Experimental Alzheimer's drug slows cognitive decline

A small, early-stage trial of an experimental Alzheimer’s drug significantly slowed down the cognitive decline associated with mild to moderate forms of the disease, the drug maker announced on Friday. It was the first time a drug has appeared to successfully combat Alzheimer’s, reigniting hopes for a treatment.

The drug, called aducanumab, is made by Biogen Idec, a Cambridge, Massachusetts-based biotechnology company. It works by blocking the production of amyloid plaques in the brain. People with Alzheimer’s tend to form more of these proteins between the brain’s nerve cells than people without the disease, and scientists have theorized that decreasing the plaques would slow the disease's progression.

The results, which Biogen Idec presented Friday at an international conference on Alzheimer’s and Parkinson’s diseases in Nice, France, marked the first time that an experimental Alzheimer’s drug has shown both a statistically significant reduction of amyloid plaque and a statistically significant slowing of cognitive impairments associated with the disease, according to Alfred Sandrock, the company’s chief medical officer.

He said in a statement that the company planned to move forward with a larger-scale clinical trial later this year.

"It's a bigger treatment effect than we had hoped for," Sandrock said.

Other pharmaceutical companies, including Pfizer and Eli Lilly, have launched expensive trials of Alzheimer’s treatments that failed. And aducanumab still faces years of testing and would not reach the market much before 2020 — and that's if all goes well, analysts told Reuters.

“While still very early, these data are more impressive than anything we’ve seen in [Alzheimer’s disease], justifying the pre-data excitement,” Christopher Raymond, a Robert W. Baird analyst, wrote in a research note.

The trial involved 166 patients, some of whom received varying doses of the drug for 54 weeks and others who received a placebo. By the midpoint of the trial, patients who received small, medium and large doses of aducanumab had a “statistically significant” reduction of amyloid plaques when their brains were measured in a PET scan. The reduction of plaques was even more significant by the end of the trial.

The trial also measured patients’ cognitive functioning using two different questionnaires. While the placebo groups' scores worsened by an average of 3.14 points within a year on one test and an average of 2.04 points on another, those patients taking the highest dose of the drug only declined by an average of 0.58 and 0.59 points, respectively. The slowing of cognitive decline was still statistically significant among the patients who were given a small dose of the drug.

Biogen Idec said aducanumab showed “acceptable safety” for patients in the trial — though some 22 percent of the patients who received the drug got headaches, as opposed to just 5 percent of those who took the placebo.

Alzheimer's disease, the most common form of dementia, leads to progressive memory loss that ultimately results in a person having difficulty functioning independently. The U.S. Centers for Disease Control and Prevention estimates that about 5 million Americans have the disease, but that number is expected to nearly triple to 14 million by 2050.

A successful Alzheimer’s treatment could save the U.S. $220 billion within the first five years after it is introduced, according to the national Alzheimer’s Association.

With Reuters