(Reuters) -Amylyx Pharmaceuticals said on Wednesday it will stop development of its experimental drug for a rare brain disorder after it failed to improve symptoms in patients during a mid-stage trial.

Shares of the company fell 1.7% in premarket trading after the drug, AMX0035, showed no benefit over a placebo at 24 weeks in patients with a rare and fatal brain disorder called progressive supranuclear palsy (PSP).

AMX0035 was approved by the Food and Drug Administration to treat amyotrophic lateral sclerosis in 2022 and was sold under the brand Relyvrio in the U.S. But the company voluntarily withdrew the drug from the U.S. and Canada last year after failing in a key late-stage trial.

“While a slight disappointment, we believe investors had very low expectations for the data,” TD Cowen

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