The safety risks have fueled debate among doctors about whether Leqembi is a net-positive for patients. Some see it as the most effective option yet for slowing a devastating disease, while others believe it offers marginal benefits at best.

According to Constantine Lyketsos, director of the Memory and Alzheimer’s Treatment Center at Johns Hopkins Medicine, Leqembi is “doing better than the placebo, but not much better.”

In an interview earlier this year, Lyketsos argued there appears to be a ceiling of effectiveness for even the more promising anti-amyloid drugs. Because of those limits, and the potential side effects, he said he is “certainly going to be very conservative at first” when prescribing medicines like Leqembi.

Costs may also be a concern for prescribers and patients. Medicare expects members on its original plan to pay 20% coinsurance of the Medicare-approved cost for Leqembi once they meet their Part B deductible. That could leave some patients on the hook for hundreds or thousands of dollars.

Medicare noted in a statement that costs may differ depending on whether patients have supplemental coverage or secondary insurance, or if they’re enrolled in a Medicare Advantage plan.

“With FDA’s decision, [the Centers for Medicare and Medicaid Services] will cover this medication broadly while continuing to gather data that will help us understand how the drug works,” said CMS Administrator Chiquita Brooks-LaSure.