Pfizer Gains FDA Approval for Hemophilia Treatment Despite Activist Investor Resistance

Pictured: Pfizer office at its South San Francisco
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The U.S. Food and Drug Administration (FDA) has recently approved Pfizer’s new treatment for hemophilia A and B, named Hympavzi. This approval marks Hympavzi as the first once-weekly subcutaneous prophylactic injection available for hemophilia B in the United States. Additionally, it is the first treatment offered in a pre-filled pen or syringe for both hemophilia A and B.

Hympavzi is designed to manage hemophilia by reducing the frequency or entirely preventing bleeding episodes in patients. It is indicated for routine prophylaxis and is administered once a week via subcutaneous injection. The treatment is suitable for hemophilia A patients without factor VIII inhibitors and hemophilia B patients without factor IX inhibitors.

Suchitra Acharya, head of the Bleeding Disorders and Thrombosis Program at Cohen Children’s Medical Center, commented on the significance of Hympavzi’s approval. Acharya described it as a meaningful advancement for individuals living with hemophilia A or B, highlighting the ongoing challenges they face, including persistent bleeding and the burdensome nature of current treatment regimes.

Hympavzi’s approval is supported by data from the Phase III BASIS trial, an open-label study involving nearly 190 patients with severe hemophilia A or moderately severe to severe hemophilia B. The trial demonstrated a 92% reduction in bleeding episodes for patients without inhibitors to factor VIII or factor IX. Furthermore, the annual bleeding rate among these patients dropped by 35%.

Hympavzi is an IgG1 monoclonal antibody that targets the Kunitz domain 2 of the tissue factor pathway inhibitor (TFPI) protein. Under normal conditions, this protein prevents blood clotting. By targeting the TFPI protein, Hympavzi enhances coagulation, helping to manage bleeding episodes in hemophilia patients.

This regulatory approval strengthens Pfizer’s hemophilia portfolio, which already includes the gene therapy Beqvez, approved by the FDA in April 2024 for moderate to severe hemophilia B. Pfizer is also developing another gene therapy, giroctocogene fitelparvovec, for hemophilia A, with Phase III data released in July 2024 showing it to be both non-inferior and superior to regular Factor VIII infusions.

Pfizer is currently navigating challenges posed by activist investor Starboard Value. Recently, Starboard Value acquired a $1 billion stake in Pfizer and expressed intentions to replace CEO Albert Bourla and alter the company's strategic direction. Despite this, former Pfizer CEO Ian Read and former CFO Frank D’Amelio have expressed their support for the current leadership.

In summary, the FDA’s approval of Hympavzi represents a significant advancement in the treatment of hemophilia A and B, offering a new, more convenient option for patients. This development is poised to improve the quality of life for many individuals living with hemophilia, reflecting Pfizer’s ongoing commitment to innovation in the field.