The pharmaceutical manufacturer Amgen announced on Tuesday that an experimental obesity drug helped patients lose up to 20 percent of their weight in a year. The drug, MariTide, is given by injection once a month, compared with once a week for other obesity drugs like Wegovy and Zepbound that are already on the market.

With Amgen’s MariTide results at the lower end of investors’ expectation of 20% to 25% weight loss, the much-anticipated readout sent the company’s shares tumbling.

Amgen's experimental drug MariTide led to an average weight loss of up to 20% in a year-long mid-stage trial of nearly 600 people who were overweight or obese, the company said on Tuesday.