HYMPAVZI granted priority review for the treatment of two Hemophilia A or B patient populations

Pfizer has recently announced that the U.S. FDA has accepted and granted Priority Review for the company’s supplemental Biologics License Application for HYMPAVZI to expand the approved indication to include the treatment of hemophilia A or B patients 6 years and older with inhibitors, and pediatric patients with hemophilia A or B without inhibitors. HYMPAVZI is currently approved for the treatment of patients 12 years of age and older with hemophilia A without factor VIII inhibitors, or hemophilia B without factor IX inhibitors in the U.S.

Note that the FDA has set a Prescription Drug User Fee Act action date in the second quarter of 2026. If approved, HYMPAVZI would offer a combination of bleed protection with a straightforward, once-weekly subcutaneous injection administration, requiring minimal preparation and no routine treatment-related lab monitoring for these difficult-to-treat patient populations.

“There is a significant medical need for younger patients with hemophilia and for those who have developed inhibitors, which neutralize factor replacement therapies and render them ineffective,” said Michael Vincent, M.D., Ph.D., Chief Inflammation & Immunology Officer, Pfizer. “Based on the findings in the BASIS clinical trial program and if approved, we believe HYMPAVZI has the potential to become a transformative option for these patients that have limited or burdensome treatment options today. We look forward to progressing discussions with regulators to make this medicine available for patients.”

“For children living with hemophilia A or B between ages 6 and 11, treatment approaches that prevent bleeds are particularly important to protect growing joints,” said Guy Young, M.D., Director, Hemostasis and Thrombosis Center at Children’s Hospital, Los Angeles. “HYMPAVZI would address a critical unmet medical need for these patients and those with inhibitors if approved, particularly patients ages 6 to 11 with hemophilia B who do not have non-factor treatment options available today.”

Note that the FDA grants Priority Review to medicines that may offer significant advances in treatment or may provide a treatment where no adequate therapy exists. Priority Review designation by the FDA shortens the standard sBLA review period by four months.

The FDA also granted HYMPAVZI Breakthrough Therapy Designation for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in younger pediatric patients with hemophilia B with and without inhibitors to expedite the development and review of medicines with the potential to treat a serious or life-threatening disease, when preliminary clinical evidence indicates the medicine may demonstrate substantial improvement over existing therapies.

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Related Topics and Keywords

Hemophilia A or B, hympavzi, HYMPAVZI® (marstacimab)