(HealthDay News) — Two people have now died from brain hemorrhages that may be linked to an experimental drug for Alzheimer’s disease, calling into question the medication’s safety.

A 65-year-old woman with early-stage Alzheimer’s disease recently died from a massive brain bleed that some researchers link to lecanemab, an antibody drug designed to bind to and remove amyloid-beta from the brain, according to a report published Nov. 27 in Science Insider.

The woman suffered a stroke as well as a type of brain swelling and bleeding that has been previously seen with such antibodies, the report noted. Emergency physicians at Northwestern University Medical Center in Chicago treated the woman with a tissue plasminogen activator. She immediately had substantial bleeding throughout her brain’s outer layer.

“As soon as they put it in her, it was like her body was on fire,” her husband told Science Insider. “She was screaming, and it took like eight people to hold her down. It was horrific.” The woman died a few days later, according to the case report.

The death follows that of an 80-year-old man who was taking part in lecanemab’s phase 3 clinical trial. His death was linked to a possible interaction between the experimental drug and the blood thinner apixaban.

Rudolph Castellani, MD, a Northwestern neuropathologist who autopsied the woman, determined that she had amyloid deposits surrounding many of her brain’s blood vessels. The woman had been receiving biweekly infusions of lecanemab, which appears to have inflamed and weakened her blood vessels, Castellani said. These vessels then burst when exposed to a tissue plasminogen activator, something that can happen even in conventional stroke cases.

The Japanese firm Eisai Co. is scheduled this week to provide the first detailed account of lecanemab’s phase 3 trial, which included about 1,800 people with signs of early Alzheimer’s disease. Eisai developed lecanemab with the Swedish firm BioArctic and sponsored the clinical trial with US biotech company Biogen. A news release issued by the company in September said people taking lecanemab had less amyloid and 27% less cognitive decline than people who received a placebo during an 18-month period.

Eisai declined to comment on the woman’s case, Science Insider said. “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.

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