This Dec. 10, 2020 file photo shows Food and Drug Administration building in Silver Spring, Md. (Photo: AP)

The U.S. Food and Drug Administration (FDA) approved Aduhelm (aducanumab) on Monday for the treatment of Alzheimer's, the first new medicine against the disease in almost two decades and the first to address cognitive decline linked to the condition.

Aduhelm was approved using the accelerated approval pathway, which can be used for a drug for a serious or life-threatening illness that provides a meaningful therapeutic advantage over existing treatments, according to the FDA.

"Aduhelm is the first treatment directed at the underlying pathophysiology of Alzheimer's disease, the presence of amyloid beta plaques in the brain," said FDA's Patrizia Cavazzoni.