HOOKIPA Pharma Inc. announced that the first person has been dosed in a Phase 1b clinical trial of HB-500, an investigational therapeutic vaccine for the treatment of HIV. As a result, HOOKIPA achieves a $5 million non-dilutive milestone payment under its collaboration and license agreement with Gilead. The Phase 1b clinical trial (NCT06430905) will evaluate the safety and tolerability, reactogenicity, and immunogenicity to repeated doses of HB-500 in participants with HIV on suppressive antiretroviral treatment.

The Phase 1b design comprises two dose escalation cohorts that will be randomized to receive HB-500 or placebo. The first participant was dosed on July 1, 2024, and enrollment is ongoing. HOOKIPA is responsible for advancing the HIV program through the completion of a Phase 1b clinical trial.

Gilead has the exclusive right to assume further development of the program thereafter. HB-500 is one of two separate developmental programs in HOOKIPA?s collaboration and license agreement with Gilead. About HB-500: HB-500 comprises two genetically engineered replicating vectors based on the arenaviruses Pichinde virus and lymphocytic choriomeningitis virus, respectively.

The HB-500 vectors have been engineered to deliver HIV antigens derived from parts of key, immunogenic regions of HIV type 1 (HIV-1) proteins that are highly conserved within HIV-1 clade B variants. The designed immunogens differ from each other by their amino acid sequence allowing for coverage of >80% of circulating HIV-1 viral variants.