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.

Amgen's experimental weight loss injection, MariTide, showed up to 20% weight loss in patients without diabetes and 17% in those with diabetes after a year in a phase 2 trial. Despite higher discontinuation rates compared to other drugs,

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.

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

Shares of Amgen (NASDAQ: AMGN) are down by 6% in the last 30 days as I write this -- a larger-than-normal amount for a large pharma company's stock to fall, especially considering that the market rose nearly 3% in the same period.