Assessing Fitusiran for Hemophilia in ATLAS-INH: Guy Young, MD

“The conclusion was that the drug was very effective, it really lowered the bleeding rates quite dramatically by clinically important levels and safety overall was really quite good, though not without its safety concerns.”

FItusiran, a siRNA therapeutic targeting antithrombin, reduced bleeding in people with hemophilia A or B with or without inhibitors treated with prophylactic doses compared with those only given on-demand treatment.

These data, from the phase 3 ATLAS-INH study (NCT03417102), were presented at the 63rd Annual American Society of Hematology (ASH) Meeting, December 11-14, 2021, by Guy Young, MD, director, Hemostasis and Thrombosis Program, Children’s Hospital of Los Angeles and professor of Pediatrics, Keck School of Medicine, University of Southern California.

Most patients with both hemophilia A and B (n = 25; 65.8%) in the fitusiran arm had zero bleeding events after treatment. Patients in this arm achieved statistical significance in the primary endpoint of reduced annual bleeding rate (ABR) of treated bleeds as well as a reduction in all, spontaneous, and joint bleeds. Participants treated with fitusiran also had higher physical health domain and health-related quality of life scores (both P <.0001). Adverse events (AEs) were common and 17.1% (n = 7) of patients reported serious AEs.

GeneTherapyLive spoke with Young to learn more about the ATLAS-INH study. He discussed the efficacy of fitusiran but also safety concerns that still persist.

REFERENCE

Young G, Srivastava A, Kavkli K, et al. Efficacy and safety of fitusiran prophylaxis, an siRNA therapeutic, in a multicenter phase 3 study (ATLAS-INH) in people with hemophilia A or B, with inhibitors (PwHI). Presented at: 63rd Annual ASH Meeting; December 11-14, 2021, Atlanta, GA. Abstract 4.