06:33 AM EDT, 08/15/2025 (MT Newswires) -- Precigen ( PGEN ) shares rose more than 33% in premarket activity Friday after the US Food and Drug Administration approved Papzimeos for adults with recurrent respiratory papillomatosis.

The non-replicating adenoviral vector-based immunotherapy is the first FDA-approved therapy for the rare disease which often requires repeated surgeries to remove benign tumors in the respiratory tract, FDA said.

The approval is based on results of a single-arm open label trial in adults who needed at least three surgeries a year, showing 51% of patients achieved a complete response with no further surgical intervention needed for a year, the regulator said.

The safety profile was favorable with no treatment-related serious adverse events reported, FDA said.

FDA granted the approval under priority review and the product received both orphan drug designation and breakthrough therapy designation.