Will Cabotegravir be a Game-changer in HIV Prevention?

A staggering 36.7 million people worldwide are living with HIV, a virus that targets CD4 cells in the body that help the immune system fight off a number of harmful infections. Once an individual acquires HIV, the individual has it for life, which is why preventive measures are so crucial, particularly for high risk populations. However, an announcement made by the National Institute of Allergy and Infectious Diseases (NIAID) at the National Institutes of Health (NIH) may bring a game-changer in the fight against HIV.

The first large-scale Phase III clinical trial of cabotegravir, an injectable drug designed to deliver effective HIV prevention, was launched on Tuesday, according to a press release. With this study, researchers hope to find out if long-acting cabotegravir—to be injected once every 8 weeks—is as effective as Truvada in preventing HIV in men who have sex with men (MSM) and transgender women who have sex with men.

Currently, Truvada—comprised of the drugs emtricitabine and tenofovir disoproxil fumarate—is “the only licensed PrEP regimen” to which individuals are required to receive each day in the form of an oral tablet. With this study, researchers hope to provide another preventive option for those at risk that may be easier to adhere to than Truvada.

In the press release, Anthony S. Fauci, MD, director of NIAID, said, “We urgently need more HIV prevention tools that fit easily into people’s lives. Although daily oral Truvada clearly works for HIV prevention, taking a daily pill while feeling healthy can be difficult for some people. If proven effective, injectable cabotegravir has the potential to become an acceptable, discreet and convenient alternative for HIV prevention.”

The study, dubbed HPTN 083, is the result of a collaborative effort between: NIAID, ViiV Healthcare, Gilead Sciences, Inc., and the HIV Prevention Trials Network (HPTN). HPTN 083 will enroll 4,500 high-risk MSM and transgender women who have sex with men, aged 18 or older. The participants will come from 45 sites in Argentina, Brazil, India, Peru, South Africa, Thailand, the United States, and Vietnam. Researchers estimate that the results of the study will be available in 2021.

After participants are assigned at random to either the cabotegravir group or the Truvada group, they will participate in the study for the duration of four and a half years. For the first five weeks following enrollment, the participants will be administered two tablets—either of cabotegravir, Truvada, or placebo—to be taken daily. On the sixth week, “participants in the cabotegravir group will receive injections of cabotegravir and placebo tablets to be taken orally daily, while participants in the Truvada group will receive placebo injections with Truvada tablets to be taken orally daily.” According to the press release, participants will receive the first two injections 4 weeks apart and then, after that, participants will receive their injections once every 8 weeks for the rest of the study. When participants have received all of the injections, they will have the opportunity to receive 48 weeks of pre-exposure prohylaxis along with Truvada (to be taken daily).

Furthermore, all study participants will be provided with counseling on both prevention and adherence to the oral pill and will be supplied with condoms and lubricant. If participants acquire a sexually transmitted disease (STD) during the study, they will be referred to local healthcare providers for appropriate treatment and will stop receiving the study products.

HIV remains a public health concern around the world and researchers hope that this drug might be a more convenient way to prevent infection and increase adherence. There are a number of reasons why adhering to medical treatment for HIV can be difficult: individuals may have trouble swallowing pills; a busy schedule may prevent the individual from taking the medication on time; or they might not want to call attention to the fact that they have the virus. With an 8-week, injectable dosage, researchers feel that it will be easier for individuals to adhere to the treatment in a much more discreet manner.

HPTN 083 Protocol Chair Raphael J. Landovitz, MD, MSc, said, “The annual number of new HIV infections among young men who have sex with men and transgender women who have sex with men, has been on the rise despite nearly flat HIV incidence among adults worldwide. It is essential to develop multiple effective HIV prevention modalities so the most vulnerable populations have a choice of preventive options. We hope injectable cabotegravir will become one such modality.”

The researchers noted that this is not the only study that will test injectable cabotegravir; it will also be tested for effective HIV prevention in women in a study called HPTN 084. The study will begin next year and focus on younger women in sub-Saharan Africa, a place that has been heavily hit with the virus.