Slog, Stefani A.

ABSTRACT Objective To evaluate the long‐term safety and clinical effect of INO‐3107 immunotherapy in adults with recurrent respiratory papillomatosis (RRP). Methods RRP‐002 was a retrospective, observational extension study that followed patients enrolled in the 52‐week RRP‐001 study. Patients with moderate to severe juvenile or adult‐onset RRP who had undergone ≥ 2 surgical interventions in the year preceding dosing were eligible for enrollment in RRP‐001. Participants underwent surgical debulking within 14 days prior to initial dosing and then received INO‐3107 on Day 0, Weeks 3, 6, and 9. Efficacy assessments during RRP‐002 follow‐up were the frequency of surgical interventions and alternative medication use. The safety evaluation included reported serious adverse events (SAEs). Results Twenty‐eight (28) of 32 participants from the 52‐week RRP‐001 study were enrolled in RRP‐002. The median follow‐up time for RRP‐002 was 1.8 years (range: 1.2–2.4 years) for a total median assessment time of 2.8 years (range: 1.0–3.5 years). There were no SAEs or long‐term safety concerns identified. The mean number of surgeries was reduced from 4.1 in the pre‐treatment period to 1.7 in the first year post‐INO‐3107 treatment (Year 1) to 0.9 in the second year (Year 2). The complete response rate (0 surgeries per year) increased from 28% (9/32) in Year 1 to 50% (14/28) in Year 2. Conclusion INO‐3107 is well tolerated and provides a continued clinical effect against HPV‐6 and 11 RRP that results in further reduction of the surgical burden observed in Year 1. These data support the role of INO‐3107 immunotherapy for adult patients with RRP. Level of Evidence: III.