Assembly Biosciences, Inc. · NASDAQ:ASMB

Assembly Biosciences — Technical Presentation (October 2025)

15 slides from Assembly Biosciences's technical presentation, October 2025

  1. Slide 1: Safety, Pharmacokinetics and Antiviral Activity of ABI-5366: Phase 1b Interim Analysis

    Safety, Pharmacokinetics and Antiviral Activity of ABI-5366, a Novel, Oral, Long-Acting HSV Helicase-Primase Inhibitor in Subjects with Recurrent Genital Herpes: Interim Analysis from a Phase 1b Study Edward J. Gane1, Cory Sellwood2, Andrew Edwards3, Wayne Hayter4, Tess Tonkin5, Karen Kaluhin6, Deon

  2. Slide 2: Disclosures

    Disclosures • Mark Bloch reports support from GSK, ViiV Healthcare and Gilead Sciences for medical advisory boards, lectures and travel to scientific meetings. In addition, consulting for Assembly Biosciences who sponsored attendance at IUSTI 2

  3. Slide 3: Introduction

    Introduction • Approximately 520 million people aged 15-49 years worldwide are infected with herpes simplex virus type 2 (HSV-2), the primary cause of genital herpes 1,2 • Nucleoside analogue therapy requires daily administration and is suboptimal for suppression of viral transmission and disease re

  4. Slide 4: Methods

    Methods Study Design • ABI-5366-101 is a randomized, observer-blinded, placebo-controlled, Phase 1b viral shedding study • Up to 4 sequential cohorts to be enrolled evaluating multiple-dose regimens of 5366 or PBO – Each cohort to enroll 25 participants, (20 5366, 5 PBO); 29 Days of treatment, with

  5. Slide 5: Baseline Demographic and Disease Characteristics

    Results Baseline Demographic and Disease Characteristics ABI-5366 ABI-5366 Placebo QW 150/30 mg QW 350 mg QW Characteristics (n=10) (n=20) (n=20) Age, years; mean (SD) 43.1 (6.9) 39.3 (8.8) 41.7 (10.0) Sex at birth, n (%) Male 5 (50.0) 10 (50.0) 13 (65.0) Female 5 (50.0) 10 (50.0) 7 (35.0) White Rac

  6. Slide 6: Treatment-Emergent Adverse Events and Lab Abnormalities

    Results Treatment-Emergent Adverse Events and Lab Abnormalities ABI-5366 ABI-5366 150/30 mg QW/PBO QW 350 mg QW/PBO QW (n=25) (n=25) Participants with any TEAE, n (%) 23 (92.0) 22 (88.0) Subjects with any TEAE by grade, n (%) Grade 1 21 (84.0) 19 (76.0) Grade 2 7 (28.0) 10 (40.0) Grade 3 0 1 (4.0) G

  7. Slide 7: Mean Plasma Pharmacokinetic Profile and Parameters

    Results Mean Plasma Pharmacokinetic Profile and Parameters 150/30 mg QW 350 mg QW PK Parameters ABI-5366 ABI-5366 7000 After Last Dose 150/30 mg QW 350 mg QW (Day 29) (n=20) (n=20) On Treatment Off Treatment Tmax, hours, median 4.0 3.0 Mean ABI-5366 Concentration (ng/mL) 6000 t1/2, hours 501.1 (17.5

  8. Slide 8: Viral Shedding and Genital Lesions

    Results Viral Shedding and Genital Lesions ABI-5366 ABI-5366 Placebo QW 150/30 mg QW 350 mg QW Outcome Measured (n=10) (n=20) (n=20) HSV-2 Shedding Rate,a % 14.6 14.5 0.9 High Viral Load Shedding Rate,b % 11.4 9.4 0.2 Genital Lesion Rate,c % 19.7 11.8 1.3 Duration of Viral Shedding; mean (SD) days 5

  9. Slide 9: Reductions in HSV-2 Shedding and Viral Load in HSV-2 Positive Swabs

    Results Reductions in HSV-2 Shedding and Viral Load in HSV-2 Positive Swabs 1.9 log decline 20 9 95% CI (-2.7, -1.1) P<0.012 p<0.011 8 Log10 Copies of HSV DNA in Positive Swab Samples 14.6 14.5 15 Percent Shedding 7 6 10 5 5 4 3 0.9 0 2 Placebo 150/30 mg 350 mg 1Poisson regression analysis PBO 150/3

  10. Slide 10: Conclusions

    Conclusions • Treatment regimens were safe and well tolerated when administered orally as 150/30 mg/PBO QW and 350 mg/PBO QW for 29 days • The observed PK profile continues to support once-weekly dosing and the potential for once-monthly oral dosing regimens • Highly potent antiviral activity was ob

  11. Slide 11: Acknowledgments

    Acknowledgments • We express our gratitude to all the participants, investigators, and site staff who participated in the study – Study Investigators  Edward Gane (New Zealand Clinical Research, Auckland, New Zealand)​  Cory Sellwood (New Zealand Clinical Research, Christchurch, New Zealand)  And

  12. Slide 12: Back-up Slides

    O assemblybio Back-up Slides

  13. Slide 13: Figure 1. The HSV Helicase-Primase Enzyme Complex

    Figure 1. The HSV Helicase-Primase Enzyme Complex Created with Biorender.com HSV, herpes simplex virus (HSV) 13

  14. Slide 14: Treatment-Emergent Adverse Events, ≥5% in Either Cohort

    Results Treatment-Emergent Adverse Events, ≥5% in Either Cohort ABI-5366 ABI-5366 150/30 mg QW/PBO QW 350 mg QW/PBO QW (n=25) (n=25) Subjects with any TEAE, n (%) 23 (92.0%) 22 (88.0%) Upper Respiratory Tract Infection 9 (36.0%) 11 (44.0%) Headache 4 (16.0%) 3 (12.0%) Back Pain 1 (4.0%) 2 (8.0%) Dia

  15. Slide 15: Laboratory Abnormalities, ≥5% in Either Cohort

    Results Laboratory Abnormalities, ≥5% in Either Cohort ABI-5366 ABI-5366 Laboratory Abnormalities 150/30 mg QW/PBO QW 350 mg QW/PBO QW (n=25) (n=25) Number of Participants with postbaseline abnormalities 18 (72.0%) 18 (72.0%) Grade 1 14 (56.0%) 15 (60.0%) Grade 2 6 (24.0%) 5 (20.0%) Grade 3 1 (4.0%)

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