– Late-breaking oral presentation highlights interim Phase 1b data reported earlier this year for two cohorts in participants with recurrent genital herpes –  – Statistically significant reductions in HSV-2 shedding rate, high viral load shedding rate and genital lesion rate observed in the cohort evaluating 350 mg weekly oral dose compared to placebo – – Interim data evaluating a monthly dosing regimen of ABI-5366 and weekly dosing for second HSV helicase-primase inhibitor candidate ABI-1179 expected to be ...

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]

Core Insights - Assembly Biosciences, Inc. presented Phase 1a clinical and preclinical data for its herpes simplex virus helicase-primase inhibitor candidates ABI-5366 and ABI-1179 at major conferences in July 2025, indicating progress in their development [1][2][4] Group 1: Clinical Data and Presentations - Phase 1a clinical data for ABI-5366 and ABI-1179 were showcased in multiple poster presentations at the STI & HIV 2025 World Congress and the 49th Annual International Herpesvirus Workshop [1][4] - Interim proof-of-concept Phase 1b data for both candidates in participants with recurrent genital herpes is expected in fall 2025 [1] - The late-breaking poster for ABI-1179 included the first scientific presentation of its Phase 1a clinical data, showing no clinically significant food effect [2][4] Group 2: Treatment Potential and Dosing - Both candidates are designed to offer innovative treatment options, potentially allowing for once weekly or once monthly oral dosing, which would significantly reduce the treatment burden compared to current daily therapies [2] - The current standard of care for recurrent genital herpes has not seen new drug approvals in over 25 years, highlighting the need for new treatment options [10] Group 3: Preclinical Insights and Epidemiology - Additional posters reviewed preclinical studies of ABI-5366 and provided methodology for analyzing claims data on genital herpes prevalence and treatment patterns in the U.S. [3] - Epidemiological studies estimate that over four million people in the U.S. and several European countries experience recurrent genital herpes, with most individuals having multiple recurrences annually [10] Group 4: Mechanism of Action - HSV helicase-primase inhibitors target a viral enzyme complex essential for the herpes simplex virus, which has no equivalent in human hosts, suggesting a potentially superior efficacy compared to current nucleoside analog treatments [11] Group 5: Company Overview - Assembly Biosciences is focused on developing innovative small-molecule therapeutics aimed at serious viral diseases, with a commitment to improving patient outcomes [12]

Core Insights - Assembly Biosciences, Inc. presented Phase 1a clinical and preclinical data for its herpes simplex virus helicase-primase inhibitor candidates ABI-5366 and ABI-1179 at major conferences in July 2025, indicating progress in their development [1][2][4] Clinical Data - Phase 1a clinical data for ABI-5366 and ABI-1179 showed promising safety and pharmacokinetic profiles in healthy participants, supporting their advancement to Phase 1b evaluation [2][4] - Interim proof-of-concept Phase 1b data for both candidates in participants with recurrent genital herpes is expected in fall 2025 [1] Treatment Innovation - ABI-5366 and ABI-1179 have the potential for less frequent dosing, with ABI-5366 offering once monthly and ABI-1179 once weekly oral dosing, which could significantly reduce the treatment burden compared to current daily therapies [2][10] - The current standard of care for recurrent genital herpes has not seen new drug approvals in over 25 years, highlighting the need for innovative treatments [10] Preclinical Insights - Additional presentations at the STI & HIV 2025 World Congress included preclinical studies and methodologies for estimating genital herpes prevalence and treatment patterns in the U.S. [3][8] Company Background - Assembly Biosciences is focused on developing innovative small-molecule therapeutics for serious viral diseases, including herpesvirus infections [12]

Core Insights - Assembly Biosciences, Inc. has initiated a Phase 1b study for ABI-1179, a long-acting helicase-primase inhibitor targeting recurrent genital herpes, with the first participant dosed [1][2][3] - The study aims to evaluate the safety and antiviral activity of ABI-1179 over a 29-day treatment period, focusing on viral shedding rates and clinical outcomes [2][6] - ABI-1179 has shown promising interim results in Phase 1a, supporting its once-weekly oral dosing regimen [2][3] Company Developments - The Phase 1b study for ABI-1179 is running concurrently with ABI-5366, both of which have met the company's pharmacokinetic targets in earlier trials [3] - The company has received clearance for an Investigational New Drug (IND) application to expand the Phase 1b study to additional sites in the United States [3] - Interim data from both studies is expected to be reported in fall 2025 [1][3] Industry Context - Recurrent genital herpes affects millions, with current therapies being inadequate in managing the frequency and severity of outbreaks [4][9] - The standard treatment has not seen new drug approvals in over 25 years, highlighting a significant unmet need in the market [9] - Helicase-primase inhibitors like ABI-1179 represent a novel approach that may offer superior efficacy compared to existing nucleoside analogs [10]