Biogen’s stock jumped 42% in midmorning trading Wednesday after the Food and Drug Administration staff said they have enough data to support approval of the company’s experimental Alzheimer’s drug Aducanumab.

The FDA said it agrees that results from Biogen’s late-stage trial, study 302, are “highly persuasive” and the study is “capable of providing the primary contribution to a demonstration of substantial evidence of effectiveness of aducanumab.”

“Based on the considerations above, the applicant has provided substantial evidence of effectiveness to support approval,” FDA staff said in a document reviewing the drug published on the agency’s website.

The FDA also said the drug has “an acceptable safety profile that would support use in individuals with Alzheimer’s disease.”

The Cambridge, Massachusetts-based company’s drug targets a “sticky” compound in the brain known as beta-amyloid, which is hypothesized to play a role in the devastating disease.

A panel of outside experts is expected to meet Friday to recommend the drug’s approval to the FDA.

Alzheimer’s disease is a progressive neurodegenerative disorder that slowly destroys memory and thinking skills. The Alzheimer’s Association estimates 5.8 million Americans are living with the disease.

There are currently no drugs cleared by the FDA that can reverse the mental decline from Alzheimer’s, which is the sixth leading cause of death in the United States.

The FDA has approved Alzheimer’s drugs aimed at helping symptoms, not actually reversing or slowing the disease itself. Biogen estimates about 1.5 million people with early Alzheimer’s in the United States could be candidates for the drug, according to Reuters.

Analysts were previously skeptical about the drug’s benefits after Biogen reversed its decision to seek regulatory approval.

In March of 2019, Biogen pulled the plug on the Alzheimer’s drug after an analysis from an independent group revealed the medicine was unlikely to work. However, the company shocked investors in October of that year by announcing it was seeking regulatory approval for the drug after all.

Biogen scientists said at the time that a new analysis of a larger data set showed that aducanumab “reduced clinical decline in patients with early Alzheimer’s disease.”

The FDA’s final decision on Biogen’s drug is expected by March.