Doravirine-lamivudine-tenofovir disoproxil well-tolerated as HIV postexposure prophylaxis

Among people with potential nonoccupational exposure to HIV, a single-tablet once-daily regimen (STR) of doravirine-lamivudine-tenofovir disoproxil is a well-tolerated postexposure prophylaxis (PEP) option, reports a study presented at the recently concluded 2022 HIV Glasgow Conference.

The prospective, open-label, single-arm study included 399 individuals (median age 30 years, 91 percent men) who had presented to the emergency department for potential sexual exposure to HIV. All were deemed eligible by responders for doravirine-lamivudine-tenofovir disoproxil treatment. Patients were followed up 10, 60, and 120 days after PEP initiation.

The primary endpoint was noncompletion of PEP, assessed after 28 days. Twenty-six percent (n=103) of participants failed to finish the 28-day doravirine-lamivudine-tenofovir disoproxil course, most of which were attributed to loss to follow-up (n=92; 89 percent). [HIV Glasgow 2022, abstract P011]

Other common reasons for dropout included intolerance (n=9; 9 percent) and withdrawal of consent (n=2; 2 percent).

Multivariate regression analysis revealed that older participants were 5-percent less likely to drop out of the PEP regimen (95 percent confidence interval, 0.92–0.98; p=0.006).

Aside from dropout, PEP adherence was also assessed at day 10 and week 4 using pill counts and a self-reported questionnaire. Data from 351 and 289 participants were available at each time point, respectively, of whom 96 percent and 99 percent were found to be adherent to the regimen.

The major mode of potential exposure was homosexual intercourse, reported in more than 80 percent of participants. Eighty-four percent (n=331) identified themselves as homosexual, while 13 percent (n=53) identified as heterosexual. Eleven participants said they were transexual. Attending physicians deemed 97 percent of the individuals to be at high risk of HIV infection.

Recreational drug use was common, documented in 30 percent. The most common substances were cannabis, cocaine, methamphetamine, and nitrites. A small minority of participants also had erectile dysfunction.

At baseline, 32 percent of participants had had prior episodes of sexually transmissible infections. Among these, the most common was gonorrhoea, followed by Treponema pallidum infection and chlamydia. Cases of human papillomavirus and herpes simplex virus infections were also reported but were rarer.

Aside from regimen acceptability, the current study also assessed the safety and tolerability of PEP using doravirine-lamivudine-tenofovir disoproxil.

Adverse events arose in 70 patients, yielding an incidence rate of 18 percent. Gastrointestinal toxicities were the most common, accounting for 51 percent of all side effects. This was followed by neurological toxicities at 30 percent. Systemic, dermatologic, genitourinary, and infectious adverse events were also documented.

Of note, no cases of HIV transmission were reported during the study.

Most of the side effects were mild in severity and resolved without needing external intervention (83 percent; n=82). Meanwhile, 14 percent of episodes were moderate, while 3 percent were severe.