The study began enrollment in August, 2018 and had its last enrollment in March, 2020. Of 52 enrollees, the median age was 37.2 years (range: 21–71); 76.9% identified as white, 11.5% mixed race, 5.8% Black, and 5.8% Asian or Pacific Islander; 9.6% identified as Latino/a (Table 1). Most identified as cisgender men (94.2%), but sexual orientation varied, with 67.3% of the sample identifying as gay/homosexual, 11.5% bisexual, and 7.7% heterosexual. One of the male participants identified as "heteroflexible" and another as "pansexual." Two heterosexual cisgender women enrolled, and one transgender man enrolled, who identified as "queer." Most participants (70.8%) completed college. The behaviors that led to PEP initiation included: condomless receptive (51.9%) or insertive (42.3%) anal sex, and condomless receptive (5.8%) or insertive (5.8%) vaginal sex; over half the sample (57.7%) also reported oral sex. More than half (55.8%) described more than one potential exposure to HIV. Only 15.4% reported that their exposure was with a sexual partner known to be HIV-positive.
The most common side effects that PEP patients experienced when using BIC/FTCTAF included: nausea or vomiting (15.4%), fatigue (9.6%), and diarrhea or loose stools (7.7%) (Table 2). Other adverse events that were reported by one participant each that could have been related to the drug regimen included: headache, myalgias/arthralgias, rectal irritation, flatulence, forearm rash, dry mouth, nightmares, dysuria, and gastroenteritis. Creatinine clearance decreases were detected in 7 (13.5%) of the samples, with 4 of them being grade 2. Grade 1 elevated transaminases were seen in 2 (3.8%) participants. Each of these laboratory abnormalities were asymptomatic and resolved after the PEP regimen was completed on day 28. Adverse events believed not to be related to the regimen included: upper respiratory infections in 4 (7.7%) and viral syndrome in 2 (3.8%) of the participants. Fourth finger laceration, rectal discharge, vaginal discharge, acute sinusitis, dysuria, and flank pain were each reported by one participant. Some of the symptoms may have been related to diagnoses of urogenital and oropharyngeal C. trachomatis infection, and rectal N. gonorrhoeae infection in one participant each. Most symptoms were mild and self-limited, with only one, grade 2 fatigue, was associated with early drug regimen discontinuation.
BIC/FTC/TAF was less likely to be associated with any symptom compared with historical regimens containing zidovudine and a protease inhibitor (Table 2), and was less likely to cause diarrhea/loose stools or headache compared with any of the other regimens studied at the center. BIC/FTC/TAF was less likely to be associated with fatigue compared with TDF/FTC plus elvitegravir and cobicistat, and less likely to be associated with dizziness or lightheadedness than TDF/FTC plus raltegravir. Although there was not a statistically significant difference in the prevalence of nausea or vomiting in the BIC/TAF/FTC PEP regimen compared with the others, the rate (15.4%) was the lowest of the 4 regimens.
Most participants (90.4%) completed the BIC/TAF/FTC regimen without modification as determined by per pill count and self-report, which was significantly better than the other regimens, with completion rates ranging from 38.8% to 71.0% (Table 3). None of the participants tested at 4 weeks and interviewed at 3 months became HIV-positive.
J Acquir Immune Defic Syndr. 2022;90(1):27-32. © 2022 Lippincott Williams & Wilkins