Single dose topical inserts containing tenofovir alafenamide fumarate and elvitegravir provide pre- and post-exposure protection against vaginal SHIV infection in macaques.

BACKGROUND

Vaginal products for HIV prevention that can be used on-demand before or after sex may be a preferable option for women with low frequency or unplanned sexual activity or who prefer not to use daily or long-acting pre-exposure prophylaxis (PrEP). We performed dose ranging pharmacokinetics (PK) and efficacy studies of a vaginally applied insert containing tenofovir alafenamide fumarate (TAF) and elvitegravir (EVG) in macaques under PrEP or post-exposure prophylaxis (PEP) modalities.

METHODS

PK studies were performed in 3 groups of pigtailed macaques receiving inserts with different fixed-dose combinations of TAF and EVG (10/8, 20/16 and 40/24 mg). PrEP and PEP efficacy of a selected insert was investigated in a repeat exposure vaginal SHIV transmission model. Inserts were administered 4 h before (n = 6) or after (n = 6) repeated weekly SHIV exposures. Infection outcome was compared with macaques receiving placebo inserts (n = 12).

FINDINGS

Dose ranging studies showed rapid and sustained high drug concentrations in vaginal fluids and tissues across insert formulations with minimal dose proportionality. TAF/EVG (20/16 mg) inserts were selected for efficacy evaluation. Five of the 6 animals receiving these inserts 4 h before and 6/6 animals receiving inserts 4 h after SHIV exposure were protected after 13 challenges (p = 0.0088 and 0.0077 compared to placebo, respectively). The calculated PrEP and PEP efficacy was 91.0% (95% CI = 32.2%-98.8%) and 100% (95% CI = undefined), respectively.

INTERPRETATION

Inserts containing TAF/EVG provided high protection against vaginal SHIV infection when administered within a 4 h window before or after SHIV exposure. Our results support the clinical development of TAF/EVG inserts for on-demand PrEP and PEP in women.

FUNDING

Funded by CDC intramural funds, an interagency agreement between CDC and USAID (USAID/CDC IAA AID-GH-T-15-00002), and by the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) through the U.S. Agency for International Development (USAID) under a Cooperative Agreement (AID-OAA-A-14-00010) with CONRAD/Eastern Virginia Medical School.

Informations de copyright

Published by Elsevier B.V.

Déclaration de conflit d'intérêts

Declaration of interests J.G.G.-L. and W.H. are named in US. Government (USG) patents on “Inhibition of HIV infection through chemoprophylaxis” and in US. Government patent applications on “HIV postexposure prophylaxis” and “HIV pre-exposure prophylaxis”. W.H. and J.G.G.-L. report royalties or licenses from Mylan, Laurus Generics, TAD Pharma, and CIPLA Limited. M.M.P., O.N.S., T.J.C., V.A., P.G., S.J., G.F.D., and M.R.C. are named in patent applications on “Pharmaceutical compositions and methods of making on demand solid dosage formulations,” inventions that were developed under USAID-funded cooperative agreements. C.W.D., K.N., A.H., C.D., J.M., G.K., and Y.P. report no conflicts. The findings and conclusions of this manuscript are those of the authors and do not necessarily represent the official views of CDC, USAID, PEPFAR, EVMS, or the USG.