A drug evaluation of 1% tenofovir gel and tenofovir disoproxil fumarate tablets for the prevention of HIV infection.

Introduction: More than a million people acquire HIV infection annually. Pre-exposure prophylaxis (PrEP) using antiretrovirals is currently being investigated for HIV prevention. Oral and topical formulations of tenofovir have undergone preclinical and clinical testing to assess acceptability, safety and effectiveness in preventing HIV infection. Areas covered: The tenofovir drug development pathway from compound discovery, preclinical animal model testing and human testing were reviewed for safety, tolerability and efficacy. Tenofovir is well tolerated and safe when used both systemically or applied topically for HIV prevention. High drug concentrations at the site of HIV transmission and concomitant low systemic drug concentrations are achieved with vaginal application. Coitally applied gel may be the favored prevention option for women compared with the tablets, which may be more suitable for prevention in men and sero-discordant couples. However, recent contradictory effectiveness outcomes in women need to be better understood. Expert opinion: Emerging evidence has brought new hope that antiretrovirals can potentially change the course of the HIV epidemic when used as early treatment for prevention, as topical or oral PrEP. Although some trial results appear conflicting, behavioral factors, adherence to dosing and pharmacokinetic properties of the different tenofovir formulations and dosing approaches offer plausible explanations for most of the variations in effectiveness observed in different trials

Development of a Composite Measure of Product Adherence, Protocol Compliance, and Semen Exposure Using DNA and Protein Biomarkers for Topical HIV Prevention Studies

Poor and inconsistent use of study products has hindered clinical HIV prevention studies. It is important to be able to monitor product adherence and protocol compliance in order to determine microbicide efficacy and safety more accurately. Current methods for monitoring adherence are subjective, non-specific, or invasive. Herein, we present a composite, objective measure of product adherence and protocol compliance to assess vaginal insertion, semen exposure and drug expulsion utilizing DNA, protein, and drug isolated directly from returned, vaginally used gel applicators.DNA, vaginal cells, and residual tenofovir were isolated from vaginally inserted applicators. Vaginal and semen biomarkers were amplified using a multiplex PCR to determine vaginal insertion. Vaginal cells were fixed followed by cytokeratin 4 immunocytochemistry to confirm DNA assessment of vaginal insertion. Tenofovir was extracted and quantitated through LC-MS/MS.DNA isolated from vaginally inserted applicators were positive for vaginal bacteria DNA and the control eukaryotic gene, amelogenin, while manually handled, "sham", applicators were negative for both. Semen exposure was independently determined by simultaneous amplification of one or both Y-chromosomal genes, SRY and TSPY4. Vaginal insertion determination by DNA analysis was further confirmed by positive cytokeratin 4 (CK4) immunocytochemistry of vaginal cells remaining on the gel applicators. On the contrary, sham applicators provided very few cells when swabbed, and they were all negative for CK4. CK4 was not found in epidermal cells from the hand. Drug expulsion was detected through quantitation of residual gel present on the surface of returned applicators. Sham applicators had no detectable tenofovir.Utilizing a composite, triple marker based panel of DNA, protein, and drug present on the surface of returned vaginal gel applicators, it is possible to determine, objectively and non-invasively, product adherence, protocol compliance, and semen exposure in microbicide trials

Plasma Concentrations, Efficacy and Safety of Efavirenz in HIV-Infected Adults Treated for Tuberculosis in Cambodia (ANRS 1295-CIPRA KH001 CAMELIA Trial).

To assess efavirenz plasma concentrations and their association with treatment efficacy and tolerance of efavirenz 600 mg daily in HIV-tuberculosis co-infected patients