Victory! FDA Approves Pfizer's Hemophilia A or B Antibody Drug Marstacimab

Pfizer —after facing a showdown with an activist investor, experiencing betrayal by two former executives, and then reuniting with them, while discontinuing work on an RSV drug—finally has some straightforward good news.

On Friday, the FDA approved Pfizer's hemophilia A or B drug marstacimab, which will be marketed under the brand name Hympavzi. The therapy is an anti-tissue factor pathway inhibitor that helps hemophilia patients form clots to limit their bleeding episodes.

In an email to Endpoints News, a Pfizer spokesperson said that the wholesale acquisition cost for this once-weekly medication is $795,600 per year, "which is consistent with the WAC pricing of currently available preventive treatments for hemophilia A or B." The company plans to launch sales of the drug this quarter.

The drug comes in a pre-filled autoinjector pen, which analysts suggest could help it gain traction in the market.

"Given that factor replacement is already well-established, and marstacimab's improvements over standard prevention are moderate, Pfizer will have to rely to some extent on the convenience argument to gain traction," TD Cowen analysts wrote in a report to investors during the American Society of Hematology meeting last December.

The FDA approved Hympavzi for routine prevention to reduce or prevent bleeding events in adults and children as young as 12 years old. It is suitable for patients with hemophilia A without factor VIII inhibitors or hemophilia B without factor IX inhibitors.

This approval expands Pfizer's portfolio in rare blood disorders. In April, the FDA approved the company's hemophilia B gene therapy, Beqvez. After touting results from a Phase 3 trial in July, Pfizer is also seeking approval for a hemophilia A gene therapy. However, the company may face a challenging commercialization process, as evidenced by BioMarin's struggles with its drug, Roctavian.

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