Adeno-Associated Virus Vectored Immunoprophylaxis to Prevent HIV: A Phase 1 Randomized Controlled Trial in Healthy Adults

Abstract

Background: A preventive vaccine for HIV is a critical public health need. Adeno-associated virus (AAV) mediated antibody gene delivery could be an alternative to immunization to induce sustained expression of neutralizing antibodies to prevent HIV. We conducted a first-in-human, phase 1 study of rAAV1-PG9DP, a recombinant AAV1 vector encoding the gene for PG9, a broadly neutralizing antibody against HIV. Methods: The trial was a phase 1, randomized, blinded, placebo-controlled, dose-escalation study at a single center in the UK. Healthy, HIV-uninfected men aged 18-45 were randomly assigned (3:1) to intervention or control in one of four dose-escalating cohorts (4x1012 vector genomes(vg), 4x1013 vg, 8x1013 vg or 1·2x1014 vg). Volunteers received intramuscular injection with rAAV1-PG9DP or placebo in the deltoid or quadriceps and were followed for 48 weeks. The primary objective was safety and tolerability. A secondary objective was to evaluate PG9 expression in serum and related HIV neutralization activity. This trial is registered with ClinicalTrials.gov, number NCT01937455. Findings: 21 volunteers were enrolled between February 10, 2014 and February 28, 2017 and completed 48 weeks follow-up. Reactogenicity was generally mild or moderate and self-limited. There were no probably or definitely related adverse events and no serious adverse events. We detected PG9 by HIV neutralization in serum of four volunteers, and by RT-PCR in muscle biopsies of four volunteers. We did not detect PG9 by ELISA in serum. PG9 anti-drug antibody was present in 10 volunteers in the higher dose groups. Both anti-AAV1 antibodies and AAV1 specific T-cell responses were detected. Interpretation: Intramuscular administration of rAAV1-PG9DP in healthy men was safe and well-tolerated. Antibody expression was detected directly in muscle and indirectly in serum, and anti-drug antibodies were induced, indicating PG9 expression. Future studies should explore higher doses of AAV, alternative AAV serotypes and gene expression cassettes, or other broadly neutralizing HIV antibodies. Trial Registration number: This trial is registered with ClinicalTrials.gov, number NCT01937455. Funding: International AIDS Vaccine Initiative, United States Agency for International Development (USAID), Bill & Melinda Gates Foundation, US National Institutes of Health Declaration of Interest: Jim Ackland reports receiving consulting fees from International AIDS Vaccine Initiative during the course of the study. Fraser Wright reports grants from National Institutes of Health during the conduct of the study. In addition, Dr. Wright has a patent US 9,408,904 licensed to Spark Therapeutics. Ethical Approval: The protocol was approved by the University of Surrey Ethics Committee, the NRES Bristol Research Ethics Committee and the UK Medicines and Healthcare products Regulatory Authority and conducted in compliance with Good Clinical Practices and the Declaration of Helsinki guidelines.