Pfizer, Sangamo Gene Therapy Outperforms Routine Prophylaxis in Hemophilia A Study

Pfizer has announced promising results from its Phase III AFFINE study concerning the investigational gene therapy giroctocogene fitelparvovec, aimed at treating adults with moderately severe to severe haemophilia A. The therapy, which could potentially replace routine Factor VIII (FVIII) replacement prophylaxis treatments, has shown significant efficacy in reducing the total annualised bleeding rate (ABR).

The top-line results from the trial revealed that a single 3e13 vg/kg dose of giroctocogene fitelparvovec led to a statistically significant reduction in mean total ABR when compared to the period before the infusion. Specifically, the ABR decreased from 4.73 pre-infusion to 1.24 post-infusion. This represents a substantial improvement in managing the bleeding episodes typically associated with haemophilia A.

Additionally, Pfizer reported that 84% of the participants who received the gene therapy maintained FVIII activity levels above 5% at 15 months post-infusion. The majority of these participants exhibited FVIII activity at or above 15%. Moreover, the mean treated ABR experienced a dramatic reduction of 98.3%, dropping from 4.08 during the pre-infusion period to just 0.07 post-infusion. These findings suggest that giroctocogene fitelparvovec could potentially offer a more efficient and long-term solution for haemophilia A patients.

Giroctocogene fitelparvovec is being developed in collaboration between Pfizer and Sangamo Therapeutics. The therapy consists of a bio-engineered AAV6 capsid and a modified B-domain deleted human coagulation FVIII gene. The single infusion approach of this gene therapy aims to enable individuals to produce FVIII on their own over an extended duration, which could significantly reduce or eliminate the need for regular FVIII replacement treatments.

Pfizer plans to discuss these promising Phase III results with regulatory authorities to explore the potential for bringing this innovative treatment to the market. The company believes that the significant reduction in bleeding rates and the sustained FVIII activity levels could represent a major advancement in the treatment of haemophilia A.