Amgen Falls as Weight-Loss Shot Results Disappoint Street

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(Bloomberg) -- Amgen Inc. shares fell the most in 23 years after its experimental obesity shot failed to significantly outperform rivals and showed a high rate of gastrointestinal side effects.

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The reaction shows how high the bar is for new weight-loss drugs. While patients in the yearlong trial lost as much as 20% of their body weight, analysts had said that the shot, called MariTide, would have to help patients lose about 25% to compete with drugs from Eli Lilly & Co. and Novo Nordisk A/S. Both companies are targeting that level of weight loss for their second-generation products that are now in testing.

Amgen shares fell as much as 12% as of 11:11 a.m. Tuesday in New York, the most intraday since March 2001. Lilly shares gained as much as 6.4%. Novo closed up 1.8% in Copenhagen.

About 11% of patients discontinued MariTide because of adverse events in the study, slightly higher than discontinuation rates in key trials of the Lilly and Novo drugs. Amgen said the drug was associated with a 40% rate of vomiting, primarily in the first few days after the first dose. The company is studying a lower first dose that cut the rate of vomiting by about half, which it plans to use in final-stage studies.

Tolerability Question

“Tolerability for the drug will likely remain a question until more data at the lower titration doses is available,” JPMorgan analyst Chris Schott said in a note.

What Bloomberg Intelligence Says:

Given investor excitement ahead of this key readout, the 20% weight loss shown by Amgen’s MariTide at 52 weeks is at the low end of expectations and on par with Eli Lilly’s on-market Zepbound, while Lilly’s retatrutide and Novo Nordisk’s CagriSema will likely raise the weight-loss bar further. Discontinuation rates are in line with the class, suggesting MariTide is only differentiated by its monthly dosing, which alone is unlikely to sway payors or prescribers.

-Bloomberg Intelligence analysts Justin Kim and Amena Saad. Read the research here.

Wall Street has anxiously awaited results from the mid-stage study of 592 obese patients with and without diabetes. Investors have focused on the prospects for MariTide ever since Amgen revealed promising phase 1 data in late 2022. It has been seen as one of the lead contenders for the next generation of obesity medicines that promised even higher efficacy and more convenient dosing.