shares Amgen Its shares fell more than 7% on Tuesday, as analysts reviewed bone density loss data from an early trial of its experimental weight-loss injection, MariTide.
One analyst said the additional data points to potential new safety risks associated with the drug. But others said the stock move was an overreaction, and that more data on a larger group of patients was needed.
Amgen did not immediately respond to a request for comment on the data
The drug is considered a promising potential competitor in the weight loss drug market. It is designed to be taken monthly, not once a week like existing injections Novo Nordisk and Eli Lillyand promotes weight loss in various ways.
Wall Street is awaiting the results of the crucial phase 2 trial of MariTide, which are scheduled to be released before the end of the year.
Analysts on Tuesday cited additional publicly available data from a phase 1 study that showed the highest dose of Maritide — 420 milligrams — was associated with a loss of nearly 4% of bone mineral density over 12 weeks. Low bone mineral density refers to the loss of calcium and other minerals in the bones, making them weaker and more susceptible to fracture.
In a research note, Olivia Breyer, an analyst at Cantor Fitzgerald, called the data “largely unknown” and suggested it could be a potential risk associated with drugs like MariTide, which work with so-called GIPR antagonists. Amgen injection works by blocking a gut hormone receptor called GIP but also activates another appetite-suppressing hormone called GLP-1.
This is in contrast to Eli Lilly's obesity drug, Zepbound, which activates 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.
“On the one hand, patients can naturally lose bone mineral density during weight loss treatment,” Breyer wrote.
But “on the other hand, this may be a non-starter because there appears to be a dose-dependent increase” in bone mineral density loss, Breyer said. This means that patients seem to lose more bone mineral density the higher the dose they take.
Meanwhile, Jefferies analyst Michael Yee wrote in a note that MariTide's additional data appears to be “not a problem.” Yee acknowledged that people who took the highest dose of the drug experienced a decrease in bone density, but said that “the data is all over the place.”
For example, he pointed to data on a lower dose of the drug showing that bone density actually increased by 1% before returning to normal. Yi added that “changes” in bone mineral density are a known side effect of weight-loss medications in the first one to three months of use because people lose significant weight quickly.
Amgen is also aware of “hypothetical concerns” about loss of bone mineral density, Yee said, citing the company's discussions with management.
“Although we're not clearly saying there's zero effect, we are saying we don't think there's a concern, a significant reduction in (bone mineral density) over time, a risk or a clinical concern,” Jeffries said. “Overall, we don't think there is a problem and the effect normalizes over time.”
“We would be cautious about making a blanket judgment on MariTide's safety profile using this data,” BMO analyst Evan Segerman wrote in a note Tuesday.
“We will be more comfortable judging the safety profile with a larger group of patients,” he added. There may not be a clear answer until Amgen releases full phase 2 trial data for the drug.
“Our view on MariTide has not changed with this, and if anything we view the sell-off as oversold,” Segerman wrote.
