Efavirenz efficacy not compromised when switched to lower dose

In the management of virologically suppressed patients living with HIV, efavirenz 400 mg has noninferior efficacy and favourable safety as compared with the 600 mg-based regimen, according to a study from China.

The study included 209 patients (median age 33.6 years, 98.1 percent men, median body mass index 22.72 kg/m²) with virological suppression whose treatment regimen consisted of tenofovir, lamivudine, and efavirenz 600 mg. These patients were randomized to continue original regimen or switch to two-tablet efavirenz 200 mg.

All patients completed self-reported adherence questionnaires, including the 12-Item Short-Form Health Survey (SF-12), Hospital Anxiety and Depression Scale (HADS), and Pittsburgh Sleep Quality Index (PSQI) at baseline and week 48. The primary outcome was the difference in proportions of patients with plasma HIV-RNA ≥50 copies/mL at week 48 with noninferiority margin of 4 percent.

Of the patients, 299 (71.2 percent) reported previous unprotected sex with men. The assay did not detect HIV-RNA in 91.0 percent of the population. Median time on antiretroviral therapy was 3.4 years, while median CD4+ T cell count was 558 cells/μl.

At week 48, virological failure occurred in 11 patients in the efavirenz 400-mg group and in 18 in the 600-mg group (5.3 percent vs 8.5 percent, respectively). The difference was –3.3 percent (95 percent confidence interval [CI], –8.1 to 1.6), indicating that the 400-mg regimen was noninferior to the 600-mg regimen.

There were no significant changes in adherence, quality of life, and neuropsychologic condition documented. On the other hand, switching to the 400-mg efavirenz regimen led to a greater improvement of safety in terms of liver enzyme and blood lipid.