The pharmaceutical company's MariTide treatment performed well in a Phase 2 study but not as well as Wall Street expected.

Amgen's experimental drug MariTide helped overweight or obese patients shed up to 20% of their body weight in a mid-stage trial, but the results failed to meet lofty investor expectations and shares of the biotech company tumbled about 12% on Tuesday.

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.