Feasibility and Successful Enrollment in a Proof-of-Concept HIV Prevention Trial of VRC01, a Broadly Neutralizing HIV-1 Monoclonal Antibody

BACKGROUND: The Antibody Mediated Prevention (AMP) trials (HVTN 704/HPTN 085 & HVTN 703/HPTN 081) are the first efficacy trials to evaluate whether VRC01, a broadly neutralizing monoclonal antibody (mAb) targeting the CD4 binding site of the HIV envelope protein, prevents sexual transmission of HIV-1. HVTN 704/HPTN 085 enrolled 2,701 cisgender men and transgender (TG) individuals who have sex with men at 26 sites in Brazil, Peru, Switzerland and the United States. METHODS: Participants were recruited and retained through early, extensive community engagement. Eligible participants were randomized 1:1:1 to 10 mg/kg or 30 mg/kg of VRC01 or saline placebo. Visits occurred monthly, with intravenous (IV) infusions every 8 weeks over 2 years, for a total of ten infusions. Participants were followed for 104 weeks after first infusion. RESULTS: The median HVTN 704/HPTN 085 participant age was 28; 99% were assigned male sex; 90% identified as cisgender male, 5% as TG female and the remaining as other genders. Thirty-two percent were White, 15% Black and 57% Hispanic/Latinx. Twenty-eight percent had a sexually transmitted infection at enrollment. Over 23,000 infusions were administered with no serious IV administration complications. Overall retention and adherence to the study schedule exceeded 90%, and the drop-out rate was below 10% annually (7.3 per 100-person years) through Week 80, the last visit for the primary endpoint. CONCLUSIONS: HVTN 704/HPTN 085 exceeded accrual and retention expectations. With exceptional safety of IV administration and operational feasibility, it paves the way for future large-scale mAb trials for HIV prevention and/or treatment