DNA immunotherapy for recurrent respiratory papillomatosis (RRP): phase 1/2 study assessing efficacy, safety, and immunogenicity of INO-3107

Recurrent respiratory papillomatosis (RRP) is a chronic airway disease caused by Human Papillomavirus (HPV). INO-3107, DNA immunotherapy designed to elicit T-cells against HPV-6 and HPV-11, was evaluated in a 52-week Phase 1/2 study for efficacy, safety, and immunogenicity (NCT04398433). Thirty-two eligible adults with HPV-6 and/or HPV-11 RRP, requiring ≥2 surgical interventions in the year preceding dosing were enrolled between October 2020 and November 2021 and administered 4 INO-3107 doses by intramuscular injection followed by electroporation. The primary endpoint was safety and tolerability, as assessed by treatment-emergent adverse events (TEAEs). Secondary endpoints included surgical intervention frequency and change in RRP Severity Score (modified) post-INO-3107 and assessment of immune responses. 81% (26/32) of patients experienced surgery reduction following INO-3107 compared with the year prior to treatment. Blood assessments revealed HPV-6 and HPV-11 antigen-specific T-cell induction. RNA sequencing identified an inflammatory response in papillomas, inclusive of cytolytic CD8 + T-cell signatures. T-cell receptor sequencing revealed emergent T-cell clones in blood and confirmed trafficking to papillomas. Treatment-related adverse events (AEs) were reported in 13/32 (41%) patients, all low-grade. INO-3107 provides clinical benefit to HPV-6 and/or HPV-11-associated RRP adults and is well-tolerated. Importantly, treatment-induced peripheral T-cell responses traffic to airway tissue and are associated with clinical response.