Two One-Pill Regimens Face Off

Now that three single-tablet regimens are available for HIV treatment, competition for the “best” option is intense. In phase III trials comparing efavirenz/FTC/tenofovir (Atripla) and elvitegravir/cobicistat/FTC/tenofovir (Stribild), the two regimens were equally safe and efficacious at week 48 (JW AIDS Clinical Care Jul 9 2012). Longer-term results from one of these trials are now available. The study was sponsored by the maker of elvitegravir/cobicistat/FTC/tenofovir.

Seven hundred treatment-naive HIV-infected patients with genotype-confirmed viral susceptibility to efavirenz, tenofovir, and FTC were randomized to receive either elvitegravir/cobicistat/FTC/tenofovir or efavirenz/FTC/tenofovir along with a placebo version of the other. At week 96, the rates of virologic suppression were similar between groups (84% for elvitegravir/cobicistat/FTC/tenofovir and 82% for efavirenz/FTC/tenofovir), as were the rates of virologic failure (6% and 8%). CD4-cell counts increased similarly in the groups.

Overall rates of adverse events were also comparable, with nausea more common in the elvitegravir/cobicistat/FTC/tenofovir group, neuropsychiatric events more common in the efavirenz/FTC/tenofovir group, and rates of treatment-limiting side effects similar between groups (5% and 7%, respectively). Treatment-limiting renal toxicity from cobicistat was seen in two patients during the second 48 weeks of treatment.

Overall rates of genotypic resistance in patients with virologic failure were similar; most participants with failure on elvitegravir/cobicistat/FTC/tenofovir had developed integrase-resistance mutations, and most of those with failure on efavirenz/FTC/tenofovir had the K103N nonnucleoside reverse transcriptase inhibitor–resistance mutation.