The drugmaker's stock slumped 7% on Tuesday after analysts at Cantor Fitzgerald said their review of early-stage data on Amgen's MariTide showed a drop in bone mineral density.
"The Phase 1 study results do not suggest any bone safety concern or change our conviction in the promise of MariTide," Amgen said, adding that it looks forward to data from its mid-stage study later this year.
Shares of Amgen rose 2.5% in premarket trading after the company's statement.
Cantor analysts said they found the bone mineral density changes when reviewing supplemental data that was published along with the results in February.
But at least four analysts said the concerns were overblown, especially considering the company was conducting a mid-stage study and planned to invest in a larger late-stage trial.
A new safety signal would certainly cause alarm on any drug, but Amgen knows much more about MariTide than Street, Piper Sandler analyst Christopher Raymond said in a note.
MariTide activates the GLP-1 hormone associated with the feeling of fullness, similar to popular weight-loss drugs such as Novo Nordisk's (NOVOb.CO) Wegovy and Eli Lilly's (LLY.N) Zepbound.
But MariTide is different as it blocks the activity of another gut hormone called GIP, which has been linked to fat storage and metabolic regulation.
Analysts expect Zepbound to generate $5.7 billion in sales this year, and Wegovy to garner 57.14 billion Danish crowns ($8.15 billion) despite shortages.
($1 = 7.0142 Danish crowns)
