Cantor Fitzgerald analyst Olivia Brayer found supplementary bone marrow density data for Amgen’s obesity candidate MariTide that could point to a potentially greater fracture risk than previously revealed, but some other analysts view the findings as a nonissue.
Amgen lost more than 7% of its value in trading on Tuesday after reports circulated that its highly anticipated obesity candidate MariTide could have negative effects on bone mineral density, raising concerns that the investigational therapy could aggravate the risk of fractures in patients.
The bone marrow density (BMD) data were first spotted and publicized by Cantor Fitzgerald analyst Olivia Brayer, who found the figures in a supplemental source file accompanying a Phase I publication for Maritide. This paper, published in Nature Medicine, did not include bone density readings in its main body.
Brayer called the BMD data “a big surprise” in her note, as reported by StreetInsider, pointing out that the hidden figures seemed to indicate a 4% drop in BMD in patients who were treated with the 420-mg dose of MariTide over 12 weeks.
“As previously stated, Amgen does not see an association between the administration of MariTide (maridebart cafraglutide, formerly AMG 133) and bone mineral density changes,” the pharma said in a statement. “The Phase 1 study results do not suggest any bone safety concern or change our conviction in the promise of MariTide. We look forward to sharing the Phase 2 topline data later this year.”
Analysts seem to be torn about the revelation, with some conceding that BMD is an important point of concern for obesity treatments, while others believe that the new data are largely inconsequential. Even Bayer was quick to point out that the BMD data could be a “non-starter” since it is possible for bone density to naturally decline during weight loss, particularly if diet is restricted.
“There appears to be a maximum reduction from baseline in BMD of roughly 4%-5% with [MariTide] at 420 mg over 24 weeks for both the femur and hip measurements,” according to an investor note from William Blair’s Matt Phipps, who has also seen the BMD data. “The 4% reduction does appear higher than” the BMD loss in other weight-loss therapies, Phipps continued, but MariTide “does clearly result in greater weight loss over a six-month period … so we think it could be expected to also have greater reductions in BMD based on that change alone.”
In this regard, Phipps believes that Amgen’s negative stock movement is “overdone.”
Jefferies’ Michael Yee was more strongly supportive of MariTide, writing in a Tuesday note that the BMD data “seems non-issue,” pointing out that “BMD ‘changes’ are a known class effect for [weight loss] drugs.”
“We see highest dose has some declines but the data is all over the place,” Yee added, flagging similar BMD declines in the placebo group and increases in certain MariTide dose groups. “We are not overly concerned and view any pullback here as a buying opportunity ahead of the Phase II data from AMGN.”
MariTide is an investigational bispecific molecule that simultaneously blocks the GIP receptor and activates the GLP-1 receptor. Currently, the obesity candidate is in a Phase II study with a readout expected “later this year,” CEO Robert Bradway revealed in the pharma’s third-quarter earnings call last month.
