Assembly Biosciences' Investigational Herpes Treatment Shows Safety In Healthy Participants (UPDATED)

Editor’s Note: The title of the story has been updated to reflect the accuracy of the data

Assembly Biosciences, Inc. ASMB released interim pharmacokinetic (PK) and safety results from healthy participants in the Phase 1a portion of its ongoing Phase 1a/b study of ABI-5366, an investigational long-acting herpes simplex virus (HSV) helicase-primase inhibitor candidate for recurrent genital herpes.

Due to its extended PK profile, ABI-5366 was well-tolerated and showed a favorable safety profile with exposure of up to 70 days.

Also Read: GSK Halts Herpes Simplex Virus Vaccine Development, Clears Path For Other Contenders Like Moderna, BioNTech.

Single doses of ABI-5366 at dose levels reached in Phase 1a surpassed Assembly Bio’s target plasma concentrations for antiviral efficacy, a target established from PK modeling and projected to reach increased efficacy compared to approved therapies.

ABI-5366’s half-life across the doses evaluated to date of approximately 20 days when dosed orally supports the company’s once-weekly oral dosing target and the evaluation of a once-monthly oral dosing profile.

“With the exceptional oral half-life of ABI-5366, we look forward to exploring its potential for both once-weekly and once-monthly oral dosing. To that end, we initiated screening for the Phase 1b portion of the study in participants with recurrent genital herpes and expect to report interim results in the first half of 2025,” said Jason Okazaki, CEO of Assembly Bio.

ABI-5366 was well-tolerated, and a favorable safety profile was observed with exposure of up to 70 days.

Treatment-emergent adverse events (AEs) were mild to moderate in intensity and considered not related to study treatment by the study investigators; there were no serious AEs in any dose arm.

Interim results exceeded Assembly Bio’s objectives for this Phase 1a study and support ABI-5366’s progression into Phase 1b.

Assembly Bio has initiated screening for Part B (Phase 1b) in participants seropositive for HSV-2 with recurrent genital herpes, which will evaluate multiple ascending doses of ABI-5366.

Part B of the study will evaluate weekly and monthly oral regimens of ABI-5366 over a 29-day treatment interval in four cohorts.

In addition to assessing safety, tolerability and PK, Part B will also evaluate antiviral activity by assessing changes in viral parameters.

Price Action: ASMB stock is down 9.42% at $17.60 at last check Monday.

Photo via Shutterstock

Read Next:

• Biohaven Stock Spikes After Drug Candidate To Treat Rare Neurodegenerative Disease Shows Promise.