People with HIV who switch from taking Atripla (efavirenz/tenofovir disoproxil fumarate/emtricitabine) daily to taking the single-tablet antiretroviral (ARV) regimen every other day still maintained a high rate of viral suppression at one year, aidsmap reports.

Publishing their findings in the journal AIDS, researchers enrolled into a study 197 Italians who were taking Atripla daily to treat HIV and had had a fully suppressed viral load (below 40) for at least six months. Exclusion criteria for the study included having a history of virologic failure, resistance to any of the three ARVs included in Atripla, and pregnancy.

Ninety percent of the cohort was male and 68 percent contracted HIV through sex with another man. The median age was 43.2 years old. The median CD4 count was 677. Cohort members had been taking Atripla for a median of 38.3 months and had been living with HIV for a median of 6.8 years.

The participants were randomized evenly to stay on daily Atripla or switch to every-other-day dosing of the regimen. After 48 weeks, 97 percent of those in the daily-dosing group and 94 percent of the group assigned to take Atripla every second day had a fully suppressed viral load. The difference between these two rates was not statistically significant, meaning it could have been driven by chance.

The median CD4 count increase by week 48 was 29.4 CD4s among those in the daily dosing group and 61 CD4s in the every-other-day group.

The median baseline concentration in the blood of the efavirenz component of Atripla was 2,421 nanograms per milliliter among the study members as a whole. The median change in efavirenz concentration by week 48 was a 6.5 ng/ml decline in the daily dosing group and a 1,124 ng/ml decline in the alternate-day dosing group.

Regardless of their study group, the participants exhibited comparable rates of cholesterol or triglyceride changes and neuropsychological symptoms, such as sleep quality, anxiety and dizziness. Efavirenz’s association with such neuropsychiatric symptoms has contributed to the drug’s loss of status as a recommended component of first-line treatment in the United States.

At week 48, 86 percent of the every-other-day dosing group reported adhering well to their drug regimen, compared with 73 percent of the daily-dosing group.

To read the aidsmap article, click here.

To read the study abstract, click here.