Susan Aaron was an active 74-year-old retiree with Alzheimer’s who was told she might experience extreme fatigue and terrible headaches if she tried a new drug from Eisai Co. that promised to slow the progression of her disease. It didn’t sound like a dealbreaker, so she decided to try it.

Two weeks after her third dose, Aaron was dead.

She died last July after experiencing “severe” brain swelling and bleeding — known side effects of the drug — according to a report to the U.S. Food and Drug Administration. Aaron’s pre-treatment genetic testing showed she was at a heightened risk of such side effects. Her long-term companion, Valerie Porter, who attended her medical appointments and recounted the last few weeks of her life, said Aaron wasn’t properly warned this could happen.