Biogen plans to advance Alzheimer's drug research into late-phase research

Biogen will push a potential Alzheimer's disease treatment into late-stage clinical testing after the drug in early-phase research cleared away a sticky plaque that clogs patients' brains.

The pharmaceutical company said Tuesday that it was still continuing the study, but researchers have seen enough to start moving "aggressively" into late-stage research, which is generally the final phase before a company submits a drug to regulators for approval. Biogen executives cautioned while speaking at a Deutsche Bank conference that the results must be replicated in the bigger and more expensive study.

Nevertheless, Biogen shares jumped after markets opened Tuesday morning.

There is no cure for Alzheimer's disease, the most common form of dementia. About 35 million people worldwide have Alzheimer's, and current treatments only temporarily ease symptoms.

Drugmakers have tried — and failed — for years to develop a treatment. Last summer, another biotech drug developer, Genentech, said its experimental drug failed to slow mental decline in midstage studies on more than 500 people with mild to moderate Alzheimer's disease. But the treatment showed some promise in patients with a milder form of the disease who received a higher dose.

Biogen Idec Inc. executives said Tuesday that their drug focused on patients with early forms of Alzheimer's. The company expects to present the full results from its research at a conference this spring.

Company shares climbed 7 percent, or $21.63, to $330.07 Tuesday morning, while broader indexes rose slightly.