Precigen shares jump after US FDA approves first therapy for rare respiratory disease

By Sneha S K and Kamal Choudhury

Aug 15 (Reuters) - Precigen's PGEN.O immunotherapy for a rare respiratory disease has become the first treatment to win U.S. regulatory approval for the condition, which typically requires frequent surgeries, sending the company's shares soaring 83% on Friday.

The U.S. Food and Drug Administration has approved the therapy, Papzimeos, to treat adults with recurrent respiratory papillomatosis (RRP) — a condition that causes growth of benign tumors in the respiratory tract due to human papillomavirus (HPV) infection.

A distinguishing aspect of RRP is the tendency for the tumors to return even after removing them through surgical procedures. The disease can be fatal as there is no cure.

The FDA approval was based on an early-to-mid-stage study data that showed 51% of patients required no surgeries in the 12 months after the treatment.

"Randomized trials are not always needed to approve medical products and this approval is proof of that philosophy," said Vinay Prasad, who recently returned to the FDA to oversee vaccine, gene therapy and blood product regulation.

Papzimeos is designed to stimulate an immune response against cells infected with HPV types 6 and 11 — the strains that cause the disease. H.C. Wainwright analysts estimate peak sales of the drug to reach $1.1 billion in 2033.

"We may finally be able to say no more surgery," said Kim McClellan, president of the Recurrent Respiratory Papillomatosis Foundation. McClellan herself was diagnosed with RRP at the age of five and has since then had more than 250 surgeries.

Precigen estimates about 27,000 adult RRP patients in the U.S. It did not immediately respond to a Reuters request for comment on the treatment's pricing.

Simon Best, associate professor of Otolaryngology at Johns Hopkins Hospital, said patients were eagerly awaiting a new treatment.

"There's nothing more frustrating than doing a surgery and then having the patient come back six months later."