Sangamo Therapeutics (SGMO) was plunging 49% in extended trading, after saying Monday it will regain full development and commercialization rights for giroctocogene fitelparvovec after Pfizer (PFE) decided to terminate the collaboration and licensing agreement for the prospective hemophilia A gene therapy.

The partnership between Sangamo and Pfizer will formally end on April 21, 2025, Sangamo said. It plans on exploring all options to continuing to advance the program, including finding a new collaboration partner.

The companies will also continue to monitor participants in a phase 3 trial of drug candidate during the transition period, it said.

Pfizer shares were fractionally lower in the after-hours session.