Alzheimer's blood test from Roche, Eli Lilly nabs FDA breakthrough tag

After more than a year in the works, Roche and Eli Lilly have taken a step closer to delivering their blood test designed to aid in the diagnosis of earlier cases of Alzheimer’s disease.

The FDA has granted their work a breakthrough designation to help accelerate its development. Roche’s Elecsys plasma assay searches for and quantifies phosphorylated fragments of the brain protein tau, known as pTau-217, with the goal of capturing a biomarker that can distinguish Alzheimer’s from other neurodegenerative disorders.

According to the company, a patient’s positive result would correlate with a high likelihood of finding Alzheimer’s characteristic amyloid plaques through a PET scan or an analysis of their cerebrospinal fluid while a negative finding would help to rule the possibility out.

The two companies first announced their diagnostic collaboration in March 2023. At the same time, Eli Lilly has been pursuing the FDA’s blessing for its Alzheimer’s antibody donanemab—a journey that hit a roadblock last month after the agency announced it planned to convene an independent advisory committee to evaluate the drug.

Last month also saw the FDA publish new guidance on how it may approach the review of Alzheimer’s therapy hopefuls. The draft document said measures of amyloid reduction could serve as a surrogate in clinical trials as a predictor of a drug’s possible benefits but did not say that it could serve as a study’s primary endpoint alone.

With Roche’s help, Eli Lilly said it believes the pTau217 blood test could one day help identify patients eligible for Alzheimer’s clinical trials or direct them to approved therapies for the condition.

“The development of the Elecsys pTau217 plasma assay is another milestone in our collaboration with Roche Diagnostics that will advance the Alzheimer’s diagnostic ecosystem,” Lilly Neuroscience President Anne White said in a statement

Roche Diagnostics CEO Matt Sause, meanwhile, has estimated that 75% of dementia cases worldwide remain undiagnosed—a raw number that could grow to 140 million people by 2050—and that pTau217 levels will become an essential clinical identifier.

“Consequently, there is a critical role for diagnostics to play in addressing this global health challenge,” Sause said. “We plan to leverage our installed base of diagnostic systems, which is the largest in the world, to ensure we are able to create access to this test for those who need it the most.”

Roche previously earned an FDA breakthrough tag for a separate Alzheimer’s-focused blood test—aimed at the proteins pTau-181 and apolipoprotein e4, or ApoE4—and has secured agency approvals for two pairs of Elecsys in vitro diagnostics that analyze CSF for amyloid and tau.