Assembly Biosciences has completed follow-up for every participant in the Phase 1b studies of ABI‑5366 and ABI‑1179, two long-acting drugs for recurrent genital herpes. The company says the full data reinforce the safety and efficacy findings it reported earlier.
The numbers (ABI‑5366, interim analysis)
The interim analysis included 50 people with HSV‑2: 40 on the drug and 10 on placebo. The shedding result beat the company’s own 80–85% target.
What makes these drugs different
Acyclovir and valacyclovir block one viral enzyme. Helicase-primase inhibitors block a different step that HSV needs to copy its DNA. Because these versions stay in the body a long time, the company is exploring weekly and even monthly dosing.
What happens next
The program is licensed to Gilead, which will set the development plan and budget for later trials. Data were presented at the ESCMID Global congress in Munich in April 2026.
These are investigational drugs. They suppress HSV but don’t remove it, and the studies so far are small.
- Assembly Biosciences: Q1 2026 results and highlights
- Clinical Trials Arena: 94% drop in viral shedding