FDA OKs Papzimeos for Respiratory Papillomatosis
FDA has approved a Precigen BLA for Papzimeos (zopapogene imadenovec-drba), which the agency describes as a “first-of-its-kind non-replicating adenoviral vector-based immunotherapy for the treatment of adult patients with recurrent respiratory papillomatosis (RRP).” The rare chronic disease is caused by persistent human papillomavirus (HPV) 6 or 11 infection, leading to benign tumors growing in the respiratory tract, typically the larynx, it says, adding that it is “associated with significant morbidity, including voice changes, breathing difficulties, and airway obstruction.”
Since returning to the agency, CBER director Vinay Prasad noted in an agency press release that: “Randomized trials are not always needed to approve medical products and this approval is proof of that philosophy. 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.”
With an estimated 1,000 new cases diagnosed annually in the U.S., RRP represents a rare disease with significant unmet medical need. Until today, no therapies have been approved for RRP. Papzimeos is administered via subcutaneous injection and is designed to stimulate an immune response against cells infected with HPV types 6 and 11—the causative agents in RRP. The therapy offers a novel mechanism of action distinct from traditional treatments, which have relied primarily on repeated surgical interventions.
The approval is based on data from a single-arm, open-label trial evaluating Papzimeos in adult patients with RRP who required three or more surgeries per year, according to FDA. Patients received four subcutaneous injections of Papzimeos over 12 weeks following surgical debulking (reduction) procedures. It found that 51.4% of treated patients (18/35) achieved a complete response — defined as not needing surgical intervention in the 12 months following treatment. “Follow-up data showed that durable responses were maintained in most patients through two years, with a strong correlation between clinical benefit and the induction of HPV 6/11-specific T cells,” the agency says.
Additionally, FDA says the safety profile was favorable, with most treatment-emergent adverse events being mild to moderate. “No dose-limiting toxicities were observed, and no treatment-related serious adverse events were reported,” it says.