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Assembly Biosciences Reports Positive Interim Results from Phase 1b Clinical Study of Long-Acting Helicase-Primase Inhibitor Candidate ABI-5366 Showing Reductions in Viral Shedding Rate and Genital Lesion Rate in Recurrent Genital Herpes

Core Insights - Assembly Biosciences, Inc. announced positive interim results from a Phase 1b study of ABI-5366, showing significant reductions in HSV-2 shedding and genital lesions in participants with recurrent genital herpes [1][4][21] Antiviral Activity - A 94% reduction in HSV-2 shedding rate was observed compared to placebo, exceeding the company's target of 80%-85% [2][12] - A 94% reduction in genital lesion rate was also noted, alongside a 98% reduction in high viral load shedding rate [2][12] Safety and Tolerability - ABI-5366 was well-tolerated at oral doses up to 350 mg weekly, with a favorable safety profile [3][13] - The proportion of participants reporting treatment-emergent adverse events was similar between ABI-5366 and placebo recipients [14] Clinical Development Plans - The company plans to move directly into Phase 2 clinical study preparation, expecting to initiate these studies in mid-2026 [4][3] - Ongoing cohorts are evaluating a monthly dosing regimen for ABI-5366 [4][18] Collaboration and Future Studies - Under a collaboration agreement with Gilead Sciences, Gilead has the option to opt in for exclusive licensing of the helicase-primase inhibitor program after reviewing data from the Phase 1b studies [5][6] - Interim data from another candidate, ABI-1179, is expected to be shared in the fall of this year [4]