The U.S. Food and Drug Administration on Friday approved Sanofi SA’s (NASDAQ:SNY) Qfitlia (fitusiran), the first antithrombin-lowering (AT) therapy for routine prophylaxis to prevent or reduce the frequency of bleeding episodes in adult and pediatric patients (aged 12 or older) with hemophilia A or B with or without factor VIII or IX inhibitors.

The approval is based on data from the ATLAS phase 3 studies that demonstrated clinically meaningful bleed protection as measured by annualized bleeding rates (ABR).

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By lowering AT, a protein that inhibits blood clotting, Qfitlia helps increase thrombin generation to restore hemostasis in hemophilia patients.

In the ATLAS clinical development program, Qfitlia demonstrated low bleed rates across subgroups with as few as six injections a year. Key results include:

• Significant bleed reduction by 71% in ABR for patients without inhibitors treated with Qfitlia prophylaxis compared to clotting factor concentrate on-demand and by 73% in ABR compared to bypassing agent on-demand for patients with inhibitors (estimated mean: ABR 5.1 vs. 19.1, respectively).
• Median observed ABR during the open-label extension study was 3.8 in patients without inhibitors and 1.9 in patients with inhibitors.
• The median annualized spontaneous bleeding rate observed during the open-label extension study was 1.9 in patients without inhibitors and 1.9 in patients with inhibitors.
• Nearly half of the patients in the open-label extension study experienced one or fewer bleeds (31% zero bleeds and 47% 0-1 bleeds).

With the Qfitlia approval, the FDA cleared the Siemens Healthineers' INNOVANCE Antithrombin assay as a companion diagnostic for Qfitlia to measure AT levels.

Qfitlia is a small interference RNA therapeutic that utilizes Alnylam Pharmaceutical Inc.'s (NASDAQ:ALNY) ESC-GalNAc conjugate technology.

Through the Qfitlia Testing Program with Labcorp, the FDA-cleared companion diagnostic will be available to patients prescribed Qfitlia to measure AT levels at no cost.

A regulatory submission for Qfitlia for hemophilia A or B in adults and adolescents with or without inhibitors is under review in Brazil. A regulatory decision is expected in China in the second half of 2025.

Price Action: SNY stock is down 1.74% at $54.85 during the premarket session at the last check Monday.

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