Topline Findings
- FDA grants full approval to Papzimeos for recurrent respiratory papillomatosis (RRP): Papzimeos becomes the first and only approved therapy for adults with RRP, targeting the root cause of the disease.
- Pivotal trial shows strong and durable results: 51% of patients achieved a complete response with no surgeries needed at one year, with most maintaining benefit at two years.
- Well-tolerated safety profile: No dose-limiting toxicities were reported with only mild to moderate treatment-related adverse events.
The FDA has granted full approval to Precigen’s Papzimeos (zopapogene imadenovec-drba) for adults with recurrent respiratory papillomatosis (RRP). Papzimeos is a non-replicating adenoviral vector-based immunotherapy that was engineered to produce a fusion antigen that contains key segments of HPV types six and 11 proteins.
Papzimeos marks the first-and-only treatment to be FDA-approved for RRP. Full approval was based on results from a pivotal Phase I/II trial (NCT04724980) led by The National Institutes of Health(NIH).1
How Could Papzimeos Change the Treatment Landscape for RRP?
"For more than a century, since RRP was first recognized as a distinct disease, patients have had to rely on repeated surgeries to manage this relentless condition,” said Helen Sabzevari, PhD, president, CEO, Precigen, in a press release. “Today marks a historic turning point. With the landmark FDA approval of Papzimeos and broad label, all adult RRP patients are now eligible for access to the first and only approved therapy that targets the root cause of the disease. This milestone affirms the power of our AdenoVerse platform and the exceptional capabilities of our team to rapidly advance a wholly novel therapy from discovery to approval considerably faster than industry benchmarks.
“We are profoundly grateful to the NIH clinicians, the FDA, and—most importantly—the patients and families who made this breakthrough possible. We look forward to swiftly delivering Papzimeos to the RRP community and ushering in a new era of treatment that targets the underlying cause of the disease rather than just managing its symptoms."
Key Findings from the Pivotal Trial
- The open-label, single-arm, pivotal trial evaluated the safety and tolerability of Papzimeos in 38 patients with RRP.
- The dual primary endpoints of the trial were to determine the percentage of patients who achieved a complete response (CR) following treatment with Papzimeos as well as determining the incidence of dose limiting toxicities.
- Key secondary endpoints included, but were not limited to, safety at the recommended Phase II dose, immune responses, change in vocal function scores over time, and overall response rate.2
- Results showed that 51% of patients achieved a CR, requiring no surgeries one-year post-treatment.
- Fifteen patients continued to achieve a CR at the two-year mark.
- Papzimeos was reported to be well tolerated, with no dose-limiting toxicities and no treatment-related adverse events (AEs) higher than grade 2.1
- The most common AEs included injection site reactions, fatigue, chills, and fever.3
“Randomized trials are not always needed to approve medical products and this approval is proof of that philosophy,” said Vinay Prasad, MD, MPH, director, Center for Biologics Evaluation and Research (CBER), in a press release. “The FDA will always demand the correct clinical study for the specific medical product and disease. Our requirements for products given to tens of millions of healthy people will be different than products given to at most hundreds or thousands of patients with unique diseases.”4
Disease Background
RRP is most common in patients aged two to four years and those aged 20 to 40 years, affecting an estimated four in 100,000 children and two in 100,000 adults.5
"This long-awaited FDA approval represents a momentous milestone for the RRP community," said Kim McClellan, president, Recurrent Respiratory Papillomatosis Foundation, in a press release. "For the first time, adult patients with RRP have access to an FDA-approved therapy that offers the potential to reduce—or even eliminate—endless repeated surgeries. This breakthrough brings long-overdue hope to patients and families who have endured so much. We are deeply grateful to the teams at Precigen and the NIH, and above all, to the patients and caregivers whose courage, advocacy, and perseverance have made this historic moment possible."
References
- Precigen Announces Full FDA Approval of PAPZIMEOS (zopapogene imadenovec-drba), the First and Only Approved Therapy for the Treatment of Adults with Recurrent Respiratory Papillomatosis. PR Newswire. August 15, 2025. Accessed August 15, 2025. https://prnmedia.prnewswire.com/news-releases/precigen-announces-full-fda-approval-of-papzimeos-zopapogene-imadenovec-drba-the-first-and-only-approved-therapy-for-the-treatment-of-adults-with-recurrent-respiratory-papillomatosis-302530957.html
- Adjuvant PRGN-2012 in Adult Patients With Recurrent Respiratory Papillomatosis. Clinicaltrials.gov. Accessed August 15, 2025. https://clinicaltrials.gov/study/NCT04724980
- PRGN-2012 gene therapy in adults with recurrent respiratory papillomatosis: a pivotal phase 1/2 clinical trial. The Lancet. Accessed August 15, 2025. https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(24)00368-0/abstract
- FDA Approves First Immunotherapy for Recurrent Respiratory Papillomatosis. FDA. August 14, 2025. Accessed August 15, 2025. https://www.fda.gov/news-events/press-announcements/fda-approves-first-immunotherapy-recurrent-respiratory-papillomatosis
- Recurrent respiratory papillomatosis. HPV World. Accessed August 15, 2025. https://www.hpvworld.com/articles/recurrent-respiratory-papillomatosis/
