Novo Nordisk faces setback Here’s what caused Ozempic Maker stock to tumble on Monday.

Novo Nordisk (NVO) shares fell Monday morning after the Danish pharmaceutical company published the latest results from a drug trial.

The company was looking to determine whether semaglutide, the active ingredient in the weight-loss drugs Ozempic and Wegovy, could also slow the cognitive decline associated with Alzheimer’s disease. The trial’s goal was to slow the decline by at least 20%. CNBC But Novo Nordisk said Monday that although the drug improved unspecified “biomarkers” related to Alzheimer’s, it did not slow the progression of the disease itself.

Analysts were unsure how likely the trial was to achieve its goals, and whether demand for Ozempic and Wegovy was still growing. Morgan Stanley analysts downgraded the pharmaceutical company’s shares in September.

“Based on the significant unmet need in Alzheimer’s disease as well as a number of indicative data points, we felt we had a responsibility to explore the potential of semaglutide, despite the low probability of success,” said Martin Holst-Lange, chief scientific officer at Novo Nordisk.

Alzheimer’s disease diagnoses and costs associated with the disease have increased as the baby boomer generation ages. Costs are expected to continue to rise in the coming years, exceeding $1 trillion by 2050. Rival pharmaceutical companies such as Eli Lilly (LLY) and Biogen (BIIB) are currently manufacturing other drugs that could slow the progression of Alzheimer’s disease.

Novo Nordisk shares, listed in the United States, fell by 6% in recent trading. The stock, which is trading at its lowest level in more than four years, has lost nearly half its value since the beginning of the year as growth in sales of weight-loss drugs slows.