Positive research suggests that an Alzheimer’s drug can delay cognitive deterioration.

The drug Lecanemab, developed by Eisai and Biogen Inc., slowed the rate of cognitive decline by 27% in patients in the early stages of the disease in a phase III clinical trial, with results published Tuesday in the New England Journal of Medicine. This makes it the first drug of its kind to produce such positive trial results.

“Lecanemab reduced markers of amyloid in early Alzheimer’s disease and resulted in less decline than placebo on all measures of cognition and function at 18 months,” said Dr. Christopher Van Dyck, director of the Yale Alzheimer’s Disease Research Center, during his presentation of trial efficacy results at the Clinical Trials on Alzheimer’s Disease meeting, held in San Francisco.

The drug “resulted in moderately less decline on measures of cognition and function,” compared to patients who received a placebo, according to research conducted on nearly 1,800 patients over the course of 18 months.

Lecanemab’s efficacy and safety in the early stages of Alzheimer’s disease, the companies said, “require longer trials.”

Two proteins—amyloid-beta and tau—build up in the brains of people with Alzheimer’s disease. They aggregate and form plaques, impairing cell function and resulting in symptoms like confusion and memory loss.

A monoclonal antibody called lecanemab aids in clearing the amyloid-beta clumps.

Participants in the trial were divided into two groups, each of which had an initial Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) score of about 3.2. This score, which measures dementia impairment, has a scale from 0 indicating no impairment to 18.0 indicating severe impairment. A score of 3.2 indicates very mild impairment.

Patients in the Lecanemab group saw an increase in their score of 1.21 points over the course of 18 months, while those in the placebo group saw an increase of 1.66 points.

Although most side effects were asymptomatic, there were a few negative events in the trial, according to the companies, including 20% of Lecanemab-treated patients who experienced brain swelling or brain bleeding.

Two patients who had brain hemorrhages died after the 18-month study. However, Eisai claimed that no fatalities are thought to be related to Lecanemab.

The Barrow Neurological Institute’s Dr. Marwan Sabbah, a neurologist, stated during the presentation on Tuesday that physicians should exercise caution when deciding whether or not to recommend the medication for patients who are taking blood thinners.

The news “encouraged” the Alzheimer’s Association, which urged the US Food and Drug Administration to expedite Lecanemab’s approval. Currently, the FDA is expected to decide on an approval by January 6, 2023.

If approved, the medication would probably only be prescribed to people with very mild cognitive impairment and very early-stage patients of the disease.

The Alzheimer’s Association said in a statement that these peer-reviewed, published results “show Lecanemab will provide patients more time to participate in daily life and live independently.” It might take many more months for them to recognize their spouse, kids, and grandchildren.

“Treatments that deliver tangible benefits to those with mild cognitive impairment (MCI) due to Alzheimer’s and early Alzheimer’s dementia are as valuable as treatments that prolong the lives of those with other terminal diseases,” the statement continued.

The findings were encouraging, according to researchers who were not involved in the study, such as Dr. Leah Croll, a neurologist and assistant professor of neurology at Temple University’s Lewis Katz School of Medicine.

Given the numerous setbacks the Alzheimer’s drug pipeline has experienced over the years, she told ABC News that this was encouraging news for the millions of Americans affected by the disease.

Over the years, there have been countless drug trials for Alzheimer’s, the majority of which have yielded negative results.

Lecanemab is a significant step forward in the way we manage Alzheimer’s, according to Croll. I have faith that we will eventually have even more options to offer patients as we start to make progress against this disease process.

The drug’s price may be a problem if it receives FDA approval. For instance, aducanumab, a contentious Alzheimer’s medication that received approval last year despite detractors’ claims that the trial data was inconclusive, costs about $28,000 annually.