FDA Approves First Gene Therapy for Recurrent Respiratory Papillomatosis
Terry Flotte, MD - August 21, 2025
This new therapy not only transforms the treatment landscape for RRP but also demonstrates the continued evolution of CGTs in addressing rare diseases.
For patients suffering from recurrent respiratory papillomatosis (RRP), FDA recently reached a milestone: The Agency approved Precigen’s Papzimeos (zopapogene imadenovec-drba), the first and only therapy approved for this devastating rare disease. This approval represents not only a scientific breakthrough, but also newfound hope for thousands of patients who have endured countless surgeries throughout their lives.
RRP is a rare, chronic disease caused by infection with human papillomavirus (HPV) types 6 or 11, which leads to the growth of tumors in the larynx and respiratory tract. These wart-like growths are officially classified as benign because they are not cancerous, but they cause significant morbidity for patients. The tumors result in voice disturbances, breathing difficulties, chronic cough, and difficulty swallowing. Until now, patients’ only treatment option was repeated surgical procedures to remove the growths, often requiring dozens or even hundreds of surgeries over their lifetimes. For patients with the most severe disease, they may require surgery every few weeks on order to keep their airway open for breathing. The disease affects approximately 27,000 adults in the United States, with roughly 1,000 new cases diagnosed annually. The disease can appear in either juveniles or adults, with pediatric patients often experiencing more aggressive symptoms.
Papzimeos targets the underlying viral cause of RRP rather than merely managing symptoms. This non-replicating adenoviral vector-based immunotherapy is designed to stimulate the patient's immune system to recognize and attack cells infected with HPV types 6 and 11. Administered as four subcutaneous injections over 12 weeks, Papzimeos offers the potential for long-term disease control through a single treatment course.
The approval is based on results from a single-arm, open-label pivotal study in adult patients with RRP who required three or more surgeries per year. Among the 35 patients evaluated, 51% achieved a complete response, defined as no need for surgical intervention in the 12 months following treatment. Follow-up data demonstrated that these responses were durable, with 15 of the 18 patients in complete response maintaining their response through two years. The pivotal trial was led by investigators from the National Institutes of health, demonstrating the importance of strong federal research infrastructure.
This approval carries particular regulatory significance, as it illustrates the pathway for innovative clinical trial design in therapies with significant unmet medical need. As noted by Dr. Vinayak Prasad, director of the FDA's Center for Biologics Evaluation and Research, "Randomized trials are not always needed to approve medical products and this approval is proof of that philosophy. … 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.&rdquo
For the RRP community, this approval brings long-awaited hope. This new therapy not only transforms the treatment landscape for RRP but also demonstrates the continued evolution of gene and cell therapies in addressing rare diseases.
Join Dr. Flotte and other expert presenters Sept. 25-26 at the ASGCT Policy Summit, where thought leaders will discuss how the policy landscape influences CGT development and approval.
Register to join us in Washington, D.C.!
Dr. Flotte is ASGCT President, provost and executive deputy chancellor of UMass Chan Medical School, and dean of the T.H. Chan School of Medicine.
Related Articles