The Encore1 study.
Research type
Research Study
Full title
A randomised, double-blind, placebo-controlled, clinical trial to compare the safety and efficacy of reduced dose efavirenz (EFV) with standard dose EFV plus two nucleotide reverse transcriptase inhibitors (N(t)RTI) in antiretroviral-naïve HIV-infected individuals over 96 weeks.
IRAS ID
27132
Contact name
Brian Gazzard
Eudract number
2009-013795-44
Clinicaltrials.gov Identifier
Research summary
Efavirenz (EFV) is a type of anti-HIV medication called a non-nucleoside reverse transcriptase inhibitor (NNRTI). NNRTIs block reverse transcriptase, a protein that HIV needs to make more copies of itself. Clinical data suggests that the standard dose of EFV may be reduced without compromising its effectiveness. Lower drug doses could have fewer side effects and would also make EFV more affordable. The purpose of this study is to compare the safety and effectiveness of standard (600mg) versus reduced dose (400mg) as part of initial combination antiretroviral therapy in HIV-infected patients over 96 weeks.In this international, multicenter trial enrolling 630 HIV-infected patients who have not received any treatment for their HIV. Participants will be randomly allocated (1:1) to receive Truvada (tenofovir and emtricitabine) with either the standard or reduced dose of EFV. Neither the study doctor nor the participant will know which treatment the participant's receiving. Physical examinations, laboratory analyses and questionnaires will be performed at the 11 study visits at screening, baseline (Week 0), Weeks 4, 12, 24, 36, 48, 60, 72, 84 and 96. The primary aim of this study is to compare between treatment groups the proportion of patients with undetectable HIV viral load (HIV RNA < 200 copies/mL) after 96 weeks. Information will also be collected on immune function, resistance to antiretrovirals, quality of life, brain function and HIV-related conditions. Blood samples will be collected for future testing. Provisional analyses will be performed when the first 125 participants in each treatment group reach week 24 and when all participants reach week 24. These provisional analyses will provide an early check that the reduced dose of EFV suppresses HIV infection as effectively as the standard dose of EFV.
REC name
London - Fulham Research Ethics Committee
REC reference
10/H0711/53
Date of REC Opinion
15 Jul 2010
REC opinion
Further Information Favourable Opinion