PHILADELPHIA, PA—Treatment with rilpivirine/emtricitabine/tenofovir DF (RPV/FTC/TDF) was noninferior to efavirenz (EFV/FTC/TDF) in treatment-naïve patients with HIV at Week 48, the first study to compare the safety and efficacy of the two single-tablet regimens directly concluded at IDWeek 2014.
“Though the number of females enrolled was small, there was no difference in rates of virologic suppression between genders,” said Catherine Creticos, MD, of the Howard Brown Health Center in Chicago, IL. The open-label STaR study also included post-hoc analyses to investigate whether outcomes and adverse events varied by gender in patients at week 96.
For the primary endpoint, proportion of subjects with HIV-1 RNA <50 copies/mL at Week 48 (12% non-inferiority margin), RPV/FTC/TDF (n=394) was noninferior to EFV/FTC/TDF (n=392) for HIV RNA <50 copies/mL (85.8% RPV/FTC/TDF vs. 81.6% EFV/FTC/TDF; difference 4.1%, 95% CI -1.1%, 9.2%) at Week 48 and also at Week 96 (77.9% vs. 72.4%; difference 5.5%, 95% CI -0.6%, 11.5%), Dr. Creticos reported.
Week 96 virologic suppression by gender, for RPV/FTC/TDF vs. EFV/FTC/TDF was 78.7% (288/366) vs. 73.6% (268/364) for males (strata adjusted difference, 5.1% [-1.1%–11.3%]) and, for females, 67.9% (19/28) vs. 57.1% (16/28; strata adjusted difference, 12.0% [-15.5%–39.5%]), with P=0.76 for testing homogeneity of response.
For adverse events (AEs) listed in the RPV and EFV prescribing information, nervous system rates were 27.0% RPV/FTC/TDF vs. 48.4% EFV/FTC/TDF in males and 28.6% vs. 35.7% in females, with dizziness and headache being the most frequently reported.
Rates of Grade 3–4 treatment-emergent AEs were 9.6% (35/366) in the RPV/FTC/TDF arm vs. 16.2% (59/364) in the EFV/FTC/TDF arm in males, and 17.9% (5/28) vs. 21.4% (6/28) in females. Rates of discontinuation due to AEs were 2.7% (10/366) vs. 11.0% (40/364) in males and 7.1% (2/28) vs. 10.7% (3/28) in females.
In the female subpopulation, lower rates of important nervous system, psychiatric, and rash AEs as well as lower rates of discontinuations due to AEs were observed in the RPV/FTC/TDF arm, Dr. Creticos said.