Dive Brief:

• Amgen’s experimental obesity drug MariTide helped people with obesity lose an average of up to 16% of their body weight over the course of a year, according to full data from a Phase 2 trial unveiled Monday at a medical meeting.
• That figure, however, is lower than what Amgen released in November, which only included people who completed the study and didn’t account for those who’d stopped therapy. It also appears inferior to what’s been observed in testing of Eli Lilly’s Zepbound and only slightly better than Novo Nordisk’s Wegovy, though the drugs haven’t been compared directly in a clinical trial.
• Amgen has been hoping to show MariTide, which is given every one to two months, may prove a longer-lasting alternative to weekly injections of Zepbound and Wegovy. However, its efficacy hasn’t yet proven clearly superior, and side effects such as vomiting have led to study discontinuations and changes to Amgen’s dosing protocol.

Dive Insight:

Amgen shares fell 4% on Monday after its the full data were presented at the American Diabetes Association meeting and simultaneously published in The New England Journal of Medicine.

MariTide is one many drugs trying to surpass Zepbound and Wegovy, which have powerful weight loss effects, but have to be administered frequently and chronically to deliver a lasting impact. They also come with gastrointestinal side effects. The next wave of medicines, among them prospects in Lilly and Novo’s own pipelines, are designed to be more potent and convenient while preserving muscle mass.

MariTide is among the most closely watched of those advancing therapies. Like Zepbound, it targets a pair of gut hormones called GLP-1 and GIP. But unlike Lilly’s drug, MariTide blocks GIP instead of stimulating it.

Phase 1 data released in early 2024 sparked such enthusiasm that Amgen’s market valuation increased by billions of dollars in a single day. But expectations have since cooled as the drug’s profile has become clearer.

Wall Street analysts offered differing views of the new results. For example, Baird’s Brian Skorney pointed to a high rate of vomiting, and a continuing decline in weight loss potency, as evidence MariTide won’t be able to challenge Wegovy and Zepbound commercially.

But Jefferies’ Michael Yee highlighted how instances of vomiting appeared to dissipate after the first dose, and that previous results suggested a slower, “two-step” escalation in dosing could reduce rates even further. MariTide’s Phase 3 trial will feature a three-step approach that may be even more effective and tolerable, Yee wrote in a note to clients.

Skorney, however, argued that the need to tweak dosing in such fashion could eliminate what was supposed to be a competitive advantage for Amgen. “What was billed originally as the drug with the most convenient dosing has now turned into a complicated dance ... that we think makes the profile commercially less attractive,” he wrote in his own client note.