A New PrEP Implant Could Work For A Whole Year

Research presented at the International AIDS Conference in Mexico City shows promising results for a new HIV prevention drug implant by the drug company Merck. According to data, the implant might be able to protect people against the virus for a whole year.

The implant contains the investigational drug islatravir, the first in a new class of drugs called nucleoside reverse transcriptase translocation inhibitors, which block movement of the enzyme responsible for cloning HIV's DNA so that it can infect new cells, as described by the New York Times. 

Similar to strategies used for birth control, this implant is a matchstick-sized plastic rod that will be inserted under the skin of the upper arm and slowly release tiny doses of islatravir.

The trial, conducted by the pharmaceutical company MSD, is the first trial of a PrEP implant in humans. Researchers gave 12 healthy adults an implant for 12 weeks, which contained either a 54mg or 62mg dose of islatravir. Meanwhile, a control group of four people were given placebo implants. (14 of the 16 total participants were men.) 

The results showed that the implant was tolerated well in the body, and a closer inspection of the drug concentration in their bodies led researchers to believe that the implant could possibly have worked for at least another eight months for the lower-dose implant, and at least a year for the higher-dose implant. 

While a long-form trial would be needed to conclude whether or not a year-long implant would work, it hasn't stopped experts from being excited about the potential. 

“If — and I’m emphasizing if — if it pans out in a larger trial that it delivers a level of drug that’s protective for a year, that would be a game-changer,” Dr. Anthony S. Fauci, director of the National Institute for Allergy and Infectious Disease and a leading expert on AIDS, said to theTimes. 

A PrEP implant would greatly impact the number of HIV diagnoses. As previously reported, the Centers for Disease Control and Prevention announced that PrEP among at-risk men increased 500 percent between 2014 to 2017. Those numbers are expected to rise following Gilead Sciences' new commitment to donate up to 2.4 million bottles of Truvada to the CDC by 2030 (which amounts to 200,000 per year).

Truvada is the only FDA-approved drug that can be prescribed as PrEP. It is a daily pill, which makes adherence all the more difficult for people with busy lives or those who simply don't have access.

Women in Africa are particularly desperate for prevention methods that are easier to use than daily Truvada. According to UNAIDS, over 6,000 young women under age 24 are infected every week, and 80 percent of infected teenagers in Africa are girls.

The ideas of a PrEP impant aren't exactly new. Two years ago, the Bill & Melinda Gates Foundation teamed up with Intarcia Therapeutics to invest upwards of $140 million with the intent of developing the first once or twice-yearly anti-HIV prophylactic to help prevent the spread of HIV in Sub-Saharan Africa and other countries.

While HIV diagnoses have decreased steadily in the last decade, numbers remained somewhat stable between 2012 and 2016. In 2017, 38,739 people received a positive diagnosis in the U.S.