Assembly Biosciences has dosed the first subject in the Phase Ia/b study’s Phase Ib portion, evaluating ABI-1179, the long-acting herpes simplex virus (HSV) helicase-primase inhibitor candidate, in individuals with recurrent genital herpes.

This segment of the trial aims to assess the antiviral activity and safety of weekly oral doses of the therapy for over a 29-day treatment period.

It will measure antiviral activity by monitoring changes in HSV type 2 shedding rate and HSV-2 DNA levels.

Clinical parameter effects, such as the number of days with lesions, will also be evaluated.

ABI-1179 has shown encouraging interim Phase Ia outcomes, indicating a pharmacokinetic (PK) profile conducive to once-weekly oral dosing.

The company is progressing ABI-5366 and ABI-1179 into Phase Ib trials, following the Phase Ia outcomes that met the company's target PK profiles.

These studies employ similar eligibility criteria and are carried out at overlapping sites.

To facilitate the concurrent trials, the company has secured an investigational new drug application clearance in the US for the therapy, allowing the expansion of the Phase Ib study.

Assembly Biosciences chief medical officer Anuj Gaggar said: “For the millions of individuals affected by recurrent genital herpes, current therapies fall short in managing the significant impact repeated outbreaks have on their lives.

“With the Phase Ib study of ABI-1179 now underway, we look forward to evaluating viral and clinical outcomes for both promising long-acting HSV investigational therapies, ABI-5366 and ABI-1179, and we remain on track for interim data from both studies in the fall of this year.”

Under the partnership involving the company and Gilead Sciences, the latter retains the option to exclusively license ABI-1179 and ABI-5366 for further development and commercialisation following the Phase Ib data package review provided by Assembly Bio.

Gilead contributed ABI-1179 to the company under this collaboration.