** U.S. biotech firm Precigen's PGEN.O shares rise 5.5% to $3.29 premarket

** Co says its drug Papzimeos showed durable response in adults with recurrent respiratory papillomatosis (RRP), a rare respiratory disease that causes benign tumor growth in the airways

** Durable response means patients stayed symptom-free without needing repeat surgeries for years

** PGEN says 83% of patients with complete response to Papzimeos stayed surgery-free after 3 years

** Co says 95% of patients needed fewer surgeries in year 3 compared to the year before starting Papzimeos

** In August, Papzimeos became the first FDA-approved therapy for adults with RRP

** Up to last close, stock up ~179% YTD

(Reporting by Sahil Pandey)

((Sahil.Pandey@thomsonreuters.com))