DURHAM, N.C. - Researchers from the HIV Prevention Trials Network (HPTN) announced today that the HPTN 083 clinical trial showed that a pre-exposure prophylaxis (PrEP) regimen containing long-acting cabotegravir (CAB LA) injected once every 8 weeks was superior to daily oral tenofovir/emtricitabine (TDF/FTC) for HIV prevention among cisgender men and transgender women who have sex with men. The results were reported at the 23rd International AIDS Conference (AIDS 2020: Virtual). HPTN 083 is a randomized, controlled, double-blind study comparing the safety and efficacy of a regimen including CAB LA to daily TDF/FTC at 43 sites around the world.
An independent Data and Safety Monitoring Board (DSMB) that reviewed interim study data in May 2020 found that the PrEP regimen including CAB LA injected once every 8 weeks safely and effectively prevented HIV acquisition in the study population. Consequently, the DSMB recommended stopping the blinded comparison, offering CAB to all study participants, and disseminating the results. The final analysis of these data demonstrates the superiority of CAB compared to TDF/FTC for PrEP in the HPTN 083 study population.
"The HPTN 083 results demonstrating the superiority of CAB to TDF/FTC have the potential to transform the landscape of HIV prevention for cisgender MSM and transgender women," said HPTN 083 protocol chair Dr. Raphael J. Landovitz. "We know that some people have difficulty with or prefer not to take pills, and an injectable product such as long-acting CAB could be a very important option for them. We want to thank the study participants and research staff, as this study would not have been possible without their dedication and commitment." Dr. Landovitz is a professor of medicine at the David Geffen School of Medicine at the University of California, Los Angeles (UCLA) and co-director of the UCLA Center for Clinical AIDS Research & Education (CARE).
Overall, HPTN 083 enrolled 4,570 cisgender men and transgender women who have sex with men at research sites in Argentina, Brazil, Peru, South Africa, Thailand, the U.S., and Vietnam. Two-thirds of study participants were under 30 years of age, and 12% were transgender women. Half of the participants in the United States identified as Black or African American.
A total of 52 HIV infections occurred during follow-up, with 13 infections in the CAB arm (incidence rate 0.41%) and 39 infections in the TDF/FTC arm (incidence rate 1.22%). The hazard ratio in the CAB versus TDF/FTC arms was 0.34 (95% CI 0.18-0.62), corresponding to a 66% reduction in incident HIV infections in study participants given CAB compared to TDF/FTC. These results meet the statistical criteria for superiority of the regimen containing CAB compared to TDF/FTC in the HPTN 083 study population. The consistent adherence to TDF/FTC throughout the study and low incidence rate in both arms of the study clearly demonstrates both agents were effective at preventing HIV acquisition.
"Adding long-acting injectable CAB to the HIV prevention toolbox could go a long to lowering HIV incidence among cisgender men and transgender women who have sex with men worldwide and, eventually, toward ending the epidemic," said HPTN 083 protocol co-chair Dr. Beatriz Grinsztejn, director of the Instituto de Pesquisa Clinica Evandro Chagas HIV/AIDS Clinical Research Centre of the Oswaldo Cruz Foundation-Fiocruz in Rio de Janeiro.
"It is heartening that HPTN 083 showed that both the regimen containing CAB and oral TDF/FTC demonstrated high efficacy for prevention of HIV acquisition in the study, offering people options that best fit their lifestyle," said Dr. Myron Cohen, HPTN co-principal investigator and director of the Institute for Global Health at the University of North Carolina in Chapel Hill.
An ongoing study, HPTN 084, is comparing the safety and efficacy of CAB LA to oral TDF/FTC for PrEP among cisgender women in sub-Saharan Africa. This study began approximately a year after the launch of HPTN 083 and was also reviewed in May 2020 by the DSMB, which recommended that the study continue as planned.
"We look forward to the results from HPTN 084, a critically important sister study among women at risk for HIV in sub-Saharan Africa," said Dr. Wafaa El-Sadr, HPTN co-principal investigator, director of ICAP and professor of epidemiology and medicine at Columbia University in New York. "Offering various HIV prevention options to women is critically important for control of the global HIV epidemic."