---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-25-089949"
form_type: "8-K"
ticker: "ASMB"
cik: "0001426800"
company_name: "ASSEMBLY BIOSCIENCES, INC."
filed_at: "2025-06-25T23:59:59+00:00"
generated_at: "2026-05-18T19:13:31.566600+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Assembly Bio reports positive Phase 1b topline results for ABI-4334 in chronic HBV; Gilead opt-in triggered

## Summary
- Mean HBV DNA decline of 3.2 log10 IU/mL over 28 days in 400 mg cohort (2.9 logs in 150 mg cohort).
- Favorable safety: no serious AEs or discontinuations; two grade 3 lab abnormalities resolved with continued dosing.
- Half-life supports once-daily oral dosing; exposure at both doses achieved double-digit multiples over target EC50.
- Data triggers Gilead's right to opt-in for exclusive license after review of option data package.
- ABI-4334 shows potential to inhibit viral replication at 150 mg and cccDNA formation at higher doses.

## SEC filing metadata
- accession: 0000950170-25-089949
- form_type: 8-K
- ticker: ASMB
- cik: 0001426800
- company_name: ASSEMBLY BIOSCIENCES, INC.
- filed_at: 2025-06-25T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1426800/000095017025089949/0000950170-25-089949-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1426800/000095017025089949/asmb-20250625.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-25-089949
- JSON: https://secwatch.observer/filing/0000950170-25-089949.json
- Plain text: https://secwatch.observer/filing/0000950170-25-089949.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.