Ultragenyx Stock Declines After Missing Primary Endpoints on its Phase III Orbit and Cosmic Studies
NEW YORK, Jan. 23, 2026 /PRNewswire/ -- Levi & Korsinsky, LLP is investigating Ultragenyx Pharmaceutical Inc. (Nasdaq: RARE) following the Company's announcement of topline results from its Phase III Orbit and Cosmic Studies, focusing on the effectiveness of setrusumab (UX143) on Osteogenesis Imperfecta. Investors with concerns about Ultragenyx's business operations may click here for more information.
Ultragenyx reported the study results on December 29, 2025. Both studies failed to achieve their primary endpoint of a reduction in annualized clinical fracture rate against placebo in the Orbit study and against biophosphonates, the standard care, in the Cosmic study.
The Phase III studies also failed to correlate the secondary result to a reduction in fracture rate, despite successfully showing an improvement in the tested patients' bone density. Ultragenyx had previously relied on the results Phase II of the Orbit study to claim a causal link between improved bone density and a reduction in annualized fracture rate.
In announcing the results, the company pointed to a "low fracture rate in the placebo group" as a justification for Orbit's failed results. Management had previously highlighted there were no "uncontrolled factors" in the study and they had crafted the study in such a way to "actually increase their fractures, which would give [them] more opportunities to see the difference between [the test groups]."
Analyst coverage following the results turned cautious as analysts quickly began slashing their price targets. Barclays noted it now sees "limited opportunity for drug approval despite some trend of clinical benefit."
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SOURCE Levi & Korsinsky, LLP
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