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.”

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