ASMB News & Events

H.C. Wainwright analyst Patrick Trucchio reiterates a Buy rating on Assembly Biosciences (ASMB) with a $50 price target after the company announced that Gilead (GILD) exercised its option to license both of Assembly's long-acting herpes simplex virus helicase-primase inhibitors being developed for the treatment of recurrent genital HSV infection. Gilead's exclusive license de-risks Assembly's novel antiviral pipeline, the analyst tells investors in a research note. H.C. Wainwright believes Gilead's opt-in "significantly de-risks the programs and provides Assembly with a strong financial foundation to execute across its pipeline of next-generation antivirals."

Gilead (GILD) and Assembly Biosciences (ASMB), announced Gilead has exercised its combined option to exclusively license Assembly Bio's herpes simplex virus helicase-primase inhibitor programs, including long-acting investigational candidates ABI-1179 and ABI-5366 for recurrent genital herpes. These represent the first programs Gilead will advance under the ongoing Assembly Bio R&D collaboration. ABI-1179 and ABI-5366 are novel long-acting inhibitors of viral helicase-primase, an enzyme essential for herpes virus replication with the potential to improve chronic suppressive therapy for recurrent genital herpes. Positive interim Phase 1b data for ABI-5366 and ABI-1179 demonstrated strong antiviral activity and improvements in clinical outcomes, including significant reduction in virus-positive lesions. Both compounds also exhibit pharmacokinetic and safety profiles supportive of once-weekly oral dosing. Under the terms of the 2023 collaboration agreement between Gilead and Assembly Bio, Assembly Bio will receive a $35M payment for Gilead's exercise of the combined HSV program option, which comprises both ABI-5366 and ABI-1179. The $35M payment reflects a $45M option fee, net of $10M accelerated funding Assembly Bio received under a December 2024 amendment, which was creditable against future payments. Gilead will receive an exclusive license to ABI-5366 and ABI-1179 and will have the sole right and responsibility for further clinical development and commercialization of these programs. Assembly Bio remains eligible for up to $330M in regulatory and commercial milestones, as well as tiered royalties on net sales. Assembly Bio will also have the right to opt in to share 40% of all costs and profits in the United States in lieu of receiving milestones and royalties for that program in the United States after receipt of development plans and budgets from Gilead next year.

Assembly Biosciences announced interim results from two Phase 1b studies of its investigational long-acting herpes simplex virus helicase-primase inhibitors in participants seropositive for HSV type 2 with recurrent genital herpes. These interim results include the first reported Phase 1b data for ABI-1179, evaluating weekly oral dosing. For ABI-5366, the reported data is for a monthly oral dosing regimen, following the positive interim results for weekly oral dosing reported earlier this year. cohort. This reduction exceeds Assembly Bio's target for the study of an 80%-85% reduction in HSV-2 shedding rate. Further, data revealed a 91% reduction in virologically confirmed genital lesion rate compared to placebo with the 50 mg weekly dose. There was also a greater than 99% reduction in the number of samples with high viral load, a potential surrogate for HSV-2 transmission and a secondary endpoint. ABI-1179 was observed to be well-tolerated at oral doses up to 50 mg weekly and the observed pharmacokinetic profile continues to support once-weekly oral dosing regimens. In the ABI-5366 monthly dose cohort, potent antiviral activity was observed, with a 76% reduction in HSV-2 shedding rate compared to placebo over the 29-day evaluation period. The majority of positive swabs were collected in the last two weeks of the evaluation period when drug levels were declining. An 88% reduction in virologically confirmed genital lesion rate, along with an 81% reduction in the number of samples with high viral load compared to placebo, was observed. As previously reported for the 350 mg weekly dose cohort, a 94% reduction in HSV-2 shedding rate and a 97% reduction in virologically confirmed genital lesion rate compared to placebo was observed. ABI-5366 continues to be well-tolerated across all evaluated oral dosing regimens up to 350 mg weekly, and the PK profile supports both once-weekly and potentially once-monthly oral dosing regimens. Under the collaboration agreement between Assembly Bio and Gilead (GILD), Gilead has the right to opt in to an exclusive license for further development and commercialization of the helicase-primase inhibitor program, with the first option timepoint extending through the review of an option data package to be delivered by Assembly Bio following the end of the Phase 1b studies. ABI-1179 was contributed by Gilead under the collaboration between Assembly Bio and Gilead. ABI-5366 and ABI-1179 are investigational product candidates that have not been approved anywhere globally, and their safety and efficacy have not been established.