A Randomized, Placebo-Controlled, Dose-Escalation Study to Determine the Safety, Tolerability, and Immunogenicity of an HPV-16 Therapeutic Vaccine in HIV-Positive Participants With Oncogenic HPV Infection of the Anus

Objective: Study aimed to assess safety, tolerability, and immunogenicity of novel therapeutic HPV-16 E6E7 ISCOMATRAX vaccine for treatment of human papilloma virus (HPV)-related anal intra-epithelial neoplasia in HIV-infected men who have sex with men with moderate immunosuppression. Design: Randomized, multicenter, blinded, placebo-controlled, dose-escalating study investigating 3 different doses of vaccine and different dose schedule. Primary objective to determine safety and tolerability, including clinical status, maintenance of virological control, and CD4 cell count for more than 252 days. Results: Thirty-five men who have sex with men enrolled; median age 47 years; current CD4 count 627 cells per milliliter; nadir CD4 count 154 cells per milliliter; 94% current antiretrovirals; 100% high-risk HPV types; 69% abnormal anal cytology; and 34% anal intraepithelial neoplasia 1-3 on high-resolution anoscopy. No dose-limiting toxicities or serious adverse events in HPV-16 vaccine recipients. Most HPV-16 vaccine recipients reported moderate/severe short-term injection site reactions and systemic reactions including headache, myalgia, and fatigue. CD4 cell counts remained stable. Five participants had transiently detectable viral loads. Ninety-six percent of vaccine recipients had at least a 4-fold increase in HPV-16 antibody from prevaccination levels. Seventy-one percent had at least a 3-fold increase in interferon-gamma responses to E6E7 peptides. Conclusions: The novel therapeutic HPV-16 E6E7 ISCOMATRIX vaccine seemed safe and reasonably well tolerated. The therapeutic vaccine induces strong and durable antibody responses and moderate interferon-gamma levels that fell to prevaccination levels by week 24.