FDA Approves Sanofi’s Qfitlia for Prophylaxis in Patients with Hemophilia A or B

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The FDA has approved Sanofi’s Qfitlia (fitusiran), the first antithrombin-lowering therapy indicated for routine prophylaxis to prevent or reduce bleeding episodes in patients aged 12 years and older with hemophilia A or B, with or without inhibitors. According to the company, Qfitlia demonstrated significant bleed reduction in the Phase III ATLAS clinical development program.¹

“Current treatment options can make people with hemophilia feel they need to choose between effective bleed control and convenient dosing schedules, leading to trade-offs when it comes to disease management,” said Phil Gattone, president, CEO, National Bleeding Disorders Foundation, in a press release. “Qfitlia takes a novel approach to providing protection for people living with hemophilia while reducing the frequency of dosing for patients and their families.”

The ATLAS clinical development program includes the completed ATLAS-INH, ATLAS-A/B, and ATLAS-PPX trials, as well as the ATLAS-NEO, ATLAS-PEDS, and ATLAS OLE studies, all of which are currently in progress. The single-arm, open-label, ATLAS OLE study is currently evaluating the safety and efficacy of Qfitlia with a revised antithrombin (AT)-based dosing regimen. The treatment regimen aims to keep AT levels between 15% and 35% in patients who previously participated in an ATLAS study.

Results showed Qfitlia reduced annualized bleeding rates (ABR) by 71% in patients without inhibitors and by 73% in those with inhibitors. The median ABR was 3.8 in patients without inhibitors and 1.9 in those with inhibitors. Additionally, both groups had a median annualized spontaneous bleeding rate of 1.9. Nearly half of participants experienced one or fewer bleeds, with 31% having no bleeds at all.

Sanofi warns that treatment with Qfitlia could potentially result in serious adverse events (AEs), including thrombotic events, acute and recurrent gallbladder disease, and hepatotoxicity. The most common AEs include viral infection, nasopharyngitis, and bacterial infection.

In line with the approval, the FDA also approved the Siemens Healthineers’ Innovance Antithrombin assay as a companion diagnostic to monitor AT levels. It is expected to be available to patients treated with Qfitlia at no additional cost.¹

According to data from the Centers for Disease Control and Prevention (CDC), approximately 33,000 males are currently living with hemophilia in the United States. An estimated four out of every 10 males have severe hemophilia. In females, bleeding symptoms are usually found to be less severe than in males, but they may experience reduced joint range of motion compared to healthy females.

CDC data also show that hemophilia A is three to four times more common than hemophilia B. The median diagnosis age is around three years of age in patients with mild hemophilia, eight months of age in patients with moderate hemophilia, and one month in cases of severe hemophilia. In two-thirds of all cases, there is a family history of hemophilia. In the other one-third, there is no known family history, with a diagnosis first made when the bleeding is discovered.²

“Qfitlia delivers the fewest doses of any prophylactic therapy in hemophilia, and its unique mechanism allows it to be used to treat all types of hemophilia, including with inhibitors and hemophilia B, where unmet medical needs remain,” said Guy Young, MD, director, hemostasis and thrombosis center, Children's Hospital, Los Angeles, in the press release. “By targeting antithrombin, which can be reliably measured with an FDA-cleared blood assay, Qfitlia is proven to help rebalance hemostasis and improve bleed rates and protection.”

References

1. Press Release: Qfitlia approved as the first therapy in the US to treat hemophilia A or B with or without inhibitors. Sanofi. March 28, 2025. Accessed March 31, 2025. https://www.sanofi.com/en/media-room/press-releases/2025/2025-03-28-20-07-38-3051637

2. Data and Statistics on Hemophilia. CDC. Accessed March 31, 2025. https://www.cdc.gov/hemophilia/data-research/index.html