Breakthrough Alzheimer’s Drug Slows Disease 35%: Study

Scientists believe they may have finally found a long sought-after drug to slow down the progression of Alzheimer’s.

Donanemab, a new drug developed by Indianapolis-based pharma giant Eli Lilly, showed promising results in phase 3 clinical trials. The medication showed the ability to slow the progression of early-stage Alzheimer’s by 35% over 72 weeks, and cleared tau proteins linked to the disease from patients' bloodstream.

Gil Rabinovici, M.D., who leads Alzheimer’s research at the University of California, San Francisco, and was not involved in the study, said in a statement that the research is “just the opening chapter in a new era of molecular therapies for Alzheimer’s disease and related neurodegenerative disorders.” 

There are currently limited options on the market for treating Alzheimer’s. The disease affects 6.7 million Americans over the age of 65, more than 10% of America’s elderly population with most living in the east and southeastern region of the U.S. Its estimated economic burden is nearly $350 billion. It is responsible for 120,000 annual deaths, the seventh leading killer of Americans.

Despite the disease’s prevalence, little is known about how it functions and how to treat it. Previous research has linked the disease to amyloid beta and tau proteins– which naturally form in the brain – are both amino acids found in the brain of patients with Alzheimer’s. These proteins cause plaque to form on the brain which could disrupt and destroy neurons and lead to cognitive decline. However, scientists debate on which protein is most responsible for the disease, or if either is actually the cause.

The lack of clarity surrounding the disease’s origins have made it tough for scientists to develop a medication. However, a new class of monoclonal antibody drugs may be key to a breakthrough.

First came a drug  called aducanumab, a joint venture from biotech and pharmaceutical companies Biogen and Eisai, sold under the name Aduhelm. The treatment received controversial Food and Drug Administration (FDA) approval despite doubts over the drug’s effectiveness in clinical trials. However, the drug was later rejected for coverage by Medicare, effectively killing the medication. Biogen has pulled all marketing for it and has not pursued approval in Europe.

The Cambridge, Massachusetts-based company then came out with Leqembi, which received FDA approval in January. The drug showed the ability to slow the progression of Alzheinmmer’s by an average of 27% in early stage patients – a remarkable feat. However, the death of three patients during clinical trials have fueled concerns surrounding the medication.

Biogen’s falters have opened the door for Eli Lilly, which is hoping to capitalize on the market with donanemab.

The company recruited 1,736 participants for phase 3 clinical trials, published Monday in the Journal of the American Medical Association. Each was a patient diagnosed with a case of symptomatic Alzheimer’s. Study participants received either a dose of the drug or a placebo every four weeks for 72 weeks. 

At the end of the study, those who received donanemab saw their cognitive decline slow, and had lower levels of tau protein in their bloodstream.

However, the drug did not lower tau levels in the brain, where the protein is believed to be the most dangerous. Its benefits were also only seen in patients in the early stages of the disease, with later stage patients not seeing results.

Eli Lilly is expected to apply for FDA approval for donanemab. If successful, the drug could prove to be another emerging blockbuster for the company. The pharmaceutical company is currently seeking FDA approval for its type 2 diabetes medication Mounjaro as a weight loss drug, and has the promising retatruride in its pipeline as well.

The company earned $28.5 billion in revenue in 2022. The firm expects to eclipse $30 billion this year.