(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.
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.
Almost a third of Amgen’s portfolio is facing patent expirations that threaten to erode sales. Without obesity, the company’s current pipeline won’t be sufficient to replenish its revenue over the long term, Bloomberg Intelligence analysts said.
The weight-loss results from its 52-week trial are in the same range of what’s produced by Lilly’s Zepbound, but slightly higher than produced by Novo’s popular drug Wegovy. Zepbound helped patients lose as much as 21% of their body weight over a slightly longer period of 72 weeks in a study. Meanwhile, Wegovy helped patients lose as much as 16% of their weight in two 68-week trials, according to its label.
No Plateau
However, on a conference call with analysts, Amgen officials emphasized there was no sign of the weight loss plateauing at the end of the 52-week trial. That means MariTide has the potential to produce more weight loss if it is continued longer, the executives said.
The trial, whose primary endpoint was the amount of weight lost, also assessed how long patients could go between injections and still shed pounds. MariTide appeared to produce comparable efficacy to monthly dosing when given every other month, company officials said on a separate call with journalists. Less frequent shots could be attractive for people who don’t like getting one every week, as is required with Zepbound and Wegovy.
Smaller drugmakers like Amgen are vying to unseat giants Lilly and Novo in the booming obesity market, which is expected to hit $130 billion in sales by the end of the decade. While some companies see pill versions of the popular weight-loss shots as the next frontier in the sector, Amgen is betting on a compound that can be taken less frequently.
MariTide is an antibody-drug conjugate, or ADC, a type of molecule more commonly used as a targeted cancer treatment. One part of the medication, an antibody, blocks the GIP receptor, while two peptides mimic a gut hormone called GLP-1. Lilly’s blockbuster weight-loss shot Zepbound, meanwhile, mimics both hormones, rather than blocking GIP.
MariTide’s “only differentiation appears to be dosing frequency,” Leerink Partners analysts said in a note.
--With assistance from Naomi Kresge.
(Updates with more details on rival drugs starting in 7th graph.)
©2024 Bloomberg L.P.
