A Phase IV, Open-label, Single-Arm, Multicentric Clinical Trial for Evaluation of Human Papillomavirus 9vHPV Vaccine Immunogenicity in Men Who Have Sex With Men With HIV: GeSIDA Study 10 017

Background Men who have sex with men (MSM) with HIV are at increased risk for anal cancer, largely attributable to persistent HPV infection. However, data on the nonavalent HPV vaccine (9vHPV) in MSM with HIV older than 26 remain sparse. Methods This phase IV trial evaluated the immunogenicity, safety, and impact of age and CD4/CD8 ratio on 9vHPV vaccine responses in MSM with HIV up to 35 years. Inclusion criteria were age 16–35, undetectable viral load, and CD4 + counts >200 cells/mm³. Participants received 9vHPV vaccine doses at weeks 0, 8, and 24, and were followed to week 96. Serum samples for immunogenicity, anal HPV DNA testing, and adverse event reports were collected at baseline, week 28, and week 96. Additionally, we investigated potential predictors of vaccine immunogenicity, including age group and CD4/CD8 ratio. Results Among 158 enrolled participants, 138 completed the per-protocol analysis. Seroconversion exceeded 85% for all nine HPV vaccine genotypes at week 96. New infections with vaccine-included genotypes occurred in 24% of participants, predominantly involving HPV-16. The overall clearance rate for any high-risk HPV genotype included in the vaccine was 74% at week 96. Neither older age (≥26 years), lower CD4/CD8 ratio, nadir CD4 or CD4 counts affected immunogenicity. No severe adverse events related to vaccination were recorded. Conclusions The 9vHPV vaccine demonstrated robust immunogenicity and encouraging viral clearance rates in MSM with HIV up to 35 years. These findings support extending vaccination beyond 26 years in this high-risk group, emphasizing the additional coverage provided by the 9vHPV formulation. Clinical Trial Registration EudraCT number 2018–000215-24.