Study: Preventive Ring Does Not Cause Drug Resistance in HIV

Amanda Balbi

A monthly vaginal ring containing the antiretroviral non-nucleoside reverse transcriptase inhibitor (NNRTI) drug dapivirine reduces the risk of human immunodeficiency virus (HIV) infection by 27%, according to the latest results of the ASPIRE trial.

ASPIRE—A Study to Prevent Infection with a Ring for Extended Use, or MTN-020—is a phase III trial that examined the safety and efficacy of the dapivirine vaginal ring in protecting against HIV.
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The study enrolled HIV-free women aged 18 to 45 years at 15 trial sites in Malawi, Uganda, South Africa, and Zimbabwe.

The women were randomly assigned to receive a dapivirine ring or a placebo ring. Blood samples were drawn to test for HIV and HIV mutations that may lead to NNRTI resistance.

Of the 2629 participants, 168 acquired HIV during the trial period (97 in the placebo arm and 71 in the active arm).

Results of subsequent analyses pointed to adherence as a major factor in outcomes, but, the researchers noted, there was little difference in the rate of resistance to NNRTIs between the arms of the study and no indication of dapivirine-specific resistance.

After collecting plasma for genotyping, the researchers found that 18 of the participants had various NNRTI-resistance mutations, but the frequency of these mutations did not differ significantly, suggesting that resistance was acquired, and not caused by the drug.

—Amanda Balbi

Reference:

van der Straten A, Cheng H, Brown ER, et al; MTN-020/ASPIRE Study Team. Are ring worries affecting use? Findings from the MTN-020/ASPIRE phase III dapivirine ring trial. Paper presented at: HIV Research for Prevention; October 17-21, 2016; Chicago, IL. http://www.professionalabstracts.com/hivr4p2016/iPlanner/#/grid. Accessed October 20, 2016.