WASHINGTON (AP) A much-debated drug for Lou Gehrigs disease won U.S. approval Thursday, a long-sought victory for patients that is likely to renew questions about the scientific rigor behind government reviews of experimental medicines.

The Food and Drug Administration approved the drug from Amylyx Pharmaceuticals based on results from one small, mid-stage study in which patients with the debilitating disease appeared to progress more slowly and survive several months longer. Typically, the FDA requires two large studies or one study with very persuasive survival results for approval.