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.
Amgen’s hotly anticipated weight loss data for MariTide is finally here: The antibody peptide conjugate led to weight loss of up to 20% on average at week 52 in people who were overweight or had obesity.
The Phase II data left open questions about efficacy when adjusted for placebo, as Amgen did not report that measure. BMO Capital Markets said that is the endpoint investors were specifically hoping to see with this data drop. Jefferies analysts said the “data [are] OK - but not the bull case scenario yet.”
Investors had been looking for weight loss of 20% to 25%, so the results fall on the lower end of that range. But Jefferies said there was no plateau as the study reached its end stages, meaning more weight loss could be achieved after that point.
“Bulls will be a little disappointed today, while bears will say Amgen is no longer a major player here to be concerned on,” Jefferies wrote.
In response, Amgen’s shares tumbled more than 11% to $260.75 apiece as the markets opened Tuesday. BMO predicted the decline, saying that investors may respond to the perceived lower placebo-adjusted efficacy. They also could be girding for a more negative full readout.
How Does MariTide Compare to GLP-1s for Weight Loss?
For now, the MariTide data are pretty similar to what Eli Lilly’s Zepbound (tirzepatide) achieved at its highest dose in the Phase III SURMOUNT-1 trial in a similar patient group, Leerink Partners analysts said in a note to investors. The data also showed “robust and clinically meaningful improvements” in certain cardiometabolic measures such as blood pressure and triglycerides, the group wrote.
BMO agreed that the data are “robust.”
On safety, Amgen noted that there was no association between MarTide and bone mineral density changes—a direct response to a recent report that the drug could increase the risk of fractures. The most common adverse events were gastrointestinal, including nausea, vomiting and constipation. All of these are common side effects of GLP-1 treatment. Amgen said the events in the trial were mild, transient and generally occurred with the first dose, with rates of nausea and vomiting tapering off with dose escalation.
The discontinuation rate due to any adverse event was 11% and less than 8% for gastrointestinal-related events. BMO said the tolerability profile seems to be better than expected, while Jefferies disagreed, calling it just “ok but a little bit higher on most areas.”
Amgen’s Jay Bradner, executive vice president of R&D and chief scientific officer, said the results give the company confidence in kicking off the Phase III MARITIME study for participants with obesity and related conditions. Meanwhile, the second part of the Phase II trial will continue evaluating weight loss beyond the 52-week mark as well as durability and weight maintenance after discontinuing MariTide.
BMO called the overall results “encouraging for further development,” particularly with monthly dosing, compared with weekly GLP-1s. Executives touted the potential for less frequent dosing than existing weight loss options on a Tuesday morning conference call, suggesting that this alone could put Amgen ahead of the pack. So far, the ongoing study has tested monthly and every-other-month dosing; the latter part will also examine quarterly administration.
“Overall the profile looks more or less similar to tirzepatide but is monthly and could have even less frequent dosing,” Jefferies said.
