The Amgen logo is displayed outside Amgen headquarters in Thousand Oaks, California, on May 17, 2023.
Mario Tama | Getty Images
Amgen The US drugmaker said on Tuesday that its experimental weight-loss injection helped obese patients lose up to 20% of their weight on average after a year in a critical mid-stage trial, as the company races to join the booming obesity drug market.
Maritide also helped patients with obesity and type 2 diabetes lose up to 17% of their weight after a year. The company said it did not observe a plateau in either group of patients, suggesting more weight may be lost after 52 weeks. Maritide was administered monthly or less frequently in the trial, which may offer an advantage over weekly injections that are common on the market.
But Amgen shares fell about 5% on Tuesday, as results appeared to be at the low end of Wall Street's lofty expectations for the drug. Before the data came out, several analysts said they wanted MariTide to show at least a 20% weight loss in the phase 2 trial, and some hoped for as much as 25%.
Wall Street is eagerly awaiting the results of the trial, which highlights how Amgen's drug could live up to popular weight-loss injections from… Novo Nordisk and Eli Lilly And a crowded field of treatments being developed by other drugmakers.
“Our feeling is that investors remain more confident in” Eli Lilly and Novo Nordisk as leaders in the weight-loss drug market, Jared Holz, a health care equity strategist at Mizuho, said in an email Tuesday. He noted that Amgen is likely a “distant third/fourth player” in this space, as MariTide likely won't enter the market until around 2027.
Amgen has only released data on the first part of the two-year trial, which is designed to test different dose sizes, schedules and regimens of MariTide. The main goal of the trial was to measure how much weight was lost, but it also examined how long participants could go between injections and still lose weight.
Notably, Amgen said patients who received the highest dose of Maritide every two months saw similar weight loss to those who took it monthly, suggesting the potential for less frequent dosing of the drug.
About 11% of patients in the trial discontinued treatment due to any adverse side effects, while less than 8% discontinued specifically due to gastrointestinal side effects. Gastrointestinal side effects were mainly mild to moderate and mainly related to the first dose of the drug.
Dose escalation, which refers to starting patients on a lower dose of MariTide and gradually increasing it until they reach a higher target dose, significantly improved rates of those side effects in the trial, according to Amgen.
“Based on this data, we believe MariTide has a unique, differentiated and competitive profile, which we will explore in Phase 3 development,” Amgen CEO Robert Bradway said in a call with investors on Tuesday after the results.
Jay Bradner, Amgen's chief scientific officer, said in an earlier interview that the company will use the results of the first part to “work out the finer details” of the design of its late-stage study of the treatment, which is “already deeply planned.” This month.
Amgen said MariTide could provide faster weight loss, possibly better weight maintenance, and lower doses than weekly injections such as Novo Nordisk's Wegovy and Eli Lilly's Zepbound. That could boost Amgen's prospects for a slice of the weight-loss drug market, which some analysts expect will be worth $150 billion annually by the early 2030s.
Late-stage studies on Wegovy showed it resulted in a 15% weight loss over 68 weeks, while Zepbound helped patients lose more than 22% of their weight over 72 weeks.
MariTide offers a new approach to weight loss compared to existing medications on the market because it is called a so-called peptide-conjugated antibody, which refers to a monoclonal antibody linked to two peptides. The peptides activate receptors for a gut hormone called GLP-1, while the antibody blocks receptors for another hormone called GIP.
This is in contrast to Eli Lilly's obesity drug, Zepbound, which activates both GIP and GLP-1. Wegovy activates GLP-1 but does not target GIP, which may also affect how the body breaks down sugar and fat.
“MariTide's synergistic molecular design requires only a fraction of the peptide supply with fewer injections and less device versus weekly injectable alternatives,” Bradner said on a call Tuesday.
Amgen shares have soared this year in anticipation of mid-stage trial data. This rally has lost momentum in recent weeks as one analyst raised questions about MariTide's potential side effects related to bone density. Amgen said it had no concerns about MariTide's bone density data.
Experimental design
The first part of the phase 2 trial followed 592 patients, including 465 patients with obesity and 127 patients with obesity and type 2 diabetes. The trial examined MariTide across 11 different patient groups, with researchers testing a variety of regimens and dose levels – 140, 280 and 420 milligrams.
For example, some groups have used rapid dose escalation, which involves starting patients on a lower dose of Maritide and gradually increasing it over four weeks until they reach a higher target dose. Others had a slower dose escalation over 12 weeks.
Several groups took Maritide once a month, while one group took the highest dose of the drug every two months. In an interview, Bradner noted that type 2 diabetes patients “are known to respond less favorably to weight-loss medications,” so Amgen did not put them in any groups that used escalating doses or less frequent dosing regimens.
More than 90% of eligible patients agreed to participate in the second part of the trial, which studies the longevity of weight loss with MariTide. The company is “interested in seeing how quickly people who have lost weight recover when they stop the drug,” Bradner said in the interview.
The second part of the trial is also evaluating any gradual weight loss after the first year of using MariTide and testing less frequent dosing of the drug. Amgen did not say when it would publish data for the second part of the trial.
Patients who continued the trial were randomly assigned to several groups.
For example, patients who took 140-milligram doses of MariTide in the first part of the trial will either continue on that dose or switch to a placebo for another year, which will measure how long weight loss with MariTide is sustained. Some people who took doses of 280 milligrams in the first part of the trial will take lower doses of the drug for a year.
Amgen is also testing a quarterly schedule among some patients who took the 420-milligram doses in the first part of the trial. This means patients will receive one dose every 12 weeks.
