Merck announced results from its first large study evaluating Isentress (raltegravir) regimen against two protease inhibitor regimens in previously untreated adults with HIV-1. The company presented the new data at the 21st Conference on Retroviruses and Opportunistic Infections (CROI).
Isentress is Merck’s integrase inhibitor indicated in combination with other antiretroviral agents intended for the treatment of HIV-1 infection in adult patients. The indication is based on three double-blind studies where plasma HIV-1 RNA levels were analyzed.
The drug was evaluated in the 96 week, open-label AIDS Clinical Trials Group (ACTG) 5257 involving 1,809 patients. ACTG 5257 is the first large, well-powered study to compare raltegravir against protease inhibitor-based treatments regimens in treatment-naïve population. In the study, patients were randomized to take atazanavir/r (300 mg/100mg once daily), ISENTRESS (400 mg twice daily), or darunavir/r (800 mg once daily). Patients also received emtricitabine/tenofovir disoproxil fumarate (200/300 mg once daily).
Ninety-two percent of patients completed 96 weeks of the study. Results showed that equivalent rates of virologic control were reached for all regimens, with all three achieving high and equal levels of efficacy. The Isentress and darunavir/r regimens showed superiority to the atazanavir/r regimen when it came to the co-primary endpoint of failure due to tolerability. The Isentress regimen was also shown superior to the other two regimens on the key secondary endpoint of the combination of virologic failure and tolerability failure.
Dr. Randi Leavitt, executive director of Infectious Diseases at Merck Research Laboratories and co-author of the ACTG 5257 study, said, “These findings provide additional evidence of the efficacy and tolerability of ISENTRESS in a diverse population of treatment-naïve adults with HIV-1. We want to acknowledge the patients who participated in this study, the ACTG and the trial investigators for this important contribution to the therapeutic evaluation of medicines used to manage the consequences of HIV infection.”