Biogen Inc has laid out more data on its experimental Alzheimer’s drug that raised no major safety alarms but also offered little compelling evidence the drug, once declared a failure, actually works.

Experts had been watching closely for any statistical abnormalities or excess safety issues that would affect how the drug is reviewed by the US Food and Drug Administration (FDA).

If approved, aducanumab would be the first treatment designed to delay progression of the fatal, mind-robbing disease for millions of patients.

Biogen’s fairly neutral showing and supportive comments from a panel of experts chosen by the company buoyed investor hopes that the treatment has a reasonable shot at approval.

Shares in the company rose more than 3%.

The reaction from other scientists attending the meeting, however, was more mixed, with some suggesting the company should do another trial.

“It was a well-curated presentation. Biogen made the argument that response to the therapy was related to cumulative dose how much drug was received over the course of the study,” said Dr. Adam Boxer, head of the clinical trials program at the University of California, San Francisco’s memory and aging center.

“I would have liked to see more data to be convinced.”

Biogen had scrapped development of the drug in March, then reversed course in October, saying a more detailed analysis showed some patients with very early forms of the disease benefited from taking higher doses over an extended period of time.

The company has said it plans to file for US approval of the drug early next year.

For decades, companies have tried and failed to crack the code of Alzheimer’s.

It has been 16 years since the FDA last reviewed an application for a new treatment and the need for an effective a drug is dire. Wall Street analysts estimate aducanumab could reap $4 billion in annual sales within a few years of approval.

According to the US Centers for Disease Control and Prevention, the number of people in the United States living with Alzheimer’s is expected to triple to 13.8 million by 2050.

Alzheimer’s experts on a panel organized by Biogen, expressed confidence the complicated aducanumab studies showed that the drug was able to slow progression of the disease.