Effect of Tenofovir on Genital Herpes Simplex Virus (HSV) Shedding

The investigators propose a randomized, double-blind, placebo-controlled, cross-over study of 55 adult, healthy women who are HSV-2 seropositive and HIV-1 seronegative. Women will first participate in a run-in phase with twice daily swabbing. Following 4 weeks of swabbing, participants will be randomized 2:2:1 to one of three groups: 1) oral tenofovir and placebo gel, 2) oral placebo and tenofovir gel, or 3) oral placebo and placebo gel. Participants will begin treatment and swab the genital region twice daily for 5 more weeks. Study drug will be administered daily.

Inclusion criteria

• Women age 18-50
• HSV-2 seropositive by the University of Washington (UW) Western blot
• History of recurrent genital herpes, with more than 4 recurrences but less than 10 in the last year or, if currently on suppressive therapy, with more than 4 recurrences but less than 10 in the year prior to starting suppressive therapy
• HIV negative
• General good health
• Willing to not use antiviral therapy (other than the study drug) for the duration of the study
• Willing to obtain a swab from genital secretions twice daily for the duration of the study
• Willing to use effective birth control
• Able to provide written informed consent at screening and enrollment

Exclusion criteria

• HIV positive or at high risk for HIV acquisition (intravenous drug user or HIV+ sex partner)
• Hepatitis B (HepB) antigen (Ag) positive, or at high risk for HepB acquisition and not vaccinated
• Have a history of adverse reaction to tenofovir and/or adefovir
• Immunosuppressive medications, except for intranasal or topical (not high potency) steroids.
• Any kidney disease, or renal insufficiency, defined as serum creatinine >1.5 mg/dl. Participants with a prior history of a single episode of pyelonephritis will be eligible.
• Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 3 times upper limit of normal
• Pregnancy, as confirmed by a urine pregnancy test, planning to become pregnant during the course of the trial, or breast-feeding.
• Serious medical conditions or active infections
• Any other conditions that in the judgment of the investigator would preclude successful completion of the clinical trial.