Approval is based on a study in 116 adult and pediatric male patients with either severe hemophilia A or severe hemophilia B, both without inhibitors.
The FDA has approved marstacimab-hncq (Hympavzi; Pfizer) to reduce or prevent bleeding episode frequency in adult and pediatric patients aged 12 years and up with hemophila A without factor VIII inhibitors, or hemophilia B without factor IX inhibitors, according to the FDA.1
With this decision, marstacimab-hncq becomes the first and only anti-tissue factor pathway inhibitor approved in the United States to treat hemophilia A or B, and is the first hemophilia medicine approved in the United States to be administered via a pre-filled, auto-injector pen, stated Pfizer in a press release.2
“Today’s approval of Hympavzi provides patients with hemophilia a new treatment option that is the first of its kind to work by targeting a protein in the blood clotting process," said Ann Farrell, MD, director, Division of Non-Malignant Hematology, Center for Drug Evaluation and Research, FDA, in a statement.1
"This new type of treatment underscores the FDA’s commitment to advance the development of innovative, safe and effective therapies," Farrell added.1
The genetic bleeding disorders are the result of a dysfunction or deficiency of coagulation factor VIII, or IX. Patients with these hemophilias cannot clot properly and could bleed for a longer time than normal after an injury or surgery. These patients can also have spontaneous bleeding in joints, muscles, and organs, which could be life-threatening.1
“The approval of [marstacimab-hncq] is a meaningful advancement for people living with hemophilia A or B without inhibitors for bleed prevention, with a generally manageable safety profile and a straightforward once-weekly subcutaneous administration,” said Suchitra S. Acharya, MD.2
Acharya is the director of the Hemostasis and Thrombosis Center Northwell Health, and the program head of the Bleeding Disorders and Thrombosis Program at Cohen Children's Medical Center.2
"[Marstacimab-hncq] aims to reduce the current treatment burden by meeting an important need for these patients, including many who have required frequent, time-consuming intravenous treatment infusion regimens," said Acharya.2
Approval was supported by the phase 3 BASIS trial (NCT03938792), which included adults and adolescents with hemophilia A or B without inhibitors.2 For the first 6 months of this study, patients received treatment with replacement factor either on-demand (33 patients) or prophylactically (83 patients), according to the FDA.1
Patients then received marstacimab-hncq prophylaxis for 12 months, with the primary measure of efficacy being the annualized bleeding rates of treated bleeds. In patients "receiving on-demand factor replacement during the first [6] months of the study, the estimated annualized bleeding rate was 38 compared to the estimated annualized bleeding rate during treatment with [marstacimab-hncq] of 3.2," the federal agency stated.1
According to Pfizer, the most commonly reported adverse reactions (≥3% of patients) included injection site reactions, pruritus, and headache. Marstacimab-hncq, which was granted Orphan Drug Designation by the FDA, comes with warnings and precautions about circulating blood clots, hypersensitivity, and embryofetal toxicity.1,2
"The hemophilia community continually seeks advancements in care that can improve quality of life for our community members," said Phil Gattone, president and CEO, National Bleeding Disorders Foundation. "The availability of this therapy represents a powerful step forward in advancing care for more individuals and families in the bleeding disorders community.”2
References:
1. FDA approves new treatment for hemophilia A or B. FDA. Press release. October 11, 2024. Accessed October 11, 2024. https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-hemophilia-or-b?utm_medium=email&utm_source=govdelivery
2. U.S. FDA Approves Pfizer’s HYMPAVZI™ (marstacimab-hncq) for the Treatment of Adults and Adolescents with Hemophilia A or B Without Inhibitors. Pfizer. Press release. October 11, 2024. Accessed October 11, 2024. https://www.businesswire.com/news/home/20241009505480/en/U.S.-FDA-Approves-Pfizer%E2%80%99s-HYMPAVZI%E2%84%A2-marstacimab-hncq-for-the-Treatment-of-Adults-and-Adolescents-with-Hemophilia-A-or-B-Without-Inhibitors