August 19, 2025 — Germantown, MD – Precigen, Inc. (NASDAQ: PGEN) today announced that the U.S. Food and Drug Administration (FDA) has granted full approval to PAPZIMEOS® (zopapogene imadenovec-drba), marking the first and only FDA-approved therapeutic option for adult patients living with recurrent respiratory papillomatosis (RRP).

RRP is a rare, chronic disease caused by persistent infection with human papillomavirus (HPV) types 6 and 11. The condition leads to the growth of benign tumors in the airways, often requiring patients to undergo repeated surgeries to restore normal breathing and speech.

A Breakthrough in Rare Disease Immunotherapy

PAPZIMEOS® is a non-replicating adenoviral vector-based immunotherapy engineered to deliver a fusion antigen designed to stimulate the immune system against HPV 6 and 11. Unlike current standard interventions that focus on removing papillomas surgically, PAPZIMEOS® addresses the underlying viral cause of the disease.

The approved dosing regimen consists of four subcutaneous injections over a 12-week period.

Clinical Evidence and Durability of Response

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The FDA approval is supported by data from a pivotal Phase I/II open-label trial, which demonstrated:

  • 51% of patients achieved a complete response, defined as requiring no surgical intervention for at least 12 months following treatment.
  • Of responders assessed at 24 months, 15 of 18 patients maintained a durable complete response, highlighting long-term benefit potential.
  • No dose-limiting toxicities were reported; treatment was generally well-tolerated with most adverse events described as mild to moderate.

Regulatory Significance

In a notable move, the FDA granted full approval without requiring a confirmatory trial, underscoring the agency’s flexibility in accelerating treatments for rare diseases with significant unmet need. The decision reflects a growing regulatory willingness to balance innovative science with patient access in rare conditions.

Voices from Industry and Advocacy

“This approval represents a historic milestone for patients with RRP, who have had no FDA-approved therapeutic alternatives until now,” said Helen Sabzevari, PhD, President and CEO of Precigen. “For the first time, we are offering a treatment designed to target the root cause of disease rather than just its symptoms.”

Patient advocates echoed this sentiment. Kim McClellan, President of the Recurrent Respiratory Papillomatosis Foundation, noted: “For decades, patients have endured repeated surgeries with no long-term relief. PAPZIMEOS® brings hope for reduced surgical burden and improved quality of life.”

Key Takeaways for the Life Sciences Community

  • First-in-class approval: PAPZIMEOS® becomes the first and only FDA-approved therapy for RRP.
  • Novel mechanism: Immunotherapy targeting HPV 6/11 distinguishes it from surgery-based management.
  • Durable outcomes: More than half of patients achieved long-lasting responses.
  • Regulatory impact: Full approval without confirmatory trial sets precedent for rare disease drug development.

About Precigen
Precigen, Inc. (NASDAQ: PGEN) is a biopharmaceutical company dedicated to advancing the next generation of gene and cell therapies, with a focus on immuno-oncology and rare diseases.

Source: Precigen, Inc.