Sanofi Announces FDA Approval of Enjaymo (sutimlimab), the First and Only C1s Inhibitor for Cold Agglutinin Disease

Recently, Sanofi announced that the FDA has approved sutimlimab (brand name: Enjaymo) for marketing to reduce red blood cell transfusion requirements due to hemolysis in patients with cold agglutinin disease (CAD). This is the first FDA-approved complement C1s antibody for the treatment of CAD.

Hemolysis in cold agglutinin disease is driven by the classical complement pathway, and sutimlimab is the first monoclonal antibody targeting the C1s protein in the classical complement pathway. It works by blocking the function of the C1s protein in the classical complement pathway, inhibiting hemolysis caused by the activation of complement proteins in patients. Additionally, sutimlimab has received Breakthrough Therapy Designation and Priority Review status from the FDA.

The approval was based on data from a single-arm pivotal Phase III clinical trial that lasted for 26 weeks. The trial enrolled a total of 24 subjects, with the primary endpoint being the proportion of patients who achieved either an increase in hemoglobin (Hgb) levels of at least 2 g/dL from baseline or reached a normalized Hgb level above 12 g/dL at the evaluation time points (the average of weeks 23, 25, and 26), and who did not require a blood transfusion from week 5 to week 26.

The results showed that the majority of patients (54%; n=13) met the primary composite endpoint criteria, 63% of patients (n=15) achieved hemoglobin ≥12 g/dL or an increase of at least 2 g/dL; 71% of patients (n=17) remained transfusion-free after the fifth week; and 92% of patients (n=22) did not require other CAD-related treatments.