Takeda Pharmaceuticals' Drug Adzynma Under FDA Investigation Related to Patient Death

By Katherine Hamilton

Takeda Pharmaceuticals' drug Adzynma is being investigated by the U.S. Food and Drug Administration due to a death following treatment.

The FDA said Friday it has received reports of neutralizing antibodies to ADAMTS13, including one death, in patients with the blood disorder who were treated with Adzynma.

Adzynma is indicated for prophylactic or on-demand enzyme replacement therapy in patients with the blood clot disorder congenital thrombotic thrombocytopenic purpura (cTTP). ADAMTS13 is an enzyme that is essential for regulating blood clotting, and neutralizing antibodies to it can cause cTTP.

The reported death in a pediatric patient with cTTP appears to be related to Adzynma, the FDA said. The presence of neutralizing antibodies to ADAMTS13 was identified about 10 months after the patient started prophylactic treatment with Adzynma.

Current assays are unable to distinguish neutralizing antibodies to recombinant ADAMTS13 from neutralizing antibodies to endogenous ADAMTS13, the FDA noted.

Adzynma includes information on the potential risk of developing neutralizing antibodies following treatment. Neutralizing antibodies were not reported in cTTP clinical trials, and current labeling doesn't include information about postmarketing reports of neutralizing antibodies, the FDA said.

The FDA is investigating the risk of developing the antibodies with serious or fatal outcomes following treatment with Adzynma, and will evaluate the need for further regulatory action.

Write to Katherine Hamilton at katherine.hamilton@wsj.com

(END) Dow Jones Newswires

November 21, 2025 12:38 ET (17:38 GMT)