Pfizer has ended its collaboration with Sangamo Therapeutics for the development of giroctocogene fitelparvovec, a gene therapy candidate for hemophilia A, despite the therapy achieving its primary endpoint in a Phase III trial last year. This decision by Pfizer has sent Sangamo's stock price plummeting and raises concerns about the future of the gene therapy and Sangamo's financial stability.
The Phase III trial demonstrated a significant reduction in the annualized bleeding rate in adults with moderately severe to severe hemophilia A following treatment with giroctocogene fitelparvovec. However, Pfizer's decision to terminate the partnership suggests a lack of confidence in the commercial potential of the gene therapy, particularly in light of the challenges faced by BioMarin's Roctavian, another hemophilia A gene therapy that has experienced a slow market uptake.
Market Concerns and Existing Treatments
The market for hemophilia A gene therapies is proving to be more challenging than initially anticipated. BioMarin's Roctavian, despite being the first gene therapy approved for hemophilia A, has struggled to gain traction, with sales of only $16 million in the first nine months of 2024. This slow uptake is attributed to the availability of effective existing treatments, such as Roche's Hemlibra, a once-weekly treatment that many patients prefer over the potential risks and uncertainties associated with gene therapy.
Concerns about the durability of the effects of gene therapies like Roctavian and giroctocogene fitelparvovec have also contributed to the cautious adoption by patients and healthcare providers. These therapies are designed to be one-time treatments, but studies have raised questions about how long the therapeutic effects will last.
Sangamo's Financial Outlook
Pfizer's decision to terminate the partnership is a significant blow to Sangamo's financial prospects. Pfizer had already paid Sangamo $70 million upfront to license the candidate and an additional $55 million in milestones. Sangamo CEO Sandy Macrae stated in November that the company could have received up to $220 million in regulatory and commercial milestones from Pfizer over the next two years. With the termination of the agreement, Sangamo will no longer receive these potential payments, exacerbating its existing financial challenges.
As of September, Sangamo had approximately $39 million in cash reserves. Although a subsequent $10 million payment from Genentech and a $20 million deal with Astellas have provided some relief, the company has stated that it only has enough cash to fund operations into the first quarter of 2025. Sangamo is now actively seeking a new partner to advance the giroctocogene fitelparvovec program and secure additional funding.
Future of Giroctocogene Fitelparvovec
Sangamo intends to explore all options for advancing giroctocogene fitelparvovec, including seeking a new collaboration partner. However, Pfizer's decision to abandon the program raises questions about the attractiveness of the gene therapy to other drugmakers. The challenges faced by BioMarin's Roctavian have also made potential partners more cautious about investing in first-generation hemophilia A gene therapies. The company faces an uphill battle to secure the necessary funding and expertise to bring the gene therapy to market.
