Details of failed studies cast pall on Novo Nordisk's GLP-1 as Alzheimer's treatment

By Deena Beasley and Julie Steenhuysen

SAN DIEGO, Dec 3 (Reuters) - Details from two large trials of Novo Nordisk's NOVOb.CO GLP-1 drug semaglutide showed it provided no cognitive benefit for people with early Alzheimer's disease, researchers said at a medical meeting on Wednesday, dashing remaining hopes that the widely used medication could help such patients.

The Danish drugmaker said last week that the trials, which were designed to show that its semaglutide pill Rybelsus could slow progression of the brain-wasting disease by at least 20%, did not meet their goals.

The joint studies showed some improvement in a few key biological measures of the disease, but the changes were small and not enough to make a difference in delaying cognitive decline.

Both trials showed that Rybelsus had no impact at all on the rate of decline in a clinical dementia score compared to a placebo after two years, according to results presented at the Clinical Trials in Alzheimer's Disease meeting in San Diego.

"I don't see that it affects anything that is likely to affect Alzheimer's disease," said Dr. Mary Sano, a Mount Sinai Alzheimer's researcher and a key investigator on the studies.

Alzheimer's, which gradually destroys memory and thinking skills, is characterized by changes in the brain including buildup of amyloid beta plaques and tau tangles that result in loss of neurons responsible for transmitting information.

Novo's trials, which involved 3,800 participants with confirmed Alzheimer's, did show that Rybelsus led to reductions of up to 10% in some Alzheimer's biomarkers including several measures of tau, but most of the benefits observed were below 10%.

"We know that amyloid removal needs to be much more rigorous before we see an effect," Sano said.

The two drugs currently approved for slowing Alzheimer's, Eli Lilly's LLY.N Kisunla and Leqembi from Eisai 4523.T and Biogen BIIB.O, work by removing those amyloid deposits and were shown in trials to delay disease progression by around 30%.

Novo said the safety profile of Rybelsus was consistent with the daily pill's approved use as a diabetes treatment. Semaglutide, also sold as a weekly injection as Ozempic for diabetes and Wegovy for weight loss, is associated with side effects such as nausea.

POPULATION STUDY LIMITATIONS

Much of the evidence suggesting a cognitive benefit from GLP-1s came from large population studies of people with diabetes. Novo suggested, however, that those studies had "biases," and may have overstated the drug's impact.

Peter Johannsen, Novo's international medical vice president, on Tuesday said diabetes patients prescribed GLP-1s likely had access to endocrinologists, rather than only primary care, and may be in higher socioeconomic groups than the general population.

A Novo spokesperson said the company plans to discontinue both trials and is reviewing all data from the studies, adding that "it is too early to speculate" about whether the company will plan further research in Alzheimer's disease.

Full results of the Rybelsus trials will be presented at the 2026 Alzheimer’s and Parkinson’s Diseases Conferences in March.

(Reporting By Deena Beasley in San Diego and Julie Steenhuysen in Chicago; Editing by Bill Berkrot)

((deena.beasley@thomsonreuters.com; 213 955 6746; Reuters Messaging: deena.beasley.thomsonreuters.com@reuters.net))