For the first time in almost 20 years, the Food and Drug Administration approved a new drug this month to treat Alzheimer’s disease. The approval of Aduhelm, made by the Cambridge-based Biogen, had been previously voted against by the FDA advisory committee, and has been wildly controversial.

Three doctors who sit on the advisory committee have resigned, including Dr. Aaron Kesselheim, a professor of medicine at Harvard Medical School, who joined Aaron Schachter on Morning Edition to explain his decision and his concerns around the FDA approval process.

“There's no good evidence that the drug works,” Kesselheim said. “The decision itself was so inexcusable for so many different ways … I would love to be able to give them [patients with Alzheimer’s] a new medication that provides them with reasonable hope, but that's not this drug.”

Kesselheim said the drug itself is dangerous, and cited clinical data that showed about one third of patients receiving the drug having evidence of brain swelling or hemorrhage. He said that in about 10% of patients, the side effects were severe enough to require additional MRIs and monitoring.

Aduhelm is a monoclonal antibody that targets amyloid plaques, the main marker for Alzheimer’s disease in the brain, but Kesselheim said studies have shown that reducing amyloid plaques doesn’t necessarily change the course of the disease. Plus, he said, the drug was tested on patients in the early phase of the disease, yet the FDA approved it for all stages.

“I think people have a lot to lose by taking this drug,” he said, noting that in addition to requiring continued monitoring and its negative side effects, the drug is extremely expensive, potentially costing more than $50,000 a year. “Both bodily toxicity and financial toxicities [are things] that people need to be worried about.”

"I would love to be able to give them [patients with Alzheimer's] a new medication that provides them with reasonable hope, but that's not this drug."
-Dr. Aaron Kesselheim

Kesselheim is also calling for more transparency about how the decision was made behind the scenes, and why the approval process shifted over the past year.

“We need to know what the basis was for the FDA's decision and why the FDA changed the course of the decision-making so drastically from the discussion back in November at the advisory committees to the approval today,” Kesselheim said.

And, as the country begins to re-emerge from the pandemic, Kesselheim says trust in medical institutions has been more important than ever.

“The advisory committee was pretty unanimous in its assessment of this drug,” he said. “And so for the FDA to go against the advisory committee and to go against the impressions of many physicians in the field — I think this does threaten to undermine the FDA at a time when trust in the FDA with respect to COVID vaccines is just so important.”