title: Intravaginal ring eluting tenofovir disoproxil fumarate completely protects macaques from multiple vaginal simian-HIV challenges.
abstract: Topical preexposure prophylaxis interrupts HIV transmission at the site of mucosal exposure. Intermittently dosed vaginal gels containing the HIV-1 reverse transcriptase inhibitor tenofovir protected pigtailed macaques depending on the timing of viral challenge relative to gel application. However, modest or no protection was observed in clinical trials. Intravaginal rings (IVRs) may improve efficacy by providing long-term sustained drug delivery leading to constant mucosal antiretroviral concentrations and enhancing adherence. Although a few IVRs have entered the clinical pipeline, 100% efficacy in a repeated macaque vaginal challenge model has not been achieved. Here we describe a reservoir IVR technology that delivers the tenofovir prodrug tenofovir disoproxil fumarate (TDF) continuously over 28 d. With four monthly ring changes in this repeated challenge model, TDF IVRs generated reproducible and protective drug levels. All TDF IVR-treated macaques (n = 6) remained seronegative and simian-HIV RNA negative after 16 weekly vaginal exposures to 50 tissue culture infectious dose SHIV162p3. In contrast, 11/12 control macaques became infected, with a median of four exposures assuming an eclipse of 7 d from infection to virus RNA detection. Protection was associated with tenofovir levels in vaginal fluid [mean 1.8 × 10(5) ng/mL (range 1.1 × 10(4) to 6.6 × 10(5) ng/mL)] and ex vivo antiviral activity of cervicovaginal lavage samples. These observations support further advancement of TDF IVRs as well as the concept that extended duration drug delivery devices delivering topical antiretrovirals could be effective tools in preventing the sexual transmission of HIV in humans.
authors.affiliation: Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, Sexually Transmitted Disease, and Tuberculosis Prevention, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333.
authors.forename: James M
authors.initials: JM
authors.lastname: Smith
authors.forename: Rachna
authors.initials: R
authors.lastname: Rastogi
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Teller
authors.forename: Priya
authors.initials: P
authors.lastname: Srinivasan
authors.forename: Pedro M M
authors.initials: PM
authors.lastname: Mesquita
authors.forename: Umadevi
authors.initials: U
authors.lastname: Nagaraja
authors.forename: Janet M
authors.initials: JM
authors.lastname: McNicholl
authors.forename: R Michael
authors.initials: RM
authors.lastname: Hendry
authors.forename: Chuong T
authors.initials: CT
authors.lastname: Dinh
authors.forename: Amy
authors.initials: A
authors.lastname: Martin
authors.forename: Betsy C
authors.initials: BC
authors.lastname: Herold
authors.forename: Patrick F
authors.initials: PF
authors.lastname: Kiser
mesh_terms: D000225:Adenine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D000282:Administration, Intravaginal; D000818:Animals; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems / Q000379:methods*; D005260:Female; D006678:HIV / Q000187:drug effects*; D016180:Lentivirus Infections / Q000517:prevention & control*; D008253:Macaca mulatta; D063065:Organophosphonates / Q000008:administration & dosage / Q000494:pharmacology*; D015302:Simian Immunodeficiency Virus / Q000187:drug effects*; D000068698:Tenofovir
chemical_list: D003692:Delayed-Action Preparations; D063065:Organophosphonates; D000068698:Tenofovir; D000225:Adenine
keywords: PrEP; controlled drug delivery; nonhuman primate; pharmacokinetics
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