Happy Thursday! Wall Street is chewing over critical data released last week on Amgen's experimental weight loss injection – a potential competitor in the blockbuster obesity drug market.
Some analysts said the initial mid-stage trial results appear positive overall. But questions remain about the drug's efficacy and how well patients tolerate it, they noted.
We likely won't get more answers until the company releases the full data from the study. That includes results from a second part of the trial, which will examine how long MariTide's weight loss lasts. More than 90% of eligible patients in the first part of the study agreed to participate in the second.
Investors initially weren't pleased. Shares of Amgen tumbled more than 11% as the markets opened last Tuesday, as the results appeared to be slightly below Wall Street's lofty expectations for the drug.
The injection, MariTide, helped patients with obesity lose up to 20% of their weight on average after a year, with no plateau. Ahead of the data, several analysts said they wanted MariTide to show weight loss of at least 20% in the phase two trial, with some hoping for up to 25%.
Here's how that compares to the existing injections on the market: Late-stage studies on Novo Nordisk's Wegovy showed that it led to 15% weight loss over 68 weeks, while Eli Lilly's Zepbound helped patients lose more than 22% of their weight over 72 weeks.
But in a note last week, BMO Capital Markets analyst Evan Seigerman said the stock reaction last Tuesday reflects "too-high expectations for % weight loss, without assigning value to easier dosing" of the injection.
Notably, Amgen is testing MariTide as an injection taken once a month or even less frequently, which would be far more convenient for patients to take long term than the weekly injections from Novo Nordisk and Eli Lilly.
"MariTide data firmly establishes Amgen as a competitor in obesity and diabetes indications, today showing compelling weight loss in both indications," Seigerman said.
In the trial, MariTide also helped patients with obesity and Type 2 diabetes lose up to 17% of their weight after a year.
The drug's efficacy may also improve, Jefferies analyst Michael Yee said in a note last week. The 20% weight loss after one year, with no plateau, may increase to 25% by 18 months, Yee said. He noted that in comparison, the weight loss caused by Zepbound mostly plateaued by a year.
The most common side effects for MariTide were gastrointestinal, including nausea, vomiting and constipation. Nausea and vomiting were mainly mild and associated with the first dose of MariTide.
Amgen said incidences of nausea and vomiting were also significantly reduced with dose escalation, which refers to starting patients at a lower dose of MariTide and gradually increasing it over a specific time period until they reach a higher target dose.
Roughly 11% of patients in groups with dose escalation discontinued treatment because of any adverse side effects, while less than 8% stopped specifically due to gastrointestinal side effects such as nausea and vomiting.
Amgen reported that 70% of patients in groups with dose escalation experienced nausea and 40% experienced vomiting.
However, Amgen said it conducted another early-stage study that found starting patients with lower initial doses of MariTide cut those rates substantially, leading to about 50% of patients reporting nausea and 20% reporting vomiting.
That appears to be higher than the levels of nausea and vomiting seen for Zepbound and Wegovy. Still, Seigerman said the mild severity of those side effects and "isolated time of events at the start of treatment give us confidence they can be managed."
He added that he is "encouraged by the reductions seen with dose escalations."
In a research note last week, JPMorgan analyst Chris Schott said Amgen will explore lower starting doses in its phase three trial on MariTide. The firm believes that "further improved tolerability in the Ph3 trial will be key to potential uptake for the asset," he noted.
Leerink Partners analyst David Risinger, in a note last week, outlined key questions that need clarification when full results from the trial are released.
He said that includes detailed data on how well patients tolerated the drug when dose escalation wasn't used, and weight loss data among non-diabetic patients that received the highest dose of the drug.
