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Fall 2022 - Innovation

Fitusiran Prophylaxis Reduces Bleeds Versus Prior Factor or Bypassing Agent Prophylaxis in Hemophilia A and B Patients

Fitusiran targets antithrombin to rebalance hemostasis in people with hemophilia A or B, regardless of inhibitor status.

Prophylaxis with fitusiran, Sanofi’s investigational small interference RNA (siRNA) therapeutic, significantly reduced bleeding in a Phase III multinational study in adults and adolescents with hemophilia A or B, with or without inhibitors, compared to their previous factor or bypassing agent (BPA) prophylaxis. Fitusiran targets antithrombin to rebalance hemostasis in people with hemophilia A or B, regardless of inhibitor status.

Of 65 study participants eligible for annualized bleeding rate (ABR) analyses, 50 had hemophilia A and 15 had hemophilia B; 19 participants had an inhibitor and 46 did not have an inhibitor. Median observed ABRs (interquartile range) were 4.4 (2.2; 10.9) with prior factor or BPA prophylaxis, and 0.0 (0.0; 2.3) with fitusiran prophylaxis. Fitusiran prophylaxis resulted in a 61.1 percent reduction in the estimated ABR versus factor or BPA prophylaxis

Forty-one of the 65 participants (63.1%) treated with 80 mg of subcutaneous fitusiran over a period of seven months experienced zero treated bleeds, compared to 11 (16.9%) of these participants on prior factor or BPA prophylaxis. Fitusiran also significantly improved health-related quality of life (HRQoL) in relation to prior factor or BPA, as measured by the Haem-A-QOL total score. Serious adverse events occurred in five of 65 participants (7.7%) during factor/BPA prophylaxis and nine of 67 (13.4%) during fitusiran prophylaxis. Two participants experienced suspected or confirmed thromboembolic events with fitusiran.


Kenet G, Nolan B, Zulfikar B, et al. A Phase 3 study (ATLAX-PPX) to evaluate efficacy and safety of fitusiran, an siRNA therapeutic, in people with haemophilia A or B who have switched from prior factor or bypassing agent prophylaxis. International Society on Thrombosis and Haemostasis 2022 Congress (Abstract LB 01.1); 2022 July 9-13.

BSTQ Staff
BioSupply Trends Quarterly [BSTQ] is the definitive source for industry trends, news and information for the biopharmaceuticals marketplace. With timely and critical information, each themed issue covers topics ranging from product breakthroughs, industry insights and innovations, up-to-the-minute news on the latest clinical trials, accessibility, and service and safety concerns.