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Topical application of antiretroviral drug combination prevents transmission of (S)HIV

Researchers are edging ever closer to discovering the perfect combination of drugs and drug delivery system that will stop the sexual transmission of HIV. Findings published last week in the journal PLOS ONE confirm that researchers from the Oak Crest Institute of Science, located in Monrovia, CA, have demonstrated for the first time that two powerful antiretroviral (AVR) drugs can provide complete protection against HIV when delivered topically by a sustained release intravaginal ring (IVR) device.

Results of the study, Topical Delivery of Tenofovir Disoproxil Fumarate and Emtricitabine from Pod-Intravaginal Rings Protect Macaques from Multiple SHIV Exposures, confirm that the combination of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) delivered at independently controlled rates via the pod-IVR were successful at preventing SHIV162p3 infection in a rigorous, repeat low-dose vaginal exposure model using normally cycling female pigtailed macaques.

“We are extremely pleased with the results of this study,” says Dr. Marc M. Baum, president and senior faculty at Oak Crest. “The observed protection in macaques indicates the significant potential for the TDF-FTC drug combination delivered via the pod-IVR to successfully prevent sexual HIV infection in humans.”

Throughout the six-month study, conducted at the Centers for Disease Control and Prevention (CDC) in Atlanta, GA, six macaques received pod-IVRs containing 65 mg of TDF and 68 mg of FTC every two weeks. One week after the first pod-IVR insertion, the macaques received the first of 16 vaginal exposures to 50 TCID50 of SHIV162p3, a chimeric SIV/HIV virus that infects macaques. The rings were exchanged every two weeks (three days prior to the next weekly virus exposure) corresponding to a total of eight ring changes during the 18-week period, with the final ring removal at week 18. Complete protection was achieved in all (six of six) animals with TDF-FTC pod-IVRs compared to 0 of 9 control animals without pod-IVRs over four months of weekly virus exposures that spanned several menstrual cycles.

Image of intravaginal ring (IVR) device
Researchers are edging ever closer to discovering the perfect combination of drugs and drug delivery system that will stop the sexual transmission of HIV
Image Credit: Dr. Marc M. Baum