Amgen’s Obesity Drug Cuts Weight by Up to 20%, Trial Data Drags Down Shares

(Reuters) -Amgen’s experimental drug MariTide helped overweight or obese patients lose up to 20% weight on average in a year-long mid-stage trial, data that missed lofty investor expectations and sent the shares down 8% before the bell on Tuesday.

Ahead of the results, some analysts had said 20% weight loss was the minimum bar and were expecting details on weight loss linked to the dose amount. The drugmaker will discuss the data on a conference call later in the day.

The 592-patient study involved a complicated design, testing several doses of the drug in overweight and obese people both with and without diabetes.

Amgen is betting on MariTide’s unique approach to grab a slice of the potential $150 billion obesity treatment market, dominated by Novo Nordisk and Eli Lilly.

MariTide is an antibody linked to a pair of peptides that activates the GLP-1 receptor while simultaneously blocking the GIP receptor.

It is expected to compete with once-weekly injections, including Novo’s Wegovy, which targets receptors for the appetite- and blood sugar-reducing hormone known as GLP-1, and Lilly’s Zepbound, which stimulates GLP-1 and a second gut hormone called GIP.

Amgen said the common side effects for trial patients were gastrointestinal, including nausea, vomiting and constipation. Nausea and vomiting were mostly mild, transient and primarily associated with the first dose.

In the study, obese or overweight patients with Type 2 diabetes, who typically lose less weight on GLP-1 therapies, achieved up to about 17% weight loss on average, Amgen said.

Amgen said about 11% of patients discontinued due to adverse events in the dose escalation arms of the study.

In patients with and without diabetes – a “plateau” was not observed, indicating potential for further weight loss beyond 52 weeks, Amgen said.

No association between the drug and bone mineral density changes was observed in the mid-stage study, a concern from early-stage data that had wiped off more than $12 billion from the company’s market value.

(Reporting By Deena Beasley in Los Angeles and Bhanvi Satija in Bengaluru; Editing by Bill Berkrot, Anil D’Silva and Arun Koyyur)