Pfizer has announced the termination of its collaboration with Sangamo Therapeutics on the development of giroctocogene fitelparvovec, an investigational gene therapy for hemophilia A. This decision comes despite positive Phase 3 AFFINE trial results, which met primary and key secondary endpoints, demonstrating the therapy’s potential efficacy.
Background
The partnership, established in 2017, aimed to develop a one-time gene therapy to enable hemophilia A patients to produce factor VIII, a clotting protein they lack. In July 2024, Pfizer reported that the Phase 3 AFFINE trial achieved its primary and key secondary objectives, indicating the therapy’s superiority compared to prophylaxis.
Pfizer’s Decision
Despite the promising clinical data, Pfizer has chosen not to proceed with the Biologics License Application (BLA) and Marketing Authorisation Application (MAA) submissions for giroctocogene fitelparvovec. The company cited a comprehensive review of clinical trial results, expert feedback, and a slow uptake of hemophilia A gene therapies among patients with moderate to severe disease as factors influencing its decision. Pfizer indicated that there is currently limited interest in another gene therapy option for this patient population and expressed a strategic shift towards assets with greater potential impact and commercial success.
Impact on Sangamo Therapeutics
As a result of Pfizer’s withdrawal, Sangamo will regain full development and commercialization rights to giroctocogene fitelparvovec. The termination of the collaboration and license agreement is set to take effect on April 21, 2025. Sangamo has expressed surprise and disappointment at Pfizer’s decision, especially given the compelling pivotal clinical trial data. The company plans to explore all options to advance the program, including seeking a new collaboration partner to bring this potential treatment to patients.
Market Reaction
Following the announcement, Sangamo’s stock experienced a significant decline, plummeting nearly 64% in extended trading. This sharp drop reflects investor concerns about the future prospects of the hemophilia A gene therapy program and Sangamo’s ability to advance it without Pfizer’s support.
Future Outlook
Despite this setback, Sangamo remains committed to its broader genomic medicine pipeline. The company is focusing on advancing its Fabry disease gene therapy program, with plans for a potential BLA submission in the second half of 2025. Sangamo’s management emphasizes their dedication to exploring the optimal path forward for giroctocogene fitelparvovec, aiming to find the right partner to bring this promising treatment to the hemophilia A patient community.
