Alzheimer’s has long been a scourge for tens of millions of people, robbing them gradually of their memory and cognition, and launching an agonizing decline for their loved ones to watch. It has also stubbornly eluded treatment for decades.
But a glimmer of hope emerged Friday from Cambridge biotech Biogen Idec Inc., which said early-stage study results showed an experimental drug slowed the mental decline of a small number of patients who had early indications and mild cases of the neurodegenerative disorder.
“We hope they’re successful,” said Jim Wessler, president of the Alzheimer’s Association of Massachusetts and New Hampshire. “If some of these drugs can make it through clinical trials, they can have massive health benefits for millions of patients and their families.”
Biogen’s clinical data looks “extremely positive,” demonstrating a sharper drop in patients’ loss of cognitive functions than has been seen in other experimental treatments, said Dr. Thomas Wisniewski, neurology professor at New York University, who specializes in Alzheimer’s. Many previous drug candidates that initially looked promising have ultimately failed.
“It’s a long time since there’s been positive results like this in a clinical trial for Alzheimer’s disease,” Wisniewski said.
Dr. Mark W. Albers, a neurologist at Massachusetts General Hospital, also called the clinical results encouraging. “It’s an early-stage trial with a small number of patients, so you have to approach it with caution,” he said, suggesting the next round of testing will be telling. “If these results are confirmed, it will be a significant breakthrough.”
Analysts said the findings exceeded their expectations. But they also noted the study was designed to focus on those with the mildest forms of the disease. Before the company can apply for regulatory approval to sell the drug commercially — a milestone that could still be several years away — the therapy will have to be tested on a much larger and more diverse global patient population.
Still, even the tiniest sign of progress against a disease that has proven so difficult to treat caused excitement in the life sciences world.
The drug’s effect on patients in Biogen’s ongoing US trial has been “well above our threshold for significance,” Geoffrey C. Porges, senior analyst at financial firm Sanford C. Bernstein & Co., wrote in a note to investors.
Biogen said its testing produced “statistically significant” evidence the drug slowed the cognitive decline of certain patients and reduced amyloid plaque in the brain, which is thought to play a pivotal role in the development of Alzheimer’s symptoms.
Breaking up the brain-ravaging plaque has been seen by scientists as the key to attacking Alzheimer’s. But several previous drug candidates have failed to prove that approach valid.
Biogen Idec chief medical officer Al Sandrock said the company’s new data “goes a long way toward confirming the amyloid hypothesis.”
“We’re very encouraged that we could have something that could help patients,” Sandrock said. “We neurologists have been dreaming about having a disease-modifying treatment for Alzheimer’s for a long time.”
Sandrock said Biogen will use the results of the early-stage study to find a dosage of the experimental drug that provides the most benefit for the least risk to patients in later trials.
Based on the findings, Biogen said it plans to advance the drug compound called aducanumab to late-stage clinical trials and would begin to enroll patients later this year. The Food and Drug Administration, which approves new medicines, must OK the design and scope of the new trial.
Investors reacted strongly to the news Friday. Shares of Biogen Idec shot up $42.33 to $475.98 a share Friday, a gain of about 10 percent. The company’s shares have climbed nearly 50 percent since it previewed its findings in early December.
Alzheimer’s organizations estimate that more than 5 million Americans and more than 25 million people worldwide have the progressive neurological disorder. The number of patients is projected to triple in the United States by 2050 as members of the baby boom generation grow older. While some existing drugs are prescribed to treat Alzheimer’s symptoms, there are no available therapies that actually modify the disease.
“It’s expensive, it’s taxing, and it’s a terminal disease that right now has no treatments,” Wessler said.
Biogen’s experimental drug has been tested on 166 patients experiencing the first phases of Alzheimer’s since the study was launched in 2012. Using imaging scans, patients were assessed on rating scales measuring their mental states and clinical dementia.
The patients were randomly divided into five groups. One group was given placebos while the four others received different doses of aducanumab. The study was designed to gauge the drug’s safety and tolerability but, to the surprise of some involved in the program, it also proved effective when given in certain doses and for certain periods in slowing clinical decline and reducing amyloid plaque.
Biogen licensed the aducanumab compound, a monoclonal antibody, from Swiss drug maker Neurimmune AG in 2007 and has shepherded it through early development into clinical trials.
The company presented its study results Friday at the International Conference on Alzheimer’s and Parkinson’s Diseases and Related Neurological Disorders in France. A large group of US-based doctors, scientists, and stock analysts flew across the Atlantic for the presentation, underscoring the intense interest in Biogen’s experimental drug.
Some researchers in the audience were “quite ecstatic,” Wisniewski said.
At the same time, he pointed to some troubling caveats. For instance, about a quarter of the patients given higher doses of the drug had to discontinue treatment after developing complications such as swelling that appeared to be related to fluid buildup in the brain.
Still, he said, Biogen’s drug appears to be “in a completely different league” from another experimental drug being tested by Indianapolis drug maker Eli Lilly & Co.
Biogen, a leader in multiple sclerosis medicines, is not the only company working to tackle Alzheimer’s. Dozens of compounds, using a range of therapeutic approaches, are being tested in research labs as potential treatments, the vast majority in preclinical stages. Drug giants Eli Lilly and Merck & Co., among others, have Alzheimer’s therapies under clinical development.
And at Friday’s medical conference in France, a smaller Massachusetts company, Alzheon Inc. of Lexington, reported its own promising data from an early-stage trial of an experimental pill to inhibit formation of amyloid clumps.Robert Weisman can be reached at email@example.com. Follow him on Twitter @GlobeRobW.