Update on antiretroviral therapy: the 15th CROI.

In this column, we summarize and discuss key studies, results of which you may want to consider and discuss with colleagues and patients. THERAPIES FOR INITIAL TREATMENT What Are the Optimal First-Line NRTIs? Several presentations provided important new data regarding the optimal NRTI combination as part of an initial drug regimen. These studies were presented shortly after a new iteration of the Department of Health and Human Services (DHHS) guidelines for the use of antiretroviral agents in HIV-1–infected adults and adolescents, which were posted online on January 29, 2008.1 A notable change was the demotion of the zidovudine/ lamivudine fixed-dose combination (FDC) to an “alternative” therapy and the promotion of abacavir/lamivudine (ABC/3TC) once-daily FDC to a “preferred” therapy, so clinicians still have 2 preferred choices of a fixed NRTI backbone when starting treatment. (The tenofovir/emtricitabine [TDF/FTC] FDC remains a preferred choice.) However, the revised DHHS guidelines now specifically state that abacavir is only for patients who test negative for HLA-B*5701. The guidelines also note that such patients should be warned about and monitored for an abacavir-related hypersensitivity reaction. • HEAT trial. Remarkably, just 1 week after release of these updates to the DHHS guidelines, the 48-week data from the HEAT study—a prospective, randomized study comparing the 2 preferred once-daily FDCs—were presented.2 In the HEAT study, 688 patients received either blinded ABC/3TC or TDF/FTC in combination with once-daily lopinavir/ritonavir (LPV/r) soft gel caps for 48 weeks. At baseline, the median CD4+ cell count was about 200/μL and the median HIV RNA level was 4.9 log10 copies/mL; approximately 40% of the participants had an HIV RNA level of 100,000 copies/mL or higher. Outcomes at 48 weeks are shown in Table 1.