Pre-Exposure Prophylaxis for HIV Prevention: Safety Concerns

Abstract

Available evidence supports the efficacy of pre-exposure prophylaxis (PrEP) in decreasing the incidence of human immunodeficiency virus (HIV) infection among high-risk individuals, especially when used in combination with other behavioural preventive methods. Safety concerns about PrEP present challenges in the implementation and use of PrEP. The aim of this review is to discuss safety concerns observed in completed clinical trials on the use of PrEP. We performed a literature search on PrEP in PubMed, global advocacy for HIV prevention (Aids Vaccine Advocacy Coalition) database, clinical trials registry “http://www.clinicaltrials.gov” and scholar.google, using combination search terms ‘pre-exposure prophylaxis’, ‘safety concerns in the use of pre-exposure prophylaxis’, ‘truvada use as PrEP’, ‘guidelines for PrEP use’, ‘HIV pre-exposure prophylaxis’ and ‘tenofovir’ to identify clinical trials and literature on PrEP. We present findings associated with safety issues on the use of PrEP based on a review of 11 clinical trials on PrEP with results on safety and efficacy as at April 2016. We also reviewed findings from routine real-life practice reports. The pharmacological intervention for PrEP was tenofovir disoproxil fumarate/emtricitabine in a combined form as Truvada® or tenofovir as a single entity. Both products are efficacious for PrEP and seem to have a good safety profile. Regular monitoring is recommended to prevent long-term toxic effects. The main adverse effects observed with PrEP are gastrointestinal related; basically mild to moderate nausea, vomiting and diarrhea. Other adverse drug effects worth monitoring are liver enzymes, renal function and bone mineral density. PrEP as an intervention to reduce HIV transmission appears to have a safe benefit-risk profile in clinical trials. It is recommended for widespread use but adherence monitoring and real-world safety surveillance are critical in the post-marketing phase to ensure that the benefits observed in clinical trials are maintained in real-world use.