The First Immunotherapy for Recurrent Respiratory Papillomatosis: Papzimeos Receives FDA Approval
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A Historic FDA Approval for RRP
Recurrent respiratory papillomatosis (RRP)is a rare but serious disease caused by HPV 6 and 11. Benign tumors develop in the larynx and airways, but recur repeatedly. Frequent surgery impairs quality of life and may cause major voice and breathing problems. Until now, RRP had no approved medical treatment.
💡 On 14 August 2025, the FDA announced approval of Papzimeos, a new immunotherapy. This marks a historic treatment milestone.
🫁 What Is Recurrent Respiratory Papillomatosis (RRP)?
RRPis a rare disease caused by HPV types 6 and 11, producing benign wart-like airway tumors. Most occur on the vocal cords in the larynx, causing hoarseness, breathlessness and chronic cough . Rapid growth, particularly in children, can seriously disrupt breathing during sleep.
- Responsible HPV Types: HPV 6 and 11
- Transmission: Sexual contact or mother-to-child transmission during birth
- Frequency: Approximately 2 cases per 100,000 children
- Treatment: Surgery remains the main approach; frequent recurrence may require multiple operations annually
💊 What Is Papzimeos?
- Active Ingredient: Zopapogene imadenovec-drba
- Mechanism: Nonreplicating adenoviral vector-based immunotherapy
- Administration: Subcutaneous injection
- Target: Activate immunity against cells infected with HPV 6 and 11
- 📌 Marketing Authorization Holder: Precigen, Inc.
➡️ Beyond surgery-based approaches, it is the first option targeting the immune system.
📊 Clinical Trial Data
Papzimeos, investigated as PRGN-2012, was approved based on a study published in The Lancet Respiratory Medicine in April 2025: a pivotal Phase 1/2 trial (DOI:10.1016/S2213-2600(24)00368-0).
The single-center, single-arm, open-label trial enrolled adults requiring at least three operations in the previous year for RRP. Following surgical debulking, everyone received 4 subcutaneous doses (on days 1, 15, 43 and 85).
- Patient Numbers: From March 2021 – June 2023, 38 patients were enrolled; 35 received the recommended Phase 2 dose of 5×1011 viral particles.
- Primary Outcome: No surgery needed for 12 months (complete response).
Findings
- 51% (18/35) Complete Response: Half required no further surgery for 12 months (95% CI 34–69).
- Response Duration: Median duration had not been reached; most responses persisted for 2 years.
- Immune Response: HPV 6/11-specific T-cell activation correlated strongly with clinical benefit.
- Safety: Adverse effects were mostly mild-to-moderate. Most common:
- 97% injection-site reactions
- 80% fatigue
- 71% chills
- 69% fever
Conclusion: PRGN-2012 eliminated surgery requirements for 12 months in 51% of adults with RRP and was found safe. A biologics license application followed, and approval as Papzimeos came in August 2025.
🌍 What Does This Approval Mean?
- The US sees approximately 1,000 new RRP cases annually.
- Despite rarity, the disease can devastate quality of life.
- The approval begins a new era beyond dependence on repeated surgery for patients.
💬 FDA official Dr. Vijay Kumar: "This approval could transform RRP treatment and offer lasting relief to patients dependent on repeated surgery."
✅ In Summary: Papzimeos is the first FDA-approved RRP immunotherapy. Half of patients avoided surgery, with long-lasting activity, a major development for rare-disease care.
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