As reported on BioSpace, the U.S. Food and Drug Administration (FDA) has launched an investigation into reports of serious adverse events, including one fatality, associated with Takeda’s enzyme replacement therapy Adzynma. The therapy is approved for treating congenital thrombotic thrombocytopenic purpura (cTTP), a rare genetic blood-clotting disorder caused by mutations in the ADAMTS13 protein.
According to the FDA, several patients developed neutralizing antibodies against the protein targeted by Adzynma. The reported death occurred in a pediatric patient approximately 10 months after starting treatment. The child exhibited progressive neurological symptoms and was found to have anti-ADAMTS13 antibodies. The agency believes the reaction may be linked to enzyme replacement therapy, as the patient had previously experienced severe allergic responses to fresh frozen plasma, another standard treatment for cTTP.
The FDA emphasized that current testing cannot distinguish whether these antibodies target the replacement enzyme or the body’s own protein. Importantly, such immune responses were not observed during clinical trials and have only been reported in post-marketing use.
cTTP affects fewer than one in a thousand individuals and often manifests in infancy or early childhood. Adzynma, approved in 2023, is the first preventive enzyme replacement therapy for this condition, though it can also be administered during acute episodes.
The FDA continues to monitor the situation and advises healthcare providers to remain vigilant for signs of antibody development in patients receiving Adzynma.
