Precigen announces long-term follow-up results highlighting ongoing durable complete responses after treatment with Papzimeos (zopapogene imadenovec-drba) , the first and only FDA-approved therapy for adults with recurrent respiratory papillomatosis

Precigen Inc. announced long-term follow-up data demonstrating durable responses to Papzimeos (zopapogene imadenovec-drba) for the treatment of adults with recurrent respiratory papillomatosis (RRP). These data were presented at the American Academy of Otolaryngology–Head and Neck Surgery Foundation (AAO-HNSF) 2025 Annual Meeting. Papzimeos  was granted full approval by the FDA in August 2025, becoming the first and only approved therapy for the treatment of adults with RRP.

Results from the pivotal clinical study of  Papzimeos were published in The Lancet Respiratory Medicine (see citation).

Key data highlights from the AAO-HNSF presentation included:

• •15 out of the 18 complete responders (83%) in the pivotal study demonstrated ongoing complete responses as of the September 19, 2025 data cutoff, with:
  • •Median duration of follow-up of 36 months (range: 27-37 months);
  • •Median duration of complete response yet to be reached; and
  • • No new safety events observed during long-term follow-up.
• • Prolonged reduction in the requirement for surgical intervention to manage RRP was observed throughout long-term follow-up of evaluable study patients compared to the year prior to treatment. The percent of patients with a decrease in the number of surgeries, compared to pre-treatment was:
  • •86% in Year 1;
  • •91% in Year 2  and
  • •95% in Year 3.