Chemoprophylaxis With Oral Emtricitabine and Tenofovir Alafenamide Combination Protects Macaques From Rectal Simian/Human Immunodeficiency Virus Infection

Tenofovir alafenamide (TAF) is a novel prodrug of tenofovir that efficiently delivers tenofovir diphosphate to lymphoid cells following oral administration. We investigated whether the combination of TAF and emtricitabine (FTC) could prevent simian/human immunodeficiency virus (SHIV) infection in macaques to determine the potential use of TAF for pre-exposure prophylaxis (PrEP) to prevent human immunodeficiency virus infection. Macaques were exposed rectally to SHIV once per week for up to 19 weeks and received saline or FTC/TAF 24 hours before and 2 hours after each virus inoculation. All 6 controls were infected, while the 6 PrEP-treated animals were protected from infection. Our results support the clinical investigation of FTC/TAF for PrEP.