Recombinant ADAMTS13 Effective, Safe in Congenital Thrombotic Thrombocytopenic Purpura

THURSDAY, May 2, 2024 (HealthDay News) -- Prophylaxis with recombinant ADAMTS13 in patients with congenital thrombotic thrombocytopenic purpura (TTP) leads to ADAMTS13 activity reaching approximately 100 percent of normal levels, according to a study published in the May 2 issue of the New England Journal of Medicine.

Marie Scully, M.D., of the University College London Hospitals, and colleagues conducted a phase 3, open-label, crossover trial in which patients with congenital TTP were randomly assigned (1:1) to prophylaxis with recombinant ADAMTS13 (40 IU/kg of body weight given in two six-month periods) or standard therapy, followed by the alternate treatment. All patients then received recombinant ADAMTS13 for an additional six months. Thirty-two patients completed the trial.

The researchers found that no acute TTP event occurred during the ADAMTS13 prophylaxis treatment, and one patient in the standard therapy arm had an acute TTP event. Adverse events occurred in 71 percent of patients in the ADAMTS13 prophylaxis group and 84 percent of the standard therapy group. There were no trial-drug interruptions or treatment discontinuations due to adverse events noted in the ADAMTS13 prophylaxis group compared with eight in the standard therapy group. The mean maximum ADAMTS13 activity after the ADAMTS13 prophylaxis treatment was 101 percent compared with 19 percent after standard therapy. No neutralizing antibodies developed during the ADAMTS13 prophylaxis treatment.

"The better safety and higher average ADAMTS13 activity levels observed with recombinant ADAMTS13 than with standard therapy in this clinical trial may, in clinical practice, help expand patient access to long-term prophylaxis," the authors write.

The study was funded by Takeda, the manufacturer of recombinant ADAMTS13.

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