Islatravir, the first nucleoside reverse transcriptase translocation inhibitor, plus the non-nucleoside reverse transcriptase inhibitor doravirine (Pifeltro) kept viral load suppressed for 48 weeks with only a small number of study participants experiencing virological failure, researchers reported at the 23rd International AIDS Conference (AIDS 2020: Virtual). Thus, this well-tolerated two-drug regimen may offer a new simplified maintenance therapy option, reports Aidsmap.
Professor Chloe Orkin of Queen Mary University of London presented the latest findings from a phase 2b study evaluating the safety and efficacy of islatravir plus doravirine versus a three-drug regimen of doravirine, tenofovir disoproxil fumarate (TDF) and lamivudine, the drugs in the Delstrigo single-tablet regimen.
This randomised, double-blind trial enrolled 121 previously untreated people with no known antiretroviral resistance. More than 90% were men, three-quarters were white and the median age was 28 years. About a quarter had a viral load above 100,000 copies/ml at baseline.
The efficacy results from the study were presented at the International AIDS Society Conference on HIV Science last summer in Mexico City. Those results showed that the dual combination at the optimal dose (0.75mg) suppressed viral load at least as well as the three-drug regimen, with 90% versus 84% having undetectable viral load at 48 weeks.
In a related presentation, Dr Edwin DeJesus of the Orlando Immunology Centre in Florida described 48-week safety results from the same clinical trial.
Treatment was generally safe and well tolerated. Overall, side effects occurred with similar frequency in all islatravir dose groups and the Delstrigo group. In all treatment arms, adverse events were reported more often during the first 24 weeks of treatment compared with the second 24-week period, DeJesus noted.
Abstract (not available online)
Orkin C et al: Analysis of protocol defined virologic failure through week 48 from a phase 2 trial (P011) of islatravir and doravirine in treatment-naïve adults with HIV-1 infection. 23rd International AIDS Conference, abstract OAB0302, 2020.
DeJesus E et al: Islatravir safety analysis through week 48 from a phase 2 trial in treatment naive adults with HIV-1 infection. 23rd International AIDS Conference, abstract OABO305, 2020.