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Prevention of HIV infection in cisgender men and transgender women who have sex with men is an important step toward realizing the promise of long-acting antiretrovirals; work remains to address issues of implementation and access

Jeremiah Johnson:

New York City, May 19, 2020 – Treatment Action Group (TAG) welcomes the news that long-acting injectable cabotegravir (CAB LA, from ViiV Healthcare) demonstrated a high level of efficacy for preventing HIV infection in cisgender men and transgender women who have sex with men in the HIV Prevention Trials Network (HPTN) 083 trial.[1]

Among the 4,570 participants randomized to receive either injections of CAB LA every two months or daily Truvada (emitricitabine and tenofovir disoproxil fumarate), the incidence of HIV acquisition over the two years of the study was 0.38% (12 infections) in the CAB LA arm versus 1.21% (38 infections) in the Truvada arm. The results met the trial protocol’s pre-specified statistical criteria for non-inferiority.

“TAG commends the commitment of the trial investigators, sponsors, and participants,” said Jeremiah Johnson, TAG’s HIV Project Director. “We look forward to the publication of the full results, including a more detailed assessment of the timing of the 12 infections that occurred in the CAB LA arm.”

The findings were announced sooner than expected. Concerns about the COVID-19 pandemic led investigators to request that the Data and Safety Monitoring Board stop the trial early if the primary endpoint of non-inferiority was achieved. Originally, the interim monitoring plan called for stopping only if statistical criteria for establishing the superiority of CAB LA were met.[2] ViiV Healthcare’s claim that CAB LA was “69% more effective” is misleading, since superiority has not yet been demonstrated.[3]

ViiV Healthcare’s press release about the HPTN 083 trial contains only limited safety data, describing higher rates of injection site reactions among CAB LA recipients but relatively few discontinuations due to toxicity (2% of participants in the CAB LA arm).3

HPTN 083 enrolled a diverse cohort across seven countries. Overall, 12% of participants identified as transgender women. Two-thirds of participants were under 30 years of age. In the U.S., half of the participants identified as Black or African American.

“Long-acting antiretrovirals (and possibly also broadly neutralizing antibodies) have a clear potential to further revolutionize HIV prevention and treatment,” noted Richard Jefferys, TAG’s Basic Science, Vaccines & Cure Project Director. “But there remain important outstanding issues to address in order for that potential to be realized.”

Important next steps include:

  • Learning whether CAB LA PrEP is efficacious in cisgender women: Forthcoming data from the HPTN 084 trial evaluating PrEP in cisgender women will be a vital next step toward equity for affected populations;
  • Developing evidence-based best practices for implementation: Logistical issues attend administration of CAB LA, including oral lead-in dosing, bimonthly injections requiring clinic visits, and oral dosing to cover a prolonged decline in drug levels when injections are stopped;
  • Setting an affordable price for CAB LA: The price that ViiV Healthcare intends to charge for CAB LA is not yet known. Ensuring affordable access for all who stand to benefit will be essential, and is especially warranted as public funding supports research into CAB LA for prevention;
  • Clarifying any regulatory issues: In December 2019, the U.S. Food and Drug Administration delayed approving ViiV’s marketing application for Cabenuva because of concerns related to manufacturing.[4] Cabenuva is a once-monthly long-acting injectable treatment for HIV that also contains cabotegravir (along with another antiretroviral, rilpivirine);
  • Determining implications for future prevention trials: The advent of CAB LA PrEP will affect future efficacy trials of other biomedical prevention interventions. Ethics require that trial participants have access to the best available prevention methods, so the question of how to approach CAB LA PrEP provision and usage will need to be addressed.

While work remains, the arrival of intermittent options for prevention and treatment offers great promise. TAG hopes that the HPTN 083 results mark another leap forward toward ending the HIV epidemic.

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About TAG: Treatment Action Group (TAG) is an independent, activist and community-based research and policy think tank fighting for better treatment, prevention, a vaccine, and a cure for HIV, tuberculosis, and hepatitis C virus. TAG works to ensure that all people with HIV, TB, and HCV receive lifesaving treatment, care, and information. We are science-based treatment activists working to expand and accelerate vital research and effective community engagement with research and policy institutions.

[1] HIV Prevention Trials Network (News Release). Long-acting injectable cabotegravir is highly effective for the prevention of HIV infection in cisgender men and transgender women who have sex with men. May 18, 2020.

[2] Cohen J. Long-acting injectable drug prevents HIV infections. Science. May 18, 2020.

[3] ViiV Healthcare (News Release). Global HIV prevention study to stop early after ViiV Healthcare’s long-acting injectable formulation of cabotegravir dosed every two months shows higher efficacy than daily oral PrEP. May 18, 2020.

[4] Collins S. FDA decision on long-acting cabotegravir/rilpivirine (Cabenuva) injections delayed due to scale-up manufacturing problems. HIV i-Base. January 29, 2020.

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