Biogen Inc’s experimental Alzheimer’s disease drug was found effective enough in a large trial to support approval, U.S. Food and Drug Administration staff said on Wednesday, potentially making it the first drug to be approved in decades to slow down the progress of the memory robbing disease.

The FDA staff’s comments that come ahead of a meeting of a panel of independent advisers to the health regulator on Friday sent shares of the company soaring 30%.

Cambridge, Massachusetts-based Biogen in October last year revived its plans to seek approval for the drug, months after it had said that a “futility analysis” from two studies of the drug showed it was unlikely to pass the trials.

Biogen said it changed plans after a new analysis of the two studies showed a high dose of the drug could slow the disease’s progression.

Some Wall Street analysts remain skeptical of the drug, as one of those two studies failed its main goal.

The FDA staff said one of the two studies “provides the primary evidence of effectiveness as a robust and exceptionally persuasive study demonstrating a treatment effect on a clinically meaningful endpoint.”

A final decision on the drug, jointly developed with Japan’s Eisai Co Ltd, is due by March 2021.

Reuters