What was the most frequently reported adverse reaction to FibCLOT (human fibrinogen) in studies of patients with congenital fibrinogen deficiency?

Headache was the most frequently reported adverse reaction to FibCLOT (human fibrinogen) in studies of patients with congenital fibrinogen deficiency, occurring in 1.4% of infusions (9/631), with all cases mild to moderate, occurring within 48 hours and resolving without sequelae.