MedicalResearch.com Interview with:
Dr. Pedro Cahn
Chief of the infectious disease unit at Juan A. Fernandez Hospital
Buenos Aires, Argentina, and
ONCEMRK lead study investigator
MedicalResearch.com: What is the background for this study? What are the main findings?
The ONCEMRK Phase 3 study was conducted to evaluate the efficacy and safety of once-daily ISENTRESS (raltegravir) HD 1200 mg (given as two 600 mg oral tablets) compared to twice daily raltegravir 400 mg, each in combination therapy with emtricitabine plus tenofovir disoproxil fumarate in previously untreated adults with HIV-1 infection with levels of HIV-1 RNA ≥ 1,000 copies/mL.
- Week 96 data showed:
- 5 percent of the 531 patients taking once-daily raltegravir 1200 mg (2 x 600 mg) achieved viral suppression of less than 40 copies/mL of HIV-1 RNA, compared to 80.1 percent of the 266 patients taking twice-daily raltegravir 400 mg, both in combination therapy with emtricitabine plus tenofovir disoproxil fumarate, with a treatment difference of 1.4 percent.
- Increases in CD4+T-cell counts from baseline were comparable for the two treatment regimens, with an average increase of 261.6 cells/mm3 for once-daily raltegravir (1200 mg) and 262.2 cells/mm3 for twice-daily raltegravir (400 mg).
- Efficacy was consistent across a variety of patient populations, including those with high viral load at baseline (HIV-1 RNA >100,000 copies/mL).
- Treatment-emergent viral mutations leading to any drug resistance were detected in less than 1 percent of patients in both treatment arms, with 4/531 (0.8 percent) in the once-daily raltegravir (1200 mg) treatment arm, and 2/266 (0.8 percent) in the twice-daily raltegravir (400 mg) treatment arm through 96 weeks.
- The rate of discontinuation of therapy due to adverse events through 96 weeks was low (1.3 percent in patients receiving once-daily raltegravir (1200 mg) and 2.3 percent in patients receiving twice-daily raltegravir (400 mg).