Precigen says Phase 1/2 PRGN-2012 study met primary endpoints

Precigen released Phase 1/2 pivotal study results for the investigational PRGN-2012 off-the-shelf AdenoVerse gene therapy in patients with recurrent respiratory papillomatosis. Results were presented in a late-breaking oral presentation at the 2024 American Society of Clinical Oncology Annual Meeting by Scott M. Norberg, DO, Associate Research Physician, Center for Immuno-Oncology, Center for Cancer Research, National Cancer Institute and a lead investigator for the PRGN-2012 clinical study. The Company will host a webcast event today at 6:00 PM CT / 7:00 PM ET to detail the results presented at ASCO. The Phase 1/2 clinical study evaluated safety and efficacy of PRGN-2012. The study design included an initial 3+3 dose escalation cohort to identify the recommended Phase 2 dose. Adult RRP patients who had three or more surgeries in the prior 12 months were eligible for the study. The Phase 1/2 study enrolled a total of 38 patients. Of these, 3 patients received four administrations of PRGN-2012 at 1x 1011 particle units/dose and 35 patients received four administrations of PRGN-2012 at RP2D over a 12 week treatment period via subcutaneous injection. Primary endpoints included safety and Complete Response rate defined as the percentage of patients who require no RRP surgeries in the 12-month period after PRGN-2012 treatment completion. Key secondary endpoints included HPV-specific immune responses, extent of papilloma growth as measured by Derkay scoring, and quality of life measurement as measured by Vocal Handicap Index-10. Baseline patient characteristics of the 35 adult patients included a median age of 49 years; 20 of the patients were male and 15 were female. Patients had a median of 4 surgeries in the 12 months before PRGN-2012 treatment initiation. Average years since RRP diagnosis was 20 with 12 and 23 patients with juvenile and adult onset RRP, respectively. Primary efficacy endpoint analysis demonstrated that 51% patients achieved Complete Response, defined as no need for RRP surgeries in the 12-month period following completion of PRGN-2012 treatment. PRGN-2012 treatment showed significant improvement in anatomical Derkay scores, a tool used for research purposes to quantify RRP severity based on involvement of laryngeal structures, with mean Derkay scores reducing from 9 at baseline to 1 at 24 weeks post-treatment in patients with Complete Response.