Caplacizumab Accelerates Platelet Count Normalization in Adults With aTTP

Relief for Patients With Life-Threatening Blood-Clotting Disorder

Positive results from the phase 3 trial of caplacizumab (Cablivi; Sanofi) in adults with acquired thrombotic thrombocytopenia purpura (aTTP) were published in the New England Journal of Medicine.

Caplacizumab (Cablivi; Sanofi) is a bivalent anti-von Willebrand factor (vWF) nanobody for adults with aTTP. One of the first therapeutics to receive approval for aTTP, it blocks the formation and buildup of micro-clots that cause thrombocytopenia, tissue ischemia, and organ damage in patients with the condition.

Thrombotic thrombocytopenic purpura (TTP) is a rare autoimmune disorder caused by lack of activity in the ADAMTS13 enzyme, responsible for proper clotting activity. Acquired TTP is caused by certain antibodies that impede ADAMTS13 enzyme activity in the body.

In the HERCULES (NCT02553317) trial, patients with aTTP were randomized to receive caplacizumab or placebo in conjunction with plasma exchange and immunosuppression. The primary outcome was the time to normalization of platelet count, with discontinuation of daily plasma exchange within 5 days following. 

Data showed that the median time to platelet count normalization was shorter with caplacizumab compared to placebo (2.69 days vs. 2.88 days; P = 0.01). Patients receiving caplacizumab were 1.55 times more likely to achieve normal platelet counts compared with those who received placebo. 

Also, compared with placebo, treatment with caplacizumab resulted in a lower incidence of aTTP-related death, aTTP recurrence, or a thromboembolic event during the trial (74% reduction), as well as a lower rate of aTTP recurrence at any time during the trial (67% reduction). 

The Prescription Drug Fee User Act target date is set for February 6, 2019.

Source: Drug Development Technology, January 10, 2019; MPR, January 10, 2019.