Injection every 2 months could stop HIV transmission, study shows

Every year almost 38,000 Americans are diagnosed with HIV. In 2012, the Food and Drug Administration approved groundbreaking medication known as PrEP, or preexposure prophylaxis, that if taken daily is up to 99% effective in lowering the risk of sexually transmitting HIV.

Now, new research shows that an injection given every two months -- rather than a pill you take every day -- can be just as effective. That injection, while not yet FDA-approved, would offer a new option for people trying to protect themselves from HIV.

"I think a lot people don't want to take the pill because it interferes with their daily activities or because they don't want pill bottles laying around the house for everyone to see," says Brandon Jackson, a participant in a study called HPTN 083, that offered the every two month injection.

If not taken daily, the pill's effectiveness at preventing HIV decreases significantly.

Jackson notes that people have many reasons for not wanting to take a daily pill including remembering to take the pill, the logistics of getting refills and even the possible stigma associated with having an HIV medication in your medicine cabinet.

Many of the people trying to protect themselves from HIV are men who have sex with men, and it's possible the presence of an anti-HIV pill bottle in their medicine cabinet might raise questions the person they are prescribed to may not want to answer. It's also not intuitive for some people who feel otherwise healthy to take a pill every day, whereas getting a shot every 2 months can be accomplished during a scheduled doctor visit.

Jackson participated in a study called HPTN 083, which compared a medication called cabotegravir, given as a shot every eight weeks, against an already-approved daily HIV prevention pill called Truvada.

The study found that, overall, the injection was as effective, if not more effective, than the pill in preventing HIV infections.

"The injection is so much easier," says Jackson. "I probably wouldn't take a daily pill. I am really a fan of the shots; it's difficult to be 100% adherent to the pills and easy to miss a dosage. The shots are much more convenient."

"We know PrEP works. Compliance is the real kicker," said Dr. Todd Ellerin, director of infectious diseases at South Shore Health and an ABC News Contributor. "The crux of this study is that it takes something that works and makes it better because of compliance," said Dr. Ellerin, who is compensated for making speeches to other doctors for the companies ViiV and Gilead that make the drugs.

So as the U.S. death toll from the COVID-19 pandemic now stands at more than 107,000 people and a race is on to find a safe and effective vaccine against the virus that causes COVID-19 -- doctors who work on HIV prevention are especially heartened by the study results.

"Everything overshadowed by COVID and corona -- to get this news during tough times, is thrilling, really," said Dr. Colleen Kelley, Associate Professor of Infectious Diseases at Emory University School of Medicine and one of the study's researchers. "It puts a boost in our sails." she stated.

The HPTN 083 study enrolled 4,570 men in seven different countries including the United States, South Africa, Vietnam and Argentina.

Participants were randomly assigned to one of two groups, with one group receiving an anti-HIV medication injection, cabotegravir, every eight weeks and an inactive form of pills. The other group received an inactive form of the injection and the anti-HIV pill called Truvada.

Both medications work by blocking the HIV virus from multiplying in the body. During the study, 50 participants became infected with HIV. Of those 50 newly infected participants, 12 were receiving the cabotegravir injection and 38 were taking the Truvada pill.

Based on these results, the NIH stopped the 'blinded' part of the study because the results clearly showed that cabotegravir works just as well -- if not better than -- the existing Truvada pill. The positive results were announced to the public earlier than expected, and the people who volunteered for the study told which type of medication they had received.

"When the NIH stops a study early it's a big deal," said Ellerin. "They are trying to send a signal about the study."

Moreover, Kelley notes the results were also compelling because all of the participants were men who have sex with men or transgender women who have sex with men.

"Look, historically it has not been the case to include this group, they are often underrepresented in clinical trials," she said noting that men from non-white racial groups have an elevated risk of contracting HIV/AIDS.

According to statistics from the federal government African American and Latino gay and bisexual men represent the highest proportions of new HIV/AIDS infections in the United States.

Importantly, the study participants were diverse and represented populations that are most affected by HIV. Two-thirds of the study participants were under 30, about 12% were transgender women, and half identified as Black or African American.

Also, while waiting for FDA approval, HIV/AIDS and public health specialists remain optimistic, but note more information is needed with regards to cost.

"This is a very exciting finding with regards to HIV prevention; choice is always better" states Dr. David Holtgrave, Dean of the School of Public Health at University of Albany. "What wasn't addressed in the trial was the cost effectiveness of using an injectable instead of a pill -- we don't know the cost per injection."

Cabotegravir has already been studied extensively in clinical trials. In fact, the injectable drug -- when combined with a second medication called rilpivirine -- is already approved in Canada as a treatment for people who are already infected with HIV. ViiV, the company that makes cabotegravir, says it expects cabotegravir and rilpivirine to be approved as an HIV treatment by 2021 in the United States.

When it comes to HIV prevention, ViiV and the NIH are still studying cabotegravir alone, without the second add-on drug. It's not clear exactly when this stand-alone HIV prevention medication will be available in the United States, but researchers are continuing to study its effectiveness in different groups of people, including heterosexual women.

Pending FDA approval, it remains unclear how much either injection will cost. Currently, Truvada and other HIV daily prevention pills are covered by most insurance plans and Medicaid, although many require a complex pre-authorization process and have associated out of pocket costs that can make the medication unaffordable even for the insured.

Monica Saxena, M.D., J.D., is a contributing member of the ABC News Medical Unit.