SOUTH SAN FRANCISCO, Calif. — October 10, 2025 — Leads & Copy — Assembly Biosciences, Inc. (Nasdaq: ASMB) presented interim Phase 1b clinical data for its long-acting herpes simplex virus (HSV) helicase-primase inhibitor candidate ABI-5366 at the 38th Congress of the International Union Against Sexually Transmitted Infections (IUSTI)- Europe in Athens, Greece. The presentation featured data from two cohorts of participants with recurrent genital herpes.
Anuj Gaggar, MD, PhD, chief medical officer of Assembly Bio, noted the potential to reduce viral shedding rates and genital lesions with a weekly oral dose of ABI-5366, highlighting its potent antiviral activity. In the 350 mg weekly dosing cohort, statistically significant reductions were observed compared to placebo for HSV type 2 (HSV-2) shedding rate (94% decrease), high viral load shedding rate (98% decrease), and genital lesion rate (94% decrease).
A monthly oral dosing regimen of ABI-5366 and weekly dosing of ABI-1179, another HSV helicase-primase inhibitor candidate, are being evaluated. Assembly Bio anticipates sharing interim data from both studies later this fall and expects to initiate Phase 2 clinical studies of ABI-5366 in mid-2026.
Assembly Bio intends to make the presentation materials available on its website. Under a collaboration agreement with Gilead Sciences, Inc. (Gilead), Gilead has the right to opt in to an exclusive license for further development and commercialization of the helicase-primase inhibitor program.
ABI-5366 and ABI-1179 are investigational product candidates whose safety and efficacy have not been established.
Contacts
Investor and Corporate:
Shannon Ryan
SVP, Investor Relations, Corporate Affairs and Alliance Management
(415) 738-2992
investor_relations@assemblybio.com
Media:
Alyssa Kuciunas
(331) 481-3751
ASMBMedia@sambrown.com
Source: Assembly Biosciences
