SOUTH SAN FRANCISCO, Calif. — August 8, 2025 — BiotechReporter.news — Assembly Biosciences, Inc. (Nasdaq: ASMB) reported positive interim results from a Phase 1b study of ABI-5366, a long-acting herpes simplex virus (HSV) helicase-primase inhibitor, for treating HSV type 2 (HSV-2) with recurrent genital herpes.
The study showed a 94% reduction in HSV-2 shedding rate and a 98% reduction in high viral load shedding rate with a 350 mg weekly oral dose compared to placebo over 29 days. There was also a 94% reduction in genital lesion rate with the same dose. ABI-5366 was well-tolerated at oral doses up to 350 mg weekly, supporting once-weekly dosing.
Assembly Bio plans to move directly into Phase 2 clinical study preparation, expecting to start in mid-2026. Gilead Sciences, Inc. has the right to opt in to an exclusive license for further development and commercialization of the helicase-primase inhibitor program after reviewing the option data package to be delivered by Assembly Bio following completion of the Phase 1b studies.
Anuj Gaggar, MD, PhD, chief medical officer of Assembly Bio, said the data exceeded targets for antiviral activity and clinical outcomes.
Contacts:
Investor and Corporate: Shannon Ryan, SVP, Investor Relations, Corporate Affairs and Alliance Management, (415) 738-2992, investor_relations@assemblybio.com
Media: Alyssa Kuciunas, Sam Brown Healthcare Communications, (331) 481-3751, ASMBMedia@sambrown.com
Source: Assembly Biosciences, Inc.
