An experimental drug for Alzheimer’s disease sharply slowed the decline in mental function in a small clinical trial, researchers reported Friday, reviving hopes for an approach to therapy that until now has experienced repeated failures.
The drug, being developed by Biogen Idec, could achieve sales of billions of dollars a year if the results from the small trial are replicated in larger trials that Biogen said it hoped to begin this year. Experts say that there are no really good drugs now to treat Alzheimer’s.
Biogen employs about 1,300 people in the Triangle, where it makes a number of its drugs.
Biogen’s stock had risen about 40 percent since early December, when the company first announced that the drug had slowed cognitive decline in the trial, without saying by how much. Analysts and investors had been eagerly awaiting the detailed results, which were presented Friday at a neurology meeting in France.
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The drug, called aducanumab, appears to have met or exceeded Wall Street expectations in terms of how much the highest dose slowed cognitive decline. However, there was a high incidence of a particular side effect that might make it difficult to use the highest dose.
The company’s stock rose 10 percent, or $42.33, to close Friday at $475.98.
Alzheimer’s specialists were impressed, but they cautioned that it is difficult to read much from a small early-stage, or Phase 1, trial that was designed to look at safety, not the effect on cognition. Also, other Alzheimer’s drugs that had looked promising in early studies ended up not working in larger trials.
“It’s certainly encouraging,” said Dr. Samuel Gandy, director of the Center for Cognitive Health at Mount Sinai Hospital in New York, who was not involved in the study. He said the effect of the highest dose was “pretty impressive.”
Aducanumab, which until now has been called BIIB037, is designed to get rid of amyloid plaque in the brain, which is widely believed to be a cause of the dementia in Alzheimer’s disease. However, other drugs designed to prevent or eliminate plaque have failed in large clinical trials, raising questions about what role the plaque really plays.
Johnson & Johnson and Pfizer abandoned a drug they were jointly developing after it showed virtually no effect in large trials. Eli Lilly and Roche are continuing to test their respective drugs despite initial failures. Experts say there is some suggestion the drugs might work if used early enough, when the disease is still mild.
Biogen tried to increase its chances of success by treating patients with either mild disease or so-called prodromal disease, an even earlier stage.
It also enrolled only patients shown to have plaque in their brains using a new imaging technique. In some trials of other drugs, some of the patients turned out not to have plaque, which could have been one reason the trials were not successful.