A second study participant has died possibly as a result of the experimental antibody drug, lecanemab, meant to treat Alzheimer's, Science reported Nov. 27.
The 65-year-old woman died from a massive brain hemorrhage after suffering a stroke. The autopsy showed the woman, like the other participant who died during the trial, had amyloid deposits surrounding many of her brain's blood vessels. The pre-existing condition, found in both Alzheimer's patients, often goes undetected and likely contributed to her hemorrhage after biweekly infusions of lecanemab inflamed and weakened the blood vessels, according to the report.
Blood thinners, which were administered to the participant to treat her stroke, may have also played a role in her death, according to researchers.
"It was a one-two punch," Rudolph Castellani, a Northwestern neuropathologist who studies Alzheimer's and conducted an autopsy at the request of the patient's husband, told Science. "There's zero doubt in my mind that this is a treatment-caused illness and death. If the patient hadn't been on lecanemab she would be alive today."
The case was allegedly shared with Eisai, the Japanese company that originally developed lecanemab with the Swedish firm BioArctic, and sponsored the trial with U.S. biotech partner Biogen.
"All the available safety information indicates that lecanemab therapy is not associated with an increased risk of death overall or from any specific cause," the company said in a statement to Science. Eisai declined to comment on the woman's particular case.