The US Food and Drug Administration has not approved a new drug to treat Alzheimer’s disease since 2003. In an effort to end that drought, Eli Lilly, an Indianapolis-based pharmaceutical company, has developed a drug called donanemab, an antibody designed to clear deposits of amyloid-β peptides that form plaques in the brains of patients with AD. At the International Conference on Alzheimer’s and Parkinson's Diseases, held virtually March 9–14, researchers from Lilly announced Phase 2 trial results that donanemab slowed the progression of the disease. The study was published Saturday (March 13) in the New England Journal of Medicine during the team’s presentation.
The study followed 257 patients with early stages of AD over the course of 76 weeks. The primary endpoint of the study was measured by scores on the integrated Alzheimer’s Disease Rating Scale (iADRS). The score is based on two common systems used to determine function in AD patients, namely, completing cognitive tasks, such as recalling a list of words or naming objects, and performing daily activities such as getting dressed or dialing a phone.
The researchers report that the differences of iADRS scores between the placebo and experimental groups were apparent 36 weeks in, and by the end of 76 weeks, the decline among those taking the drug was 32 percent lower than among those given the placebo. Starting on average at 106 out of 141 points on the scale, those taking the drug still dropped close to seven points on the scale, while those given the placebo fell a little more than 10 points.
“Out of 18 months, in comparison to the people that did not get the drug, these folks were declining six months slower,” Maria Carrillo, the chief science officer of the Alzheimer’s Association who was not involved in the work, tells CNN. “That’s six more months of better cognition, better memories, better enjoyable times with your family.”
“Donanemab has the potential to become a very important treatment for Alzheimer’s disease. We were pleased to see not only slowing of cognitive and functional decline, but also very substantial clearance of amyloid plaques and slowing of spread of tau pathology,” Lilly’s Chief Scientific Officer, Daniel Skovronsky, says in a press release. “The constellation of clinical and biomarker results indicates the potential for long-term disease modification.”
Although those secondary endpoints—a clearance of amyloid plaques and a slowing of tau pathology—improved in patients taking the drug, the changes were not statistically significantly different from the placebo group. As such, not everyone is convinced that the results from the primary endpoint will allow the drug to move forward. The Motley Fool, an investment advisor website, notes that the FDA hasn’t reviewed potential new drugs on iADRS scores alone.