Assembly Biosciences Showcases New Helicase-Primase Inhibitor Data at Herpesvirus Workshop

Assembly Biosciences, Inc., a biotech firm specializing in treatments for severe viral diseases, has unveiled promising preclinical data for its investigational herpes simplex virus (HSV) portfolio at the International Herpesvirus Workshop (IHW) in Portland, Oregon. The company showcased findings related to two novel long-acting helicase-primase inhibitor candidates for recurrent genital herpes: ABI-5366 and ABI-1179.

Dr. Anuj Gaggar, Chief Medical Officer at Assembly Bio, expressed enthusiasm over the advancements of their HSV inhibitors, emphasizing the potential for these treatments to address the limitations of current therapies for recurrent genital herpes. He highlighted the significance of the data presented at IHW, noting the company's commitment to progressing these candidates and sharing more updates with the scientific community.

Recurrent genital herpes is a significant concern, with about half of those experiencing initial symptomatic infections facing three or more recurrences annually. This condition affects over four million individuals across the United States, France, Germany, Italy, Spain, and the United Kingdom. While genital herpes can be caused by HSV-1 or HSV-2, recurrences are more frequent in HSV-2 infections. Current treatment options, mainly nucleoside analogs, are only partially effective in preventing recurrences, creating a need for more effective solutions.

Assembly Bio's HSV antiviral candidates, ABI-5366 and ABI-1179, target the HSV helicase-primase complex, an enzyme complex crucial for HSV replication and not found in host cells. These candidates are designed for long-acting administration, potentially offering a more effective and durable treatment option.

A poster presentation titled "The Helicase-Primase Inhibitor ABI-5366 Is a Novel, Potent, Long-Acting Inhibitor for the Treatment of Recurrent Genital Herpes" provided key preclinical data that supported the initiation of Phase 1 clinical trials for ABI-5366. The results demonstrated that ABI-5366 exhibited potent activity against both HSV-1 and HSV-2, including various clinical isolates, while maintaining specificity for HSV. Moreover, the compound was generally non-toxic across different cell types and showed no off-target effects. The favorable safety profile was confirmed through 28-day oral toxicity studies in two species, and pharmacokinetic studies indicated the compound's potential for long-acting administration. The Phase 1a/b trial for ABI-5366 began in May 2024, with interim Phase 1a data expected in Q3 2024 and Phase 1b data anticipated in the first half of 2025.

Another presentation, encompassing both oral and poster formats, titled "Preclinical Characterization of ABI-1179, a Potent Helicase Primase Inhibitor for the Treatment of Recurrent Genital Herpes," showcased preclinical data for ABI-1179. Licensed from Gilead Sciences, Inc., ABI-1179 is a structurally distinct helicase-primase inhibitor. The compound has shown low nanomolar activity against HSV-1 and HSV-2 lab strains and clinical isolates, including those resistant to acyclovir. Additionally, ABI-1179 displayed a higher resistance barrier compared to acyclovir and demonstrated antiviral activity against certain HSV-2 strains with known resistance mutations to other helicase-primase inhibitors. Preclinical studies indicated a favorable pharmacokinetic profile that supports the possibility of once-weekly oral dosing. In a model of recurrent HSV infection, ABI-1179 significantly reduced recurrent lesion development. Assembly Bio aims to commence a Phase 1a/b first-in-human study for ABI-1179 by the end of 2024.

Assembly Biosciences plans to make these presentations accessible on its website. The investigational products ABI-5366 and ABI-1179 have not yet received global approval, and their safety and efficacy remain to be fully established.

Assembly Bio is dedicated to developing innovative therapeutics to combat serious viral diseases, improving patient outcomes worldwide. The company continues to push forward in the field of virology, driven by a team of experts committed to addressing the immense challenges posed by chronic viral infections.