Hidden MariTide Data Results In $12B Drop In Amgen Stock, Partial Recovery Follows

A hidden tab in an Excel file published nine months ago has significantly impacted Amgen’s market value, erasing $12 billion from its market capitalization. The tab contained previously undisclosed data on bone density changes observed in patients during a Phase 1 trial of Amgen’s obesity drug candidate, MariTide. Initially published in the journal ‘Nature Metabolism’ in February, the data did not mention bone density. 

Amgen shared the source data in Excel files accompanying the study. While the visible tabs in the spreadsheets showed no bone density information, hidden tabs revealed by right-clicking on visible tabs contained crucial details. An analyst from Cantor Fitzgerald, Olivia Brayer, uncovered the hidden tabs and flagged the findings in a recent investor note. These hidden tabs included bone density scan data for the femur, lumbar spine, and hip and patient-level data for the highest MariTide dose group. 

A fourth tab, called “DEXA cohort 9 four,” contains patient-level data for the top MariTide dose. The hidden tab shows patients receiving the highest dose experienced an average 4% loss in bone mineral density over 12 weeks, with one participant significantly influencing the results. Cantor analyst Olivia Brayer described bone density as a potential risk associated with GIPR antagonists like MariTide. Brayer also called the data a “big unknown” in a research note, according to CNBC.

Following the publication of Brayer’s note, Amgen’s shares dropped 7%, reflecting the weight investors place on MariTide’s success ahead of its Phase 2 trial results expected later this year. However, investor confidence began to rebound, with shares rising 3.6% pre-market on Wednesday, recovering nearly half of the earlier losses. The dramatic market reaction underscores the critical role MariTide plays in Amgen’s portfolio and its upcoming clinical milestones.

Still, Jefferies analyst Michael Yee termed the bone density finding a "non-issue" in a note published in response to the brouhaha, arguing that "the data is all over the place." Amgen weighed in with its statement on the data.

“As previously stated, Amgen does not see an association between the administration of MariTide and bone mineral density changes. The phase 1 study results do not suggest any bone safety concerns or change our conviction in the promise of MariTide. We look forward to sharing the phase 2 topline data later this year,” said the company.