In a shocking reversal, Biogen on Tuesday said that it would resurrect an Alzheimer’s drug that the company previously said had failed and will ask the Food and Drug Administration to approve it.

The company said a “new analysis of a larger dataset” showed that the drug, aducanumab, reduced clinical decline in patients with early Alzheimer’s disease on multiple measures of the drug’s effectiveness. That directly contradicts a decision in March to halt studies of the therapy based on the recommendations of an independent monitoring board that was charged with protecting patients in the study.