Enanta Pharmaceuticals, Inc. · NASDAQ:ENTA
Enanta Pharmaceuticals — Technical Presentation (September 2025)
24 slides from Enanta Pharmaceuticals's technical presentation, Sep 29, 2025
Slide 1: Phase 2b Study of Zelicapavir in High-Risk Adults: RSVHR Topline Results
Phase 2b Study of Zelicapavir in High-Risk Adults: RSVHR Topline Results September 29, 2025
Slide 2: Forward Looking Statements Disclaimer
Forward Looking Statements Disclaimer This presentation contains forward-looking statements concerning our business, operations and financial performance and condition, as well as our plans, objectives and expectations for our research and development programs, our business and the industry in which
Slide 3: Enanta Pipeline
Enanta Pipeline DISEASE TARGET DISCOVERY PRECLINICAL PHASE 1 PHASE 2 PHASE 3 MARKET Hepatitis C Virus Protease Glecaprevir* Virology: Liver Hepatitis B Virus Core EDP-514** Zelicapavir (EDP-938) Pediatrics N-Protein Respiratory Zelicapavir (EDP-938) High Risk Adults Virology: Syncytial Virus Respira
Slide 4: Zelicapavir Development Plans
Zelicapavir Development Plans: Treatment for Patients at High Risk for Severe RSV Infection Goal: Treat patients at high risk for developing severe infection leading to hospitalization or death, populations with the most significant unmet need Pediatric Well-tolerated, Infants and favorable safety
Slide 5: Clinically Meaningful Reduction in Symptom Duration of ~1 Day by Approved Antivirals
Clinically Meaningful Reduction in Symptom Duration of ~1 Day Demonstrated by Multiple Approved Antivirals Influenza SARS-CoV-2 oseltamivir1 baloxavir marboxil2 ensitrelvir3 Median days to alleviation of symptoms 8.0 1d Placebo (13%) 1d (14%) Active 6.0 1d (21%) 4.0 1.1d (33%) 2.0 7.3 6.3 5.1 4.1 3.
Slide 6: RSVHR: Zelicapavir Proof-of-Concept High-Risk Adult Study
RSVHR: Zelicapavir Proof-of-Concept High-Risk Adult Study • RSVHR is a proof-of-concept study (n=186) that was expected to show a clinically meaningful reduction in symptom duration of at least ~1 day • Totality of data, including numerous secondary endpoints, will inform the design of a Phase 3 tri
Slide 7: Phase 2b Study of Zelicapavir in High-Risk Adults: RSVHR Topline Results
Phase 2 Study of Zelicapavir in High-Risk Adults: RSVHR Topline Results A PHASE 2B, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED, STUDY TO EVALUATE EFFICACY AND SAFETY OF EDP-938 IN NON-HOSPITALIZED ADULTS WITH ACUTE RESPIRATORY SYNCYTIAL VIRUS INFECTION WHO ARE AT HIGH RISK FOR COMPLICATIONS
Slide 8: Design & Objectives
Zelicapavir Phase 2b High-Risk Adult Study: Design & Objectives First proof-of-concept Phase 2 high-risk adult study designed to give initial indication of treatment effect on time to symptom resolution • Primary Objective: Double-Blinded Treatment Phase Time to resolution of RSV 5 days 186 adults w
Slide 9: Symptom Evaluations as Measured by PROs
Zelicapavir Phase 2b High-Risk Adult Study: Symptom Evaluations as Measured by PROs RiiQTM (Respiratory Infection Intensity and Impact Questionnaire) • 5 components; 29 parameters assessed on a 4-point scale; collected daily • Resolution: all symptoms mild or absent • Complete resolution: all sympto
Slide 10: Patient Disposition
Zelicapavir Phase 2b High-Risk Adult Study: Patient Disposition Randomized (n=187) Randomized in error (n=1) Randomized and Dosed (n=186) Placebo (n=65)* Zelicapavir (n=121)* Safety Population Placebo (n=60) Zelicapavir (n=115) Efficacy Population Placebo (n=50) Zelicapavir (n=92) HR3 Population 93.
Slide 11: Baseline Characteristics (Safety & HR Population)
Zelicapavir Phase 2b High-Risk Adult Study: Baseline Characteristics (Safety & HR Population) • Baseline characteristics were balanced across treatment groups • Majority of patients (~2/3) enrolled within 48 hours of symptom onset prior to randomization Safety Population HR3 Population* Zelicapavir
Slide 12: Baseline Characteristics (Safety & HR Population)
Zelicapavir Phase 2b High-Risk Adult Study: Baseline Characteristics (Safety & HR Population) • Baseline characteristics were balanced across treatment groups Safety Population HR3 Population* Zelicapavir Placebo Zelicapavir Placebo Description (N=121) (N=65) (N=92) (N=50) CHF – n (%) 27 (22.3) 8 (1
Slide 13: Exhibited Favorable Safety Profile
Zelicapavir Phase 2b High-Risk Adult Study: Exhibited Favorable Safety Profile • Adverse events (AEs) were similar between zelicapavir dosing groups and placebo • No AEs led to treatment discontinuation or study withdrawal in zelicapavir group Zelicapavir Placebo Description (N=121) (N=65) Treatment
Slide 14: TEAEs Occurring at >2% in any Group
Zelicapavir Phase 2b High-Risk Adult Study: TEAEs Occurring at >2% in any Group • The two most common adverse events in the zelicapavir group were diarrhea and asthma Zelicapavir Placebo Preferred Term (N=121) (N=65) Diarrhea 4 (3.3) 1 (1.5) Asthma 3 (2.5) 1 (1.5) Nausea 1 (0.8) 2 (3.1) © 2025 Enant
Slide 15: Faster Time to Complete Symptom Resolution by RiiQ
Zelicapavir Phase 2b High-Risk Adult Study: Faster Time to Complete Symptom Resolution by RiiQTM • Zelicapavir resulted in faster complete symptom resolution across multiple RiiQTM measures Efficacy Population HR3 Population* 20 7.2d Median days to alleviation of symptoms (34%) 18 Placebo 3.6d 6.7d
Slide 16: Faster Time to Symptom Resolution by PGI-S
Zelicapavir Phase 2b High-Risk Adult Study: Faster Time to Symptom Resolution by PGI-S • Statistically significant 2-day faster symptom resolution by PGI-S compared to placebo Efficacy Population (p=0.0446) HR3 Population (p=0.0465) Symptoms Being Unresolved Survival Probability of RSV Time Since Fi
Slide 17: Symptom Summary for Zelicapavir Compared to Placebo
Zelicapavir Phase 2 High-Risk Adult Study: Symptom Summary for Zelicapavir Compared to Placebo Symptoms Measured by RiiQTM • Faster time to complete resolution of all RSV symptoms to absent LRTD All RSV Total RiiQTM 4 Symptoms 13 Symptoms All 29 Parameters Efficacy Population 0.5 days 2.2 days 3.6 d
Slide 18: Additional Clinical Endpoints
Zelicapavir Phase 2 High-Risk Adult Study: Additional Clinical Endpoints • Lower hospitalization rate for patients treated with zelicapavir – 5.0% (3/60) on placebo vs 1.7% (2/115) on zelicapavir – Hospitalizations due to RSV*: • Investigator attribution: 5.0% (3/60) on placebo vs. 0% (0/115) on zel
Slide 19: Virology Results for Zelicapavir Compared to Placebo
Zelicapavir Phase 2 High-Risk Adult Study: Virology Results for Zelicapavir Compared to Placebo • Larger viral load decline at the end of treatment (Day 5) – Efficacy Population: 0.6 log – HR3 population: 0.7 log • Greater proportion of patients with undetectable viral load at the end of treatment –
Slide 20: RSV PCR Viral Load for HR3 Population
Zelicapavir Phase 2b High-Risk Adult Study: RSV PCR Viral Load for HR3 Population • Viral load decline of 0.7 log at the end of treatment 1 EDP-938 (N=92) Zelicapavir (n=92) Placebo (N=50) Placebo (n=50) Baseline (+/-SE) (log10 copies/mL) LS Mean Viral Load Change from 0 Δ = -0.6 Δ = -0.7 -1 -2 Δ =
Slide 21: Time to RSV PCR Undetectable Viral Load for HR3 Population
Zelicapavir Phase 2b High-Risk Adult Study: Time to RSV PCR Undetectable Viral Load for HR3 Population • Median time to viral load undetectable was 5 days shorter for zelicapavir compared to placebo 1.0 Median (95% CI) Zelicapavir (n=92): 8.03 (7.83, 12.99) EDP-938 (N=92): 8.03 (7.83, 12.99) 0.9 Pla
Slide 22: Conclusions
Zelicapavir Phase 2b High-Risk Adult Study: Conclusions • Zelicapavir demonstrated compelling results on multiple clinically meaningful endpoints measuring different aspects of RSV disease Up to one week improvement in complete RiiQ symptom resolution Statistically significant improvement in PGI
Slide 23: Key Learnings for Phase 3
Zelicapavir Phase 2b High-Risk Adult Study: Key Learnings for Phase 3 • Identified multiple potential registrational endpoints Time to complete resolution of all 13 RSV symptoms by RiiQTM Time to complete resolution of total 29-parameter RiiQTM Time to resolution of PGI-S Hospitalization rat
Slide 24: Phase 2b Study of Zelicapavir in High-Risk Adults: RSVHR Topline Results
Phase 2b Study of Zelicapavir in High-Risk Adults: RSVHR Topline Results September 29, 2025
Enanta Pharmaceuticals — Technical Presentation (September 2025) on 6ix