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Glimmer of a Silver Lining in Latest Alzheimer's Trial

Brain challenge. Researchers have struggled to develop drugs for treating Alzheimer’s disease.

National Institutes of Health

Earlier this summer, Alzheimer's researchers got disappointing—but not entirely unexpected—news from a phase III clinical trial of bapineuzumab, an antibody that targets β amyloid, the protein fragment that forms pathological clumps in the brains of patients. Bapineuzumab failed to improve cognition in two large trials of patients with mild to moderate Alzheimer’s disease. Today, Eli Lilly and Company announced slightly more encouraging results from another closely watched trial, for an anti-amyloid antibody called solanezumab.

First the bad news: Solanezumab failed to slow cognitive decline in two trials with more than 2000 people with mild to moderate Alzheimer’s disease. However, the company says in a statement, a secondary analysis of data from the mild Alzheimer's patients enrolled in both trials indicated that the drug did slow cognitive decline in this subgroup. A similar analysis of the moderate Alzheimer’s patients in both trials showed no effect. Lilly says its plans for solanezumab are still undecided, pending discussions with regulators, but it will continue an open-label extension study in which patients from the two recently completed trials can continue to take the drug.

"We see hopeful and encouraging information here," says Maria Carrillo, senior director of medical and scientific relations for the Alzheimer's Association. So far, Lilly has released only preliminary findings, but Carrillo says they appear to be the best evidence yet that anti-amyloid therapy can slow cognitive decline in some patients.

Pharmaceutical companies have invested heavily in anti-amyloid therapies, with largely disappointing results in clinical trials. But many researchers now believe these trials have failed because the drugs were given to patients whose disease was already too advanced. In recent years, it has become clear that amyloid begins accumulating in the brain decades before memory loss and other symptoms appear. Intervening at earlier stages of the disease may be a better strategy. Three clinical trials expected to begin next year will test this idea by giving anti-amyloid therapies to people who are at risk of Alzheimer’s but have yet to develop symptoms.