FDA approves Pfizer’s HYMPAVZI for breakthrough hemophilia treatment

In a major leap for hemophilia patients, Pfizer Inc. (NYSE: PFE) announced that the U.S. Food and Drug Administration (FDA) has granted approval for HYMPAVZI (marstacimab-hncq) to prevent or reduce bleeding episodes in individuals aged 12 and above with hemophilia A or B without inhibitors. This marks a groundbreaking advancement in the treatment landscape for hemophilia patients, particularly with HYMPAVZI being the first and only anti-tissue factor pathway inhibitor (anti-TFPI) approved for this indication in the United States. The approval of HYMPAVZI is expected to transform the management of hemophilia, offering a new, innovative option for patients who have long been burdened by time-consuming and invasive treatment protocols.

The First Subcutaneous Auto-Injector for Hemophilia A and B

HYMPAVZI is set to revolutionize hemophilia treatment with its easy-to-use pre-filled, auto-injector pen. It offers a once-weekly subcutaneous injection, emphasizing both convenience and simplicity. This not only simplifies treatment but reduces the preparation and time burden traditionally faced by hemophilia patients who have long relied on frequent intravenous infusions. Unlike traditional therapies, HYMPAVZI’s auto-injector technology provides a more patient-friendly approach that could enhance adherence and improve overall quality of life.

Dr. Suchitra Acharya, Director of the Hemostasis and Thrombosis Center at Northwell Health, stated that the approval of HYMPAVZI offers a less complex and more manageable bleeding prevention option for patients without inhibitors. She noted that HYMPAVZI’s weekly dosing schedule could ease the treatment burden faced by many patients, potentially allowing them to lead more normal lives with fewer disruptions. Dr. Acharya also highlighted the potential for HYMPAVZI to change the standard of care for hemophilia patients by reducing the frequency of medical interventions needed.

A Solution to Frequent Bleeding Challenges

Hemophilia—a rare genetic disorder affecting over 800,000 people worldwide—inhibits the blood’s ability to clot, leading to repeated bleeding episodes and potential joint damage. These repeated bleeds, particularly in joints, can lead to significant long-term complications, including chronic pain and mobility issues. Despite advancements in care, many people with hemophilia still face frequent bleeds and often rely on demanding intravenous treatment regimens that require careful planning and significant time commitments. The need for an alternative that reduces both the physical and logistical challenges of managing hemophilia has been a long-standing concern within the community.

Pfizer’s Chief U.S. Commercial Officer, Aamir Malik, highlighted HYMPAVZI’s significance as Pfizer’s second hemophilia treatment to gain FDA approval this year, demonstrating their commitment to hemophilia care. Malik emphasized Pfizer’s ability to offer a diverse range of treatments, including anti-TFPI, gene therapy, and recombinant factor therapies, to address the unique needs of various patients. He underscored the importance of expanding the treatment toolkit for hemophilia to ensure that patients have access to therapies that suit their individual needs, ultimately aiming to improve their quality of life and health outcomes.

Clinical Data Supporting HYMPAVZI Approval

The approval of HYMPAVZI was based on positive results from the Phase 3 BASIS trial (NCT03938792), which evaluated its efficacy and safety, showing significant reductions in bleeding rates. During the trial, HYMPAVZI demonstrated significant reductions in the annualized bleeding rate (ABR) for treated bleeds compared to routine prophylaxis and on-demand treatment. Specifically, the study found that HYMPAVZI reduced bleeding episodes by up to 35% compared to routine prophylaxis and by 92% compared to on-demand treatment. The safety profile was consistent with previous trial phases, and the most common side effects included injection site reactions, headaches, and itching. These findings underscore the potential of HYMPAVZI to offer meaningful clinical benefits to patients who have struggled with frequent bleeding episodes despite existing treatments.

The ongoing inhibitor cohort study is expected to provide further insights into the safety and efficacy of HYMPAVZI in patients with hemophilia with inhibitors, with results expected by Q3 2025. The results of this study could pave the way for expanded use of HYMPAVZI in an even broader patient population, further solidifying its role in the treatment landscape for hemophilia.

Expert Opinion: A Step Forward for the Hemophilia Community

Phil Gattone, President and CEO of the National Bleeding Disorders Foundation, said that Pfizer’s innovative efforts with HYMPAVZI address several key challenges that hemophilia patients face today. He stressed that the availability of a novel treatment like HYMPAVZI represents a powerful stride forward in enhancing quality of life for individuals in the bleeding disorders community. Gattone also noted that the simplicity of the auto-injector and the reduction in treatment frequency are game-changers for patients, potentially reducing the mental and emotional toll of managing the condition. He emphasized that such innovations can provide hope to patients and their families who have long awaited more convenient and effective treatment options.

Expanding Global Reach and Ongoing Studies

Besides the U.S. FDA approval, Pfizer also received a positive opinion from the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA). This approval is for marstacimab in adolescents and adults with hemophilia A or B. The approval from CHMP is an important milestone that reflects the robust clinical data supporting marstacimab’s efficacy and safety, and it opens the door for broader access to this innovative treatment in European countries. Additionally, Pfizer is progressing with its pediatric study, BASIS KIDS, which investigates the safety and efficacy of marstacimab in children aged 1-18 years. The inclusion of younger patients in these studies is critical, as it could eventually expand the use of HYMPAVZI to a more comprehensive age group, ensuring that even the youngest patients can benefit from advances in hemophilia treatment.

Pfizer’s Hemophilia Portfolio Strengthens

HYMPAVZI is a testament to Pfizer’s more than 40-year commitment to hemophilia care. Earlier this year, Pfizer secured approvals for its gene therapy BEQVEZ (fidanacogene elaparvovec) for hemophilia B across the U.S., EU, and Canada. The approval of BEQVEZ was a landmark achievement, showcasing Pfizer’s dedication to gene therapy as a transformative approach to managing genetic disorders like hemophilia. Their expanding range of treatment options positions Pfizer as a major player in providing comprehensive solutions for hemophilia patients worldwide, ensuring that patients have access to a variety of innovative therapies that cater to different needs and preferences. By offering multiple classes of therapies—including gene therapy, anti-TFPI treatment, and recombinant factors—Pfizer is uniquely positioned to address the diverse challenges faced by people living with hemophilia, ultimately aiming to improve treatment outcomes and quality of life for patients at all stages of life.