NIH Tests New PrEP Delivery Method

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The National Institutes of Health (NIH) has sponsored a clinical trial to study the effectiveness and safety of a rectal microbicide containing the antiretroviral drug tenofovir as a pre-exposure prophylaxis method (PrEP). In the trial, this method of delivery is being compared with oral PrEP, according to a recent news release.

The study, which began on Oct. 29, plans to enroll about 150 participants across eight sites in the United States. Only one of the sites is currently enrolling, according to the trial website. Participants must be assigned male at birth and have regular experience using a rectal douche before sex. The study is expected to last until January 2026. Self-reported data on ease of use will also be collected.

After enrollment, participants will be put into two groups:

Group A will begin with the rectal douche, which contains 660 mg of tenofovir for the first eight weeks, and then following a two to four-week washout period, switch to the oral PrEP pills containing a combination of emtricitabine/tenofovir disoproxil fumarate (F/TDF) 200 mg/300 mg sequence.

Group B will begin with the on-demand oral F/TDF 200 mg/300 mg sequence for the next eight weeks and then switch to the rectal TFV 660 mg douche.

Participants are required to use the douche at least weekly, prior to rectal intercourse.

Although HIV rates are on the decline in the United States, 67% of diagnoses from 2018-2022 were among men who have sex with men, signaling a need for improved PrEP options, the news release said.

On-demand PrEP is an increasingly popular form of PrEP both in the United States and globally due to convenience. Oral PrEP (F/TDF) must be taken every day to reach maximum effectiveness and takes about seven days of daily use to do so. Another option known as "2-1-1" dosing of oral PrEP, requires patients to take two pills 2-24 hours before sex, one pill 24 hours after the first dose and one pill 48 hours after the first dose, according the Centers for Disease Control and Prevention (CDC).

Other forms of PrEP include an injection, administered every two months, and the dapivirine ring, which is a flexible silicone ring inserted into the vagina that continuously releases antiretroviral drug dapivirine.