A study involving women at risk of HIV infection has discontinued a comparison of daily Viread (tenofovir) pre-exposure prophylaxis (PrEP) to placebo, in light of expert projections that the clinical trial will not be able to demonstrate effectiveness, according to a September 28 Microbicide Trials Network (MTN) announcement. The Vaginal and Oral Interventions to Control the Epidemic (VOICE) study will, however, continue evaluating the safety and efficacy of another oral tablet, Truvada (tenofovir plus emtricitabine), along with a vaginal microbicide containing tenofovir.