Dive Brief:

• The Food and Drug Administration is investigating the safety of a Takeda Pharmaceutical medicine for a rare blood clotting disorder, after the death of a pediatric patient.
• Adzynma won FDA approval in 2023 to treat adults and children with congenital thrombotic thrombocytopenic purpura. The drug is a genetically engineered version of a blood-clotting enzyme that is deficient in these patients, and designed to prevent complications that, left untreated, have a 90% mortality rate. The clearance included both prophylactic and on-demand treatment with the medicine.
• On Friday, the FDA announced it has received reports that patients treated with Adzynma developed antibodies that neutralize these enzymes, and the pediatric patient’s death “appears to be related” to Adzynma. Takeda said there has been no confirmed causal relationship between the death and the company’s medicine.

Dive Insight:

The FDA was concerned enough about the reports to issue a safety communication and is evaluating whether to take further regulatory action. But the agency also said currently available assays can’t distinguish between the neutralizing antibodies that target the lab-created enzyme or those that go after the naturally occurring enzymes.

There were no reports of neutralizing antibodies in the clinical studies Takeda submitted to support approval of its drug, though the prescribing information does contain a warning about the potential risk of developing them. The presence of neutralizing antibodies was identified in the patient who died about 10 months after treatment started, the FDA said.

Takeda learned of the patient death in July and reported it to the FDA while also conducting a “thorough assessment” on its own that found no link to Adzynma. “The health and safety of the patients we serve is our top priority and we are saddened by the death of this patient,” the company said Friday. “There are no changes to the overall risk/benefit profile of Adzynma at this time.”

Patients with concerns about their treatment regimen should speak to their healthcare providers, the company added. Adzynma is not a major seller for Takeda, bringing in 4.8 billion yen, or roughly $32 million, in the first half of the Japan-based company’s current fiscal year.