Objective: To evaluate the safety and efficacy of a protease inhibitor sparing, quadruple therapy (Combivir + abacavir + efavirenz) in antiretroviral treatment-naive HIV-1-infected adults.
Design: Multicenter open-label pilot study. Clinical and biological assessments were performed at baseline and at weeks 2, 4, 8, 16, 24, 32, 40, 48.
Results: Thirty-one subjects enrolled with a median baseline viral load (VL) of 4.69 log10 copies/mL and CD4 cell count of 322 cells/mm3. At week 48, 90% (intention-to-treat [ITT] switch included) and 77% (ITT switch = failure) patients had a VL <50 copies/mL. These results were similar in the population (n = 13) with a VL >100,000 copies/mL at baseline. Combivir + abacavir + efavirenz demonstrated an early antiretroviral response: 58% of patients had plasma HIV-1 RNA <50 copies/mL at week 8. Using a modified assay, the percentage of patients with VL <5 copies/mL at week 48 was 55% (17/31) and 42% (13/31) using ITT (switch included) and ITT (switch = failure), respectively. Median VL decreased by -4.0 log10 copies/mL at week 48 (ITT). Median CD4+ cell count change from baseline at week 48 was +129 cells/mm3 (ITT). Most patients experienced at least one drug-related adverse event that was not considered treatment-limiting by the investigator. There were no cases of abacavir hypersensitivity reactions.
Conclusions: Safety and efficacy results from this study demonstrated that the quadruple regimen Combivir/abacavir/efavirenz is generally safe and displays potent and durable antiretroviral activity in antiretroviral treatment-naive HIV-1-infected patients, offering a promising therapeutic option in a PI-sparing strategy.