HIV PEP with emtricitabine/tenofovir/rilpivirine has excellent completion and adherence rates

Daily post-exposure prophylaxis (PEP) with single tablet emtricitabine/tenofovir/rilpivirine (Complera, Eviplera) has excellent completion rates and good side-effect and safety profiles, Australian investigators report in the online edition of Clinical Infectious Diseases.

The open-label, non-randomised study involved 100 men who have sex with men (MSM) requiring PEP after possible sexual exposure to HIV. Treatment lasted 28 days and was completed by 92% of participants. Side-effects were mild, the most common being nausea and tiredness. There were no serious adverse events.

Prompt PEP, after possible sexual or occupational exposure to HIV, can reduce the risk of infection. Guidelines recommend triple-drug therapy, ideally commenced within 72 hours of exposure.

Glossary

post-exposure prophylaxis (PEP)

A month-long course of antiretroviral medicines taken after exposure or possible exposure to HIV, to reduce the risk of acquiring HIV.

serum

Clear, non-cellular portion of the blood, containing antibodies and other proteins and chemicals.

 

nausea

The feeling that one is about to vomit.

plasma

The fluid portion of the blood.

open-label

A clinical trial where both the researcher and participants know who is taking the experimental treatment. 

Failure of PEP has been linked to poor treatment adherence or the premature discontinuation of treatment. A recent analysis of 97 PEP studies found that only 57% of patients completed their four-week course of treatment.

The combination pill emtricitabine/tenofovir/rilpivirine provides well tolerated and easy-to-take once-daily HIV therapy. Though it must be taken with food, investigators from Australia hypothesised that the combination pill would provide convenient and safe PEP.

They therefore designed a study to describe completion rates, adherence and safety of emtricitabine/tenofovir/rilpivirine as a 28-day PEP regimen.

Recruitment took place at two sexual health and two hospital emergency departments between late 2012 and mid 2014. HIV-negative MSM requiring PEP because of possible HIV exposure within the previous 72 hours were eligible for recruitment. Patients presented within a mean of 30 hours of risky anal sex and PEP was commenced, an average of two hours after presentation.

The completion rate was 92%. In regards to the non-completers, six patients were lost to follow-up, one individual withdrew because of side-effects and a single patient withdrew because of the inconvenience of study visits.

Adherence rates were extremely high among the patients who completed their therapy – 99% by both self-report and pill count. Plasma drug levels were monitored in 50 patients. All had therapeutic levels of emtricitabine and 88% had tenofovir levels above 40ng/ml.

Most patients (88%) reported one or more side-effects. But generally these were mild and the most common were fatigue (34%) and nausea (23%). Only four patients experienced a moderately severe side-effect possibly related to a study drug.

The majority of patients (n = 56) experienced a laboratory abnormality, but once again these were generally mild. A single patient developed pancreatitis within a week of completing PEP. This resolved within 21 days without the need for hospitalisation.

Therapy with tenofovir has been associated with kidney function. Serum creatitine rose modestly between baseline and week four of treatment. However, there were no cases of serious toxicities and mean serum phosphate levels did not change significantly.

No participant seroconverted for HIV.

The investigators concluded that once-daily PEP with emtricitabine/tenofovir/rilpivirine was well tolerated, with high levels of adherence and completion.

References

Foster R et al. Single-tablet emtricitabine-rilpivirine-tenofovir as HIV post-exposure prophylaxis in men who have sex with men. Clin Infect Dis, online edition, 2015.