GSK drops one of 2 maturation inhibitors in HIV pipeline

GSK’s weighty HIV pipeline just got slightly lighter as the British Big Pharma decided not to progress a once-promising candidate into late-stage trials.

The asset in question, dubbed GSK3640254, was a so-called maturation inhibitor, a type of antiretroviral medicine designed to prevent the HIV replication process by blocking key enzyme activity and causing the formation of immature virus particles. The candidate had demonstrated antiviral activity, safety and tolerability in a phase 2a study back in 2021, but the anticipated phase 2b findings never appeared.

The move to cull GSK3640254 was revealed in a presentation (PDF) to coincide with GSK’s first-quarter earnings results this morning.

The company made the decision that the candidate was not differentiated enough in the daily oral HIV market, Fierce Biotech has learned. Another limit on the drug’s potential effectiveness was its food effect, a term for the reduced effectiveness of certain drugs if taken soon after a meal.

All of GSK’s HIV assets are developed by ViiV Healthcare, its HIV unit that also lists Pfizer and Shionogi as shareholders. ViiV spoke positively about GSK3640254 back in 2021, describing phase 2a results as demonstrating the unit’s “commitment to researching and developing a broad range of innovative approaches to treating HIV.”

“Because there are no treatments available that target this specific stage of the HIV life cycle, maturation inhibitors may help meet a critical need, particularly for individuals who are treatment-experienced,” ViiV head of R&D Kimberly Smith, M.D., said at the time.

Still, Fierce Biotech understands that removing the candidate is not expected to have any wider impact on GSK’s HIV pipeline, which still includes a maturation inhibitor in the form of VH3739937, currently in phase 1. It’s joined by the HIV capsid protein inhibitors VH4004280 and VH4011499 as well as the HIV integrase inhibitor VH4524184. GSK also lists one HIV drug in phase 2 development: the broadly neutralizing antibody VH3810109, which showed promise in a midstage trial in October.

GSK and ViiV can point to other recent successes on the HIV front, with Cabenuva, a combination of the approved drugs cabotegravir and rilpivirine that is administered monthly or every other month, approved in 2021.