Assembly Biosciences, Inc. · NASDAQ:ASMB

Assembly Biosciences — Investor Presentation (September 2026)

37 slides from Assembly Biosciences's investor presentation, September 2026

  1. Slide 1: Advancing Life-Changing Therapies for Patients with Serious Diseases

    Advancing Life-Changing Therapies for Patients with Serious Diseases September 2026 ©2026 ASSEMBLY BIOSCIENCES, INC.

  2. Slide 2: Cautionary Note Regarding Forward-Looking Statements

    Cautionary Note Regarding Forward-Looking Statements The information in this presentation contains forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to materially differ. These risks and uncertainties include: Assembly Bio’s ability to rea

  3. Slide 3: Pipeline, People & Partner: Setting the Stage for Success

    Assembly Bio Pipeline, People & Partner: Setting the Stage for Success PIPELINE INCLUDES MULTIPLE CLINICAL STAGE INVESTIGATIONAL THERAPIES • Focused on areas with high unmet medical need and significant market opportunity • Three Phase 2 studies initiating across the portfolio in 2026 and early 2027

  4. Slide 4: Developing Differentiated Approaches for Treating Serious Diseases

    Developing Differentiated Approaches for Treating Serious Diseases Program Indication Mechanism Preclinical IND/CTA enabling Phase 1 Phase 2 Partner Hepatitis D NTCP Gilead ABI-6250 inhibitor opt-in rights PBC and PSC Transplant associated Gilead ABI-7272 NNPI herpesviruses opt-in rights Research pr

  5. Slide 5: Projected Clinical Milestones and Data Readouts

    Projected Clinical Milestones and Data Readouts Phase 2 initiation Phase 2 initiation expected 4Q 2026 ABI-6250 ABI-6250 expected 1Q 2027 LIVER DISEASES Data expected HDV PBC/PSC Data expected NTCP inhibitor NTCP inhibitor 4Q 2027 1H 2028 GS-1179 Advancing under collaboration with Gilead with HERPES

  6. Slide 6: Gilead Collaboration

    Gilead Collaboration OVERVIEW OPTION STRUCTURE FUTURE ECONOMICS • Long-term collaboration with Gilead • Assembly Bio primarily responsible • $75M collaboration extension entered into in October 2023 for R&D before opt-in payments due 4Q 2026, 2028 and 2030 • Brings together two teams’ knowledge • Up

  7. Slide 7: GS-1179 and GS-5366 (formerly ABI-1179 and ABI-5366)

    GS-1179 and GS-5366 (formerly ABI-1179 and ABI-5366) Long-Acting HSV Helicase-Primase Inhibitors (HPIs) for Recurrent Genital Herpes GS-1179 and GS-5366 – Phase 1b completed dosing and follow up Gilead selected GS-1179 to advance; Phase 2 anticipated by year-end 2026 7

  8. Slide 8: Genital Herpes is a Serious Condition that Impacts Millions of Individuals in the US/EU

    Genital Herpes is a Serious Condition that Impacts Millions of Individuals in the US/EU MILLIONS AFFECTED IN US/EU5 SERIOUS HEALTH IMPACTS PROLONGED PAIN AND SYMPTOMS Painful lesions, lymphadenopathy and urinary problems that can 4M+ persist 2-3 weeks6 recurrent (3+/yr) genital herpes 1,2 FREQUENT R

  9. Slide 9: Recurrent Genital Herpes: Urgent Need for Innovative Therapies

    Recurrent Genital Herpes: Urgent Need for Innovative Therapies CURRENT STANDARD OF CARE • Daily chronic suppressive therapy with LIMITED EFFICACY HIGH TRANSMISSION HIGH PILL BURDEN TREATMENT VARIABILITY viral polymerase inhibitors (e.g., acyclovir, valacyclovir) • No new therapies approved since 199

  10. Slide 10: GS-1179 & GS-5366 Phase 1b Efficacy

    GS-1179 & GS-5366 Phase 1b Efficacy: Comparisons to Historical Placebo-Controlled Phase 1b Studies1 GS-53665 GS-11796 INCREASED EFFICACY Famciclovir2 Acyclovir3 Valacyclovir3 Pritelivir4 70% 75% 80% 85% 90% 95% 100% Shedding Reduction WEEKLY REGIMEN GS-5366 GS-1179 Famciclovir Acyclovir Valacyclovir

  11. Slide 11: Valtrex Launch in HSV Shows the Market Potential of a Novel, Longer-Acting Medicine

    Valtrex Launch in HSV Shows the Market Potential of a Novel, Longer-Acting Medicine VALTREX TOOK CONSIDERABLE SHARE OVER TIME DESPITE GENERIC ACYCLOVIR AS CONVENIENCE AND ACCEPTANCE OF CHRONIC THERAPY DROVE ADOPTION Sales in $B Zovirax and Valtrex WW Sales Valtrex LOE Branded Product Sales Only 2009

  12. Slide 12: GS-1179-101 & GS-5366-101 Phase 1b Study Design

    GS-1179-101 & GS-5366-101 Phase 1b Study Design Two Separate Studies Conducted Concurrently • Double-blind, placebo-controlled sequential cohorts • All participants seropositive for HSV-2 with recurrent genital herpes • Each cohort enrolled 20 patients on active drug and 5 on placebo • Treatment per

  13. Slide 13: Executive Summary: GS-1179 and GS-5366 Showed Strong Phase 1b Antiviral Activity

    Executive Summary: GS-1179 and GS-5366 Showed Strong Phase 1b Antiviral Activity PHASE 1B TRIAL GOALS GS-1179 COHORT B1 (50 MG, QW) GS-5366 COHORT B2 (350 MG, QW) • 80 to 85% reduction in • 98% reduction in HSV-2 • 94% reduction in HSV-2 HSV-2 shedding vs placebo shedding (p<0.01) shedding (p<0.01)

  14. Slide 14: GS-1179 Phase 1b: Safety Summary – Adverse Events Cohorts B1 & B2

    GS-1179 Phase 1b: Safety Summary – Adverse Events Cohorts B1 & B2 GS-1179 GS-1179 PARAMETER 20mg weekly/PBO 50mg weekly/ PBO N=24 N=25 Subjects with any Treatment Emergent Adverse Events (TEAE) 17 (71%) 23 (92%) (max grade), N (%) Grade 1, N (%) 12 (50%) 9 (36%) Grade 2, N (%) 5 (21%) 13 (52%) Grade

  15. Slide 15: ABI-6250 Oral NTCP Inhibitor for Hepatitis D and Cholestatic Liver Diseases

    ABI-6250 Oral NTCP Inhibitor for Hepatitis D and Cholestatic Liver Diseases (CLD) Phase 2 initiation in HDV anticipated 4Q 2026 Phase 2 initiation in PBC/PSC anticipated 1Q 2027 15

  16. Slide 16: NTCP: A Shared Target Across HDV and CLD

    NTCP: A Shared Target Across HDV and CLD NTCP inhibition blocks Bloodstream HDV infection Reducing bile acid levels in hepatocyte HDV and bile ducts is linked to improved outcomes1 Hepatocyte Bile Duct Cholesterol Bile Acids NTCP inhibition blocks Approved PBC therapies (PPAR agonists) hepatic uptak

  17. Slide 17: ABI-6250 Overall Strategy: Parallel Development Strategy Across HDV and CLD

    ABI-6250 Overall Strategy: Parallel Development Strategy Across HDV and CLD Phase 2 HDV Phase 3 HDV Study Study Initiation Anticipated 4Q 2026 Data Anticipated 4Q 2027 ABI-6250 ABI-6250 Phase 1a Chronic Tox Phase 2b/3 complete complete Study in PBC Phase 2 PBC/PSC and / or PSC Study Potential for In

  18. Slide 18: ABI-6250-101 Phase 1a Study Design

    ABI-6250-101 Phase 1a Study Design SINGLE-ASCENDING DOSE MULTIPLE-ASCENDING DOSE D1 D2 D10 D1 D10 D20 CONDUCTED COHORTS CONDUCTED COHORTS N= 8 COHORT 1: 25 mg / PBO N= 8 COHORT 1: 1 mg / PBO Follow N= 8 COHORT 2: 5 mg / PBO Up Follow N= 8 COHORT 2: 0.2 mg / PBO Up N= 8 COHORT 3: 0.05 mg / PBO KEY OU

  19. Slide 19: ABI-6250 Shows PK/PD/Safety in Phase 1a to Support Phase 2

    ABI-6250 Shows PK/PD/Safety in Phase 1a to Support Phase 2 Pharmacokinetics1 Pharmacodynamics1 ABI-6250 ABI-6250 Bulevirtide Bulevirtide2 1000 1 mg 0.2 mg 0.05 mg Multiple Multiple Dose Dose Steady State Steady State Mean ABI-6250 Plasma Concentration (ng/mL) 100 100 100 Predose from Predose Δ Total

  20. Slide 20: ABI-6250 Phase 1a: Safety Data

    ABI-6250 Phase 1a: Safety Data PBO SD 5 mg SD 25 mg SD PBO MD 0.05 mg MD 0.2 mg MD 1 mg MD (N=4) (N=6) (N=6) (N=6) (N=6) (N=6) (N=6) Subjects with any TEAE, N (%) 0 4 (66.7%) 2 (33.3%) 4 (66.7%) 6 (100%) 4 (66.7%) 4 (66.7%) Grade 1, N (%) 0 4 (66.7%) 2 (33.3%) 4 (66.7%) 6 (100%) 3 (50.0%) 4 (66.7%)

  21. Slide 21: ABI-6250: Oral Hepatitis D Virus Entry Inhibitor

    ABI-6250: Oral Hepatitis D Virus Entry Inhibitor Phase 2 initiation anticipated by end of 2026 21

  22. Slide 22: Chronic HDV is a Serious Life-Threatening Disease and Major Unmet Need

    Chronic HDV is a Serious Life-Threatening Disease and Major Unmet Need with Limited Treatment Options 12 million PEOPLE ESTIMATED TO BE CHRONICALLY INFECTED WITH HDV GLOBALLY1 Considered the most severe form of chronic viral hepatitis, with more rapid progression to liver cancer and liver-related de

  23. Slide 23: Inhibition of HDV Entry by Blocking NTCP is Clinically Validated

    Inhibition of HDV Entry by Blocking NTCP is Clinically Validated to Lower Viral Load and Normalize ALT Viral Load Reductions ALT Normalization 1 1 Wedemeyer et al., NEJM 2023; 2. Windisch et al. EASL ILC 2025 ALT: alanine transaminase; NTCP: Sodium taurocholate cotransporting polypeptide 23 1. BLV i

  24. Slide 24: ABI-6250 HDV Phase 2 Design

    ABI-6250 HDV Phase 2 Design D1 W16 W48 W72 W88 PRIMARY ENDPOINT MAIN COHORT N= 20 ABI-6250 LOW DOSE Follow Up N= 20 ABI-6250 HIGH DOSE Follow Up N= 10 NO TREATMENT ABI-6250 HIGH DOSE Follow Up EXPANSION COHORT N~20-30 ABI-6250 DOSE TBD* Follow Up TRIAL CHARACTERISTICS • Open-label • Expansion cohort

  25. Slide 25: ABI-6250: Expanding Beyond HDV into Cholestatic Liver Diseases (CLD)

    ABI-6250: Expanding Beyond HDV into Cholestatic Liver Diseases (CLD) Phase 2 initiation anticipated Q1 2027 25

  26. Slide 26: PBC and PSC Share a Common Pathology of Bile Acid Accumulation

    PBC and PSC Share a Common Pathology of Bile Acid Accumulation and Progressive Liver Injury PSC PBC • Affects intrahepatic and extrahepatic • Affects intrahepatic bile ducts bile ducts PBC PSC Associated Conditions Sjogren’s Syndrome Inflammatory Bowel Disease Complications Cirrhosis, hepatocellular

  27. Slide 27: ABI-6250 Cholestatic Liver Disease Preliminary Phase 2 Design

    ABI-6250 Cholestatic Liver Disease Preliminary Phase 2 Design Basket Study Design Exploring Efficacy and Safety in PBC and PSC in a Single Protocol D1 W 12 W 16 Cohort 1 2nd line PBC N~40 ABI-6250/PBO Follow-Up Treatment PBC Sentinel Dosing N~15 Cohort 2 3rd Line PBC N~30 ABI-6250/PBO Follow-Up Trea

  28. Slide 28: ABI-6250 Represents a Multi-Billion-Dollar Opportunity Across PBC and PSC

    ABI-6250 Represents a Multi-Billion-Dollar Opportunity Across PBC and PSC PBC PSC ~$2B+ ~$1B+ U.S. estimated peak-year revenue U.S. estimated peak-year revenue POPULATION ~150,000+ diagnosed adults in the U.S. POPULATION ~30,000+ diagnosed adults in the U.S. UNMET NEED ~40% of patients fail 1st line

  29. Slide 29: ABI-4334: Next-Generation CAM for Hepatitis B

    ABI-4334: Next-Generation CAM for Hepatitis B Phase 1b topline data reported June 2025 Positioned for next-phase development upon securing partner 29

  30. Slide 30: HBV is a Major Unmet Medical Need Globally

    HBV is a Major Unmet Medical Need Globally Up to 1,100,000 people died in 20241 HBV PREVALENCE: FROM HBV-RELATED CAUSES 240M1 Treatments are life-long INHIBIT VIRUS BUT CURE RATES VERY LOW DIAGNOSED: 65M1 Opportunity to improve patient outcomes AND INCREASE NUMBER DIAGNOSED AND TREATED, with develop

  31. Slide 31: ABI-4334 is a Next-Generation Capsid Assembly Modulator

    ABI-4334 is a Next-Generation Capsid Assembly Modulator Designed to Target Both MOAs for the Class CAPSID ASSEMBLY MODULATORS (CAMs) ABI-4334 PHASE 1B PK Direct-acting antivirals with two distinct Supportive of the ability to potentially achieve mechanisms of action double-digit multiples over paEC5

  32. Slide 32: Positive Phase 1b Data: ABI-4334 Demonstrates Potent Antiviral Activity

    Positive Phase 1b Data: ABI-4334 Demonstrates Potent Antiviral Activity COHORT 1: 150 MG COHORT 2: 400 MG 1 1 Log10 change from 0 0 Log10 change from -1 -1 baseline baseline -2 -2 -3 -3 -4 -4 0 7 14 21 28 35 42 49 56 0 7 14 21 28 35 42 49 56 Days Days HBeAg-positive or -negative cHBV infected partic

  33. Slide 33: Topline Safety Data Supports Flexibility in Dose Range

    Topline Safety Data Supports Flexibility in Dose Range Placebo ABI-4334 150mg ABI-4334 400mg (N=4) (N=8) (N=8) Subjects with any TEAE (max toxicity), N (%) 2 (50%) 5 (62.5%) 6 (75%) Grade 1, N (%) 0 2 (25%) 1 (12.5%) Grade 2, N (%) 2 (50%) 2 (25%) 5 (62.5%) Grade 3, N (%) 0 1 (12.5%)* 0 Grade 4, N (

  34. Slide 34: ABI-7272: Oral Broad-Spectrum Non-Nucleoside Polymerase Inhibitor

    ABI-7272: Oral Broad-Spectrum Non-Nucleoside Polymerase Inhibitor (NNPI) for Transplant-Associated Herpesviruses IND/CTA-enabling studies 34

  35. Slide 35: Multiple Herpesviruses Can Cause Significant Morbidity and Mortality in Transplant Recipients

    Multiple Herpesviruses Can Cause Significant Morbidity and Mortality in Immunocompromised Transplant Recipients Lifelong latent infections 95,000 PATIENTS AFFECTED1 FREQUENTLY REACTIVATE DURING IMMUNOSUPPRESSION Uncontrolled viral replication AND SEVERE DISEASE DURING REACTIVATION AMONG TRANSPLANT P

  36. Slide 36: ABI-7272 is Designed to Provide Significant Innovation Over Current Standard of Care

    ABI-7272 is Designed to Provide Significant Innovation Over Current Standard of Care CONSERVED VIRAL POLYMERASES PROVIDE OPPORTUNITY FOR BROAD-SPECTRUM HERPESVIRUS INHIBITION OPPORTUNITY TO ADVANCE CURRENT STANDARD OF CARE​ • Improve efficacy and broaden spectrum of antiviral activity • Simplify tre

  37. Slide 37: Nasdaq: ASMB

    Nasdaq: ASMB ©2026 ASSEMBLY BIOSCIENCES, INC.

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