + elebsiran + PEG-IFNa group, consistent with the known safety profile of PEG-IFNa. AEs in the 64178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202tobevibart and tobevibart + elebsiran groups were generally mild or moderate, with the most common tobevibart- or elebsiran-related AEs being headache and influenza-like illness. Low rates of treatment discontinuation or interruption were observed with tobevibart and elebsiran with or without PEG-IFNa. These data and the overall risk benefit-profile support continued clinical development for chronic HBV infection.

[0136] Tobevibart in combination with elebsiran may serve as a foundational backbone for HBV functional cure regimens. Participants with low baseline HBsAg achieved the highest rates of HBsAg loss at EOT, consistent with other investigational agents being evaluated for HBV functional cure. Rates of HBsAg loss and anti-HBs antibody development at EOT with 48 weeks of tobevibart + elebsiran, with or without PEG-IFNa, are supportive of continued development in randomized studies. Follow-up is ongoing to determine EOT responses in the remaining participants as well as posttreatment responses, including functional cure rates after cessation of study treatment and NRTI therapy.

[0137] While specific embodiments have been illustrated and described, it will be readily appreciated that the various embodiments described above can be combined to provide further embodiments, and that various changes can be made therein without departing from the spirit and scope of the invention.

[0138] All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent publications referred to in this specification, or listed in the Application Data Sheet, including U.S. Provisional Patent Application No. 63 / 721,293 filed November 15, 2024, are incorporated herein by reference, in their entirety, unless otherwise stated. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments.

[0139] These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible65178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.SEQUENCES

[0140] SEQ ID NO: 1 (Hepatitis B Virus genome - NCBI Reference Sequence NC 003977.2 (GenBank Accession No. GI:21326584)) AATTCCACAACCTTCCACCAAACTCTGCAAGATCCCAGAGTGAGAGGCCTG TATTTCCCTGCTGGTGGCTCCAGTTCAGGAACAGTAAACCCTGTTCTGACTA CTGCCTCTCCCTTATCGTCAATCTTCTCGAGGATTGGGGACCCTGCGCTGAA CATGGAGAACATCACATCAGGATTCCTAGGACCCCTTCTCGTGTTACAGGC GGGGTTTTTCTTGTTGACAAGAATCCTCACAATACCGCAGAGTCTAGACTCG TGGTGGACTTCTCTCAATTTTCTAGGGGGAACTACCGTGTGTCTTGGCCAAA ATTCGCAGTCCCCAACCTCCAATCACTCACCAACCTCTTGTCCTCCAACTTG TCCTGGTTATCGCTGGATGTGTCTGCGGCGTTTTATCATCTTCCTCTTCATCC TGCTGCTATGCCTCATCTTCTTGTTGGTTCTTCTGGACTATCAAGGTATGTTG CCCGTTTGTCCTCTAATTCCAGGATCCTCAACAACCAGCACGGGACCATGCC GGACCTGCATGACTACTGCTCAAGGAACCTCTATGTATCCCTCCTGTTGCTG TACCAAACCTTCGGACGGAAATTGCACCTGTATTCCCATCCCATCATCCTGG GCTTTCGGAAAATTCCTATGGGAGTGGGCCTCAGCCCGTTTCTCCTGGCTCA GTTTACTAGTGCCATTTGTTCAGTGGTTCGTAGGGCTTTCCCCCACTGTTTGG CTTTCAGTTATATGGATGATGTGGTATTGGGGGCCAAGTCTGTACAGCATCT TGAGTCCCTTTTTACCGCTGTTACCAATTTTCTTTTGTCTTTGGGTATACATT TAAACCCTAACAAAACAAAGAGATGGGGTTACTCTCTAAATTTTATGGGTT ATGTCATTGGATGTTATGGGTCCTTGCCACAAGAACACATCATACAAAAAA TCAAAGAATGTTTTAGAAAACTTCCTATTAACAGGCCTATTGATTGGAAAGT ATGTCAACGAATTGTGGGTCTTTTGGGTTTTGCTGCCCCTTTTACACAATGT GGTTATCCTGCGTTGATGCCTTTGTATGCATGTATTCAATCTAAGCAGGCTT TCACTTTCTCGCCAACTTACAAGGCCTTTCTGTGTAAACAATACCTGAACCT TTACCCCGTTGCCCGGCAACGGCCAGGTCTGTGCCAAGTGTTTGCTGACGCA ACCCCCACTGGCTGGGGCTTGGTCATGGGCCATCAGCGCATGCGTGGAACC TTTTCGGCTCCTCTGCCGATCCATACTGCGGAACTCCTAGCCGCTTGTTTTGC TCGCAGCAGGTCTGGAGCAAACATTATCGGGACTGATAACTCTGTTGTCCTA TCCCGCAAATATACATCGTTTCCATGGCTGCTAGGCTGTGCTGCCAACTGGA TCCTGCGCGGGACGTCCTTTGTTTACGTCCCGTCGGCGCTGAATCCTGCGGA CGACCCTTCTCGGGGTCGCTTGGGACTCTCTCGTCCCCTTCTCCGTCTGCCGT TCCGACCGACCACGGGGCGCACCTCTCTTTACGCGGACTCCCCGTCTGTGCC TTCTCATCTGCCGGACCGTGTGCACTTCGCTTCACCTCTGCACGTCGCATGG AGACCACCGTGAACGCCCACCAAATATTGCCCAAGGTCTTACATAAGAGGA CTCTTGGACTCTCAGCAATGTCAACGACCGACCTTGAGGCATACTTCAAAG ACTGTTTGTTTAAAGACTGGGAGGAGTTGGGGGAGGAGATTAGGTTAAAGG TCTTTGTACTAGGAGGCTGTAGGCATAAATTGGTCTGCGCACCAGCACCATG CAACTTTTTCACCTCTGCCTAATCATCTCTTGTTCATGTCCTACTGTTCAAGC66178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202CTCCAAGCTGTGCCTTGGGTGGCTTTGGGGCATGGACATCGACCCTTATAAA GAATTTGGAGCTACTGTGGAGTTACTCTCGTTTTTGCCTTCTGACTTCTTTCC TTCAGTACGAGATCTTCTAGATACCGCCTCAGCTCTGTATCGGGAAGCCTTA GAGTCTCCTGAGCATTGTTCACCTCACCATACTGCACTCAGGCAAGCAATTC TTTGCTGGGGGGAACTAATGACTCTAGCTACCTGGGTGGGTGTTAATTTGGA AGATCCAGCGTCTAGAGACCTAGTAGTCAGTTATGTCAACACTAATATGGG CCTAAAGTTCAGGCAACTCTTGTGGTTTCACATTTCTTGTCTCACTTTTGGAA GAGAAACAGTTATAGAGTATTTGGTGTCTTTCGGAGTGTGGATTCGCACTCC TCCAGCTTATAGACCACCAAATGCCCCTATCCTATCAACACTTCCGGAGACT ACTGTTGTTAGACGACGAGGCAGGTCCCCTAGAAGAAGAACTCCCTCGCCT CGCAGACGAAGGTCTCAATCGCCGCGTCGCAGAAGATCTCAATCTCGGGAA TCTCAATGTTAGTATTCCTTGGACTCATAAGGTGGGGAACTTTACTGGGCTT TATTCTTCTACTGTACCTGTCTTTAATCCTCATTGGAAAACACCATCTTTTCC TAATATACATTTACACCAAGACATTATCAAAAAATGTGAACAGTTTGTAGG CCCACTCACAGTTAATGAGAAAAGAAGATTGCAATTGATTATGCCTGCCAG GTTTTATCCAAAGGTTACCAAATATTTACCATTGGATAAGGGTATTAAACCT TATTATCCAGAACATCTAGTTAATCATTACTTCCAAACTAGACACTATTTAC ACACTCTATGGAAGGCGGGTATATTATATAAGAGAGAAACAACACATAGCG CCTCATTTTGTGGGTCACCATATTCTTGGGAACAAGATCTACAGCATGGGGC AGAATCTTTCCACCAGCAATCCTCTGGGATTCTTTCCCGACCACCAGTTGGA TCCAGCCTTCAGAGCAAACACCGCAAATCCAGATTGGGACTTCAATCCCAA CAAGGACACCTGGCCAGACGCCAACAAGGTAGGAGCTGGAGCATTCGGGC TGGGTTTCACCCCACCGCACGGAGGCCTTTTGGGGTGGAGCCCTCAGGCTC AGGGCATACTACAAACTTTGCCAGCAAATCCGCCTCCTGCCTCCACCAATCG CCAGTCAGGAAGGCAGCCTACCCCGCTGTCTCCACCTTTGAGAAACACTCA TCCTCAGGCCATGCAGTGG

[0141] SEQ ID NO:2 (Target sequence, nucleotides 1579-1597 of NC_003977.2 (GenBank Accession No. GE21326584))GTGTGCACTTCGCTTCAC

[0142] SEQ ID NO:3 (siRNA (elebsiran), sense strand, unmodified) GUGUGCACUUCGCUUCACA

[0143] SEQ ID NO:4 (siRNA (elebsiran), antisense strand, unmodified) UGUGAAGCGAAGUGCACACUU

[0144] SEQ ID NO:5 (siRNA (elebsiran), sense strand, modified) gsusguGfcAfCfUfucgcuucacaL

[0145] SEQ ID NO:6 (siRNA (elebsiran), antisense strand, modified) usGfsuga(Agn)gCfGfaaguGfcAfcacsusu67178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202

[0146] SEQ ID NO: 7 (HBsAg S domain) MENITSGFLGPLLVLQAGFFLLTRILTIPQSLDSWWTSLNFLGGTTVCLGQNSQS PTSNHSPTSCPPTCPGYRWMCLRRFIIFLFILLLCLIFLLVLLDYQGMLPVCPLIPG SSTTSTGPCRTCMTTAQGTSMYPSCCCTKPSDGNCTCIPIPSSWAFGKFLWEWA SARFSWLSLLVPFVQWFVGLSPTVWLSVIWMMWYWGPSLYSILSPFLPLLPIFF CLWVYI

[0147] SEQ ID NO:8 (antibody (tobevibart), CDRH1)GRIFRSFY

[0148] SEQ ID NO: 9 (antibody (tobevibart), short CDRH2)NQDGSEK

[0149] SEQ ID NO: 10 (antibody (tobevibart), long CDRH2)INQDGSEK

[0150] SEQ ID NO: 11 (antibody (tobevibart), CDRH3)AAWSGNSGGMDV

[0151] SEQ ID NO: 12 (antibody (tobevibart), CDRL1)KLGNKN

[0152] SEQ ID NO: 13 (antibody (tobevibart), short CDRL2)EVK

[0153] SEQ ID NO: 14 (antibody (tobevibart), long CDRL2)VIYEVKYRP

[0154] SEQ ID NO: 15 (antibody (tobevibart), CDRL3)QTFDSTTVV

[0155] SEQ ID NO: 16 (antibody (tobevibart), VH) ELQLVESGGGWVQPGGSQRLSCAASGRIFRSFYMSWVRQAPGKGLEWVATIN QDGSEKLYVDSVKGRFTISRDNAKNSLFLQMNNLRVEDTAVYYCAAWSGNSG GMD VWGQGTT VS VS S68178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.45202

[0156] SEQ ID NO: 17 (antibody (tobevibart), VL) SYELTQPPSVSVSPGQTVSIPCSGDKLGNKNVAWFQHKPGQSPVLVIYEVKYRP SGIPERFSGSNSGNTATLTISGTQAMDEAAYFCQTFDSTTVVFGGGTRLTVL

[0157] SEQ ID NO: 18 (antibody (tobevibart), HC) ELQLVESGGGWVQPGGSQRLSCAASGRIFRSFYMSWVRQAPGKGLEWVATIN QDGSEKLYVDSVKGRFTISRDNAKNSLFLQMNNLRVEDTAVYYCAAWSGNSG GMDVWGQGTTVSVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVT VSWNSGALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNT KVDKKVEPKSCDKTHTCPPCPAPELLAGPSVFLFPPKPKDTLMISRTPEVTCVV VDVSHEDPEVI<FNWYVDGVEVHNAI<TI<PREEQYNSTYRVVSVLTVLHQDWL NGKEYKCKVSNKALPLPEEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTCL VKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRWQQGN VFSCSVLHEALHSHYTQKSLSLSPGK

[0158] SEQ ID NO: 19 (antibody (tobevibart), LC) SYELTQPPSVSVSPGQTVSIPCSGDKLGNKNVAWFQHKPGQSPVLVIYEVKYRP SGIPERFSGSNSGNTATLTISGTQAMDEAAYFCQTFDSTTVVFGGGTRLTVLGQ PKAAPSVTLFPPSSEELQANKATLVCLISDFYPGAVTVAWKADSSPVKAGVETT TPSKQSNNKYAASSYLSLTPEQWKSHRSYSCQVTHEGSTVEKTVAPTECS69178456543.1179216384.1

Claims

1. Vir Ref. P0237.WO1PCT Fox Ref. 368561.452022.CLAIMS3.That which is claimed is:

1. An antibody for use in a method of treating hepatitis B virus (HB V) infection in a subject having a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the method comprising administering to the subject:5.(a) an antibody comprising a light chain amino acid sequence according to SEQ ID NO: 19 and a heavy chain amino acid sequence according to SEQ ID NO: 18; and (b) a small interfering RNA molecule (siRNA) comprising a sense strand and an antisense strand, wherein the sense strand comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end and the antisense strand comprises 5'- usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO:6),6.wherein a, c, g, and u are 2'-O-methyladenosine-3'-phosphate, 2'-O-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-O-methyluridine-3 '-phosphate, respectively;7.Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;8.(Agn) is adenosine-glycol nucleic acid (GNA);9.s is a phosphorothioate linkage; and10.L is178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520214.

2. A small interfering RNA molecule (siRNA) for use in a method of treating hepatitis B virus (HBV) infection in a subject having a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the method comprising administering to the subject:17.(a) an antibody comprising a light chain amino acid sequence according to SEQ ID NO: 19 and a heavy chain amino acid sequence according to SEQ ID NO: 18; and (b) a siRNA comprising a sense strand and an antisense strand, wherein the sense strand comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end and the antisense strand comprises 5'-usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO: 6),18.wherein a, c, g, and u are 2'-O-methyladenosine-3'-phosphate, 2'-O-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-O-methyluridine-3 '-phosphate, respectively;19.Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;20.(Agn) is adenosine-glycol nucleic acid (GNA);21.s is a phosphorothioate linkage; and22.L is23.71178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520227.

3. A method of treating hepatitis B virus (HBV) infection in a subject having a serum HBsAg level of greater than 10 lU / mL (> 10 lU / mL) and less than 3000 lU / mL (< 3000 lU / mL) before treatment, the method comprising administering to the subject:30.(a) an antibody comprising a light chain amino acid sequence according to SEQ ID NO: 19 and a heavy chain amino acid sequence according to SEQ ID NO: 18; and (b) a small interfering RNA molecule (siRNA) comprising a sense strand and an antisense strand, wherein the sense strand comprises 5'- gsusguGfcAfCfUfucgcuucaca -3' (SEQ ID NO:5) attached to a ligand (L) at the 3' end and the antisense strand comprises 5'- usGfsuga(Agn)gCfGfaaguGfcAfcacsusu -3' (SEQ ID NO:6),31.wherein a, c, g, and u are 2'-O-methyladenosine-3'-phosphate, 2'-O-methylcytidine-3 '-phosphate, 2'-O-methylguanosine-3 '-phosphate, and 2'-O-methyluridine-3 '-phosphate, respectively;32.Af, Cf, Gf, and Uf are 2'-fluoroadenosine-3 '-phosphate, 2'-fluorocytidine-3'-phosphate, 2'-fluoroguanosine-3 '-phosphate, and 2'-fluorouridine-3 '-phosphate, respectively;33.(Agn) is adenosine-glycol nucleic acid (GNA);34.s is a phosphorothioate linkage; and35.L is36.72178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520240.

4. The antibody or siRNA for use or method according to any one of claims 1-3, wherein the light chain CDRL1, CDRL2, and CDRL3 comprise or consist of the amino acid sequences according to KLGNKN (SEQ ID NO: 12), EVK (SEQ ID NO: 13) or VIYEVKYRP (SEQ ID NO: 14), and QTFDSTTVV (SEQ ID NO:52), respectively.

5. The antibody or siRNA for use or method according to any one of claims 1-4, wherein the heavy chain CDRH1, CDRH2, and CDRH3 comprise or consist of the amino acid sequences according to GRIFRSFY (SEQ ID NO: 8), NQDGSEK (SEQ ID NO: 9) or INQDGSEK (SEQ ID NO: 10), and AAWSGNSGGMDV (SEQ ID NO: 11), respectively.

6. The antibody or siRNA for use or method according to any one of claims 1-5, wherein the light chain variable domain (VL) comprises or consists of the amino acid sequence according to SEQ ID NO: 17.

7. The antibody or siRNA for use or method according to any one of claims 1-6, wherein the heavy chain variable domain (VH) comprises or consists of the amino acid sequence according to SEQ ID NO: 16.

8. The antibody or siRNA for use or method according to any one of claims 1-7, wherein the L is conjugated to the siRNA as shown in the following structure:47.73178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520251.

52. wherein X is O.

9. The antibody or siRNA for use or method according to any one of claims 1-8, wherein the subject has a serum HBsAg level of less than 1000 lU / mL (< 1000 lU / mL) before treatment.

10. The antibody or siRNA for use or method according to any one of claims 1-8, wherein the subject has a serum HBsAg level of greater than 1000 lU / mL (> 1000 lU / mL) before treatment.

11. The antibody or siRNA for use or method according to any one of claims 1-10, wherein the serum HBsAg level before treatment is the most recent serum HBsAg measurement prior to the first administration of the antibody and the siRNA.

12. The antibody or siRNA for use or method according to any one of claims 1-11, wherein the serum HBsAg level before treatment is measured no more than 6 weeks prior to the first administration of the antibody and the siRNA.

13. The antibody or siRNA for use or method according to any one of claims 1-12, wherein the serum HBsAg level is measured by an electrochemical immunoassay.58.74178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520214. The antibody or siRNA for use or method according to any one of claims 1-12, wherein the serum HBsAg level is measured by a chemiluminescent microparticle immunoassay.

15. The antibody or siRNA for use or method according to any one of claims 1-14, further comprising administering a pegylated interferon alpha (PEG-IFNa) to the subject.

16. The antibody or siRNA for use or method according to claim 15, wherein the pegylated interferon alpha is peginterferon-a-2a (PEG-IFNa-2a).

17. The antibody or siRNA for use or method according to any one of claims 1-16, further comprising administering a nucleos(t)ide reverse transcriptase inhibitor (NRTI) to the subject.

18. The antibody or siRNA for use or method according to claim 17, wherein the NRTI is tenofovir, tenofovir disoproxil fumarate (TDF), tenofovir disoproxil (TD), entecavir, lamivudine, or adefovir, or any combination thereof.

19. The antibody or siRNA for use or method according to any one of claims 1-18, wherein the antibody is administered to the subject every four weeks.

20. The antibody or siRNA for use or method of any one of claims 1-19, wherein the antibody is administered to the subject at a dose of from 200 mg to 400 mg.

21. The antibody or siRNA for use or method according to any one of claims 1-20, wherein the antibody is administered to the subject at a dose of 300 mg.

22. The antibody or siRNA for use or method according to any one of claims 1-21, wherein the antibody is administered to the subject by subcutaneous injection.

23. The antibody or siRNA for use or method according to any one of claims 1-22, wherein the antibody is administered to the subject for up to 44 weeks, for 44 weeks, or for at least 44 weeks.71.75178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520224. The antibody or siRNA for use or method according to any one of claims 1-23, wherein the siRNA is administered to the subject every four weeks.

25. The antibody or siRNA for use or method according to any one of claims 1-24, wherein the siRNA is administered to the subject at a dose of from 100 mg to 300 mg.

26. The antibody or siRNA for use or method according to any one of claims 1-25, wherein the siRNA is administered to the subject at a dose of 200 mg.

27. The antibody or siRNA for use or method according to any one of claims 1-26, wherein the siRNA is administered to the subject by subcutaneous injection.

28. The antibody or siRNA for use or method according to any one of claims 1-27, wherein the siRNA is administered to the subject for up to 44 weeks, for 44 weeks, or for at least 44 weeks.

29. The antibody or siRNA for use or method according to any one of claims 15-28, wherein the PEG-IFNa is administered to the subject every week.

30. The antibody or siRNA for use or method according to any one of claims 15-29, wherein the PEG-IFNa is administered to the subject at a dose of 180 mcg.

31. The antibody or siRNA for use or method according to any one of claims 15-30, wherein the PEG-IFNa is administered to the subject by subcutaneous injection.

32. The antibody or siRNA for use or method according to any one of claims 15-31, wherein the PEG-IFNa is administered to the subject for up to 44 weeks, for 44 weeks, or for at least 44 weeks.

33. The antibody or siRNA for use or method according to any one of claims 1-32, wherein the subject has chronic HBV.84.76178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520234. The antibody or siRNA for use or method according to any one of claims 1-33, wherein the subject is HBeAg-negative.

35. The antibody or siRNA for use or method according to any one of claims 1-33, wherein the subject is HBeAg-positive.

36. The antibody or siRNA for use or method according to any one of claims 1-35, wherein the subject has hepatitis D virus (HDV) infection.

37. An antibody and an siRNA for use in the method according to any one of claims 3-36.

38. Use of an antibody in the manufacture of a first medicament; and use of an siRNA in the manufacture of a second medicament; wherein the first and second medicaments are to be used in a combination therapy according to the method of any one of claims 3-36.

39. An antibody; an siRNA; and a NRTI; for use in the method according to any one of claims 3-36.

40. Use of an antibody in the manufacture of a first medicament; use of an siRNA in the manufacture of a second medicament; and use of a NRTI in the manufacture of a third medicament; wherein the first, second, and third medicaments are to be used in a combination therapy according to the method of any one of claims 3-36.

41. An anti-HBV antibody; an siRNA; and a PEG-IFNa; for use in the method according to any one of claims 3-36.

42. Use of an anti-HBV antibody in the manufacture of a first medicament; use of an siRNA in the manufacture of a second medicament; and use of a PEG-IFNa in the manufacture of a third medicament; wherein the first, second, and third96.77178456543.1179216384.1Vir Ref. P0237.WO1PCT Fox Ref. 368561.4520299.medicaments are to be used in a combination therapy according to the method of any one of claims 3-36.

43. An anti-HBV antibody; an siRNA; a PEG-IFNa; and a NRTI; for use in the method according to any one of claims 3-36.

44. Use of an anti-HBV antibody in the manufacture of a first medicament; use of an siRNA in the manufacture of a second medicament; use of a PEG-IFNa in the manufacture of a third medicament; and use of a NRTI in the manufacture of fourth medicament; wherein the first, second, third, and fourth medicaments are to be used in a combination therapy according to the method of any one of claims 3-36.102.78178456543.1179216384.1

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