The Food and Drug Administration limited eligibility for the Alzheimer’s Disease treatment Aduhelm, an abrupt change in prescribing guidance linked to the sky-high price tag and dubious scientific evidence that it works.

“Treatment with ADUHELM should be initiated in patients with mild cognitive impairment or mild dementia stage of disease. … There are no safety or effectiveness data on initiating treatment at earlier or later stages of the disease than were studied,” the FDA announced Thursday.