Recombinant ADAMTS13 (rADAMTS13) appears to confer clinical benefit to patients with immune-mediated thrombotic thrombocytopenic purpura (iTTP), according to research presented at the EHA 2023 Hybrid Congress. The study’s results suggest that further investigation of rADAMTS13 in this population is warranted.

ADAMTS13 deficiency is a hallmark signal of iTTP, a rare thrombotic disorder. While contemporary treatment strategies rely on plasma exchange that replaces ADAMTS13, new therapies are needed. For this randomized phase 2 study ( Identifier: NCT03922308), researchers evaluated the safety and efficacy of rADAMTS13 among patients with iTTP experiencing an acute episode.

The study had 3 arms: a placebo arm (arm 1), a once-daily rADAMTS13 arm (arm 2), and a twice-daily rADAMTS13 arm (arm 3). The study’s primary endpoints were rADAMTS13 pharmacokinetics in patients receiving treatment for an iTTP episode, as well as any relationship between ADAMTS13 levels, biomarkers, and safety.

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Among 28 patients enrolled, 10, 9, and 9 were randomly assigned to arms 1, 2, and 3, respectively; 9, 6, and 8 patients completed therapy. At baseline, patients in arm 3 had lower platelet levels than did patients in arms 1 or 2.

Analysis showed an improvement in median ADAMTS13 plasma activity in arms 2 and 3 compared with arm 1, and further that mean ADAMTS13 activity increased within 24 hours of rADAMTS13 administration.

Adverse event rates were, overall, similar among the 3 arms. There were 6, 2, and 3 serious events that were noted in arms 1, 2, and 3, respectively. No serious treatment-related events or bleeding events were noted in the rADAMTS13 arms. “These data support further investigation of the safety and efficacy of rADAMTS13 in the treatment of patients with iTTP,” the study’s presenter said.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, or device companies. Please see the original reference for a full list of disclosures.


Scully M, Baptista J, Bhattacharya I, et al. Phase 2 randomized, placebo-controlled, double-blind, multicenter study of recombinant ADAMTS13 in patients with immune-mediated thrombotic thrombocytopenic purpura. EHA 2023. June 8-11, 2023. Abstract S305.