(Bloomberg) — Biogen Idec Inc. shares rose after the company said its Alzheimer’s drug showed promising early results and will be quickly moved into a final-stage trial.

In a small, early stage trial, Biogen’s drug BIIB037 reduced beta amyloid in the brain, said Doug Williams, executive vice president of research and development, at a Deutsche Bank conference in Boston today. Beta amyloid, a protein fragment that creates plaque tangles in the brain, is thought to be a key component in Alzheimer’s disease.

The biotechnology company will now push rapidly ahead into an area where other drugmakers have tried and failed. Eli Lilly & Co.’s drug solanezumab, and bapineuzumab — a drug developed jointly by Pfizer Inc., Johnson & Johnson and Elan Corp. — also target amyloid plaques. Both medicines failed to show a significant effect on the disease in final-stage tests on thousands of patients. Lilly is currently retesting solanezumab in earlier-stage patients, while bapineuzumab has been scrapped.

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Alzheimer’s is the most common form of dementia, affecting more than 5 million Americans, according to the Alzheimer’s Association. The disease, which is progressive, causes symptoms including memory loss, confusion, and behavior changes. There is no approved cure for Alzheimer’s.

Biogen, based in Cambridge, Massachusetts, gained 8.6 percent to $333.19 at 9:31 a.m. in New York, the biggest intraday rise since July.

Cognition improvement

Biogen’s drug improved cognition in patients with early signs of the disease 54 weeks after starting treatment, Williams said. The results were pulled from an interim analysis of about 200 patients in the Phase 1 trial, according to the company. Biogen will present full results of the trial at a medical meeting next year, which the company hasn’t named, Williams said.

Biogen didn’t give details on when the final-stage trial would start.

Biogen bought BIIB037, or aducanumab, from Neurimmune Therapeutics in 2007. Biogen has a deal to develop and commercialize the molecule with Japanese drugmaker Eisai Co.

–With assistance from Drew Armstrong in New York.

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