Whew.
Pfizer — after a week in which it began a showdown with an activist investor, was betrayed by and then reunited with two former top executives, and ended work on an RSV drug — finally has some good, straightforward news.
On Friday, the FDA approved Pfizer’s hemophilia A or B drug marstacimab, which will be sold under the brand name Hympavzi. The treatment is an anti-tissue factor pathway inhibitor that aids in blood clot formation in hemophilia patients to limit their bleeding episodes.
The once-weekly medicine will have an annual wholesale acquisition cost of $795,600, “which is in line with current WAC pricing for prophylactic treatments for hemophilia A or B currently available on the market,” a Pfizer spokesperson said in an email to Endpoints News. It plans to begin selling the drug this quarter.
The drug is packaged as a pre-filled, auto-injector pen, which analysts have said could help it find a place in the market.
“Given that factor replacement is well-established, and marstacimab improvement over routine prophylaxis was modest, Pfizer will have to rely to some extent on the convenience argument to gain traction,” TD Cowen analysts wrote in a note to investors during last December’s American Society of Hematology conference.
The FDA approved Hympavzi for routine prophylaxis to prevent or reduce bleeding episodes in adults and children as young as 12 years old. It’s indicated for patients with hemophilia A without factor VIII inhibitors, or hemophilia B without factor IX inhibitors.
It will add to Pfizer’s portfolio in rare blood diseases. In April, the FDA cleared the drugmaker’s hemophilia B gene therapy Beqvez. Pfizer is also planning to request approval of a hemophilia A gene therapy after touting Phase 3 results in July, but it could face a tough commercialization rollout given the struggles BioMarin has faced with its medicine Roctavian.
New type of medicine
Instead of replacing a clotting factor like other hemophilia treatments, Hympavzi reduces a naturally occurring anticoagulation protein. That leads to more thrombin, a key piece of blood clotting.
“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,” Ann Farrell, director of the Division of Non-Malignant Hematology in the FDA’s Center for Drug Evaluation and Research, said in a statement.
An open-label Phase 3 study called BASIS served as the foundation for the FDA’s decision.
Pfizer originally outlined the BASIS results in May 2023. After 12 months, the medicine helped reduce the annualized bleeding rate for treated bleeds by 35% and 92% compared to routine prophylaxis and on-demand treatment, respectively, for patients without inhibitors.
The European Medicines Agency’s medical products committee also gave a positive opinion for the drug last month.
Another cohort testing the medicine with inhibitors is expected to have results in the third quarter of next year, Pfizer has said. That group could be key to the medicine’s future.
“Given once-weekly dosing and no obvious efficacy or safety advantage, this agent likely will not compete with Roche’s Hemlibra in hemophilia A, but could carve out a niche in hemophilia B pending data in patients with inhibitors,” the TD Cowen analysts said in their note.
Multiple other companies are working in hemophilia. Novo Nordisk’s hemophilia A and B treatment candidate concizumab was rejected in May 2023. In May of this year, another Novo medicine, called Mim8, cleared a Phase 3a in hemophilia A.