Shares of Novo Nordisk fell to a four-year low on Monday after the Danish pharmaceutical company announced that a highly anticipated trial for Alzheimer’s disease failed to meet its primary goal.

The trial tested semaglutide, the active ingredient in Novo’s blockbuster diabetes and weight-loss drugs Ozempic and Wegovy, to see if it could slow the progression of Alzheimer’s disease. While semaglutide showed improvement in Alzheimer’s-related biomarkers in two separate trials, it did not achieve the intended effect of slowing cognitive decline by at least 20%, Novo said.

As of 1:30 p.m. London time (8:30 a.m. ET), Novo shares were down 10% to 274 Danish kroner ($42.33), marking the lowest level since mid-2021.

Analysts had already considered the trial a long shot, with Novo itself calling it a “lottery ticket.” Chief Scientific Officer Martin Holst Lange explained, “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 semaglutide’s potential, despite a low likelihood of success.”

The trial results are a setback for investors who had hoped the Alzheimer’s program might help revive Novo’s battered share price. The stock had already halved year-to-date amid multiple guidance cuts and increased competition, especially in the U.S. market.

Jefferies analysts noted, “While hopes were not high for a positive readout, potential success had perhaps kept some in the name, with this result removing a near-term upside scenario.”

Alzheimer’s disease, the most common form of dementia, remains extremely challenging to treat and is expected to impact an increasing proportion of the global population as demographics shift toward older age groups.