TAMPA – Pre-exposure prophylaxis (PrEP) has shown to be effective in many clinical and real-world studies, but concerns remain, according to research presented at the annual meeting of the Association of Nurses in AIDS Care (ANAC).
Only about 20% of people who could benefit from PrEP use the preventative medication, for example. Another concern is adherence, as regular use generally drops off over time, rarely lasting more than a few months for most people.
Furthermore, most studies to date evaluated safety and effectiveness of PrEP options among men who have sex with men. Now the focus is increasing on other populations, including women at risk of HIV exposure.
Researchers working on new forms and formulations of PrEP are looking for ways to address those challenges.
said Craig W. Hendrix, MD, professor and director of the Division of Clinical Pharmacology at Johns Hopkins University School of Medicine, Baltimore.
“What I hear a lot of folks say [is] there are two or three options for PrEP, so why do we need more? We need choices that fit into a broader range of lifestyles,” Dr. Hendrix said.
For example, a medically fortified douche containing PrEP might be more likely to be used by people who use a douche before or after sex on a regular basis. This is called a “behaviorally congruent” strategy, Dr. Hendrix said.
In addition to a medical douche, formulations designed to continuously deliver PrEP, such as a subdermal implant, are in the works as well.
Another option for women, the dapivirine vaginal ring, is available internationally but not in the United States. “It was withdrawn from [Food and Drug Administration] consideration by the sponsor. I think it’s a huge loss not to have that,” Dr. Hendrix said.
During development, “frequent expulsions forced reformulation to a less stiff ring,” Dr. Hendrix said. “I don’t imagine that’s terrific, but it shows how important it is to have something that fits the anatomy and the lifestyle.”
“Currently, we have in the U.S. three licensed, really terrific options for PrEP, and they’re all for men that have sex with men and transgender women,” Dr. Hendrix said.
Three current options
The three current PrEP regimens in the United States often go by their abbreviations: F/TDF, F/TAF, and CAB-IM.
- F/TDF is emtricitabine (F) 200 mg in combination with tenofovir disoproxil fumarate (TDF) 300 mg (Truvada, Gilead or generics)
- F/TAF is emtricitabine (F) 200 mg in combination with tenofovir alafenamide (TAF) 25 mg (Descovy, Gilead)
- CAB-IM is cabotegravir (CAB) 600 mg injection (Apretude, GlaxoSmithKline)
There is an important distinction: Daily oral PrEP with F/TDF is recommended to prevent HIV infection among all people at risk through sex or injection drug use. Daily oral PrEP with F/TAF is recommended to prevent HIV infection among people at risk through sex, excluding people at risk through receptive vaginal sex, the CDC notes.
The cost-effectiveness of the injection remains a potential issue, Dr. Hendrix said. On the other hand, “cost-effectiveness goes out the window if there is no adherence.”