09:05 AM EDT, 07/10/2025 (MT Newswires) -- Health care stocks were mixed premarket Thursday, as the Health Care Select Sector SPDR Fund (XLV) was 0.1% lower and the iShares Biotechnology ETF (IBB) was recently up 0.3%.

Ultragenyx Pharmaceutical ( RARE ) and Mereo BioPharma ( MREO ) said the placebo-controlled portion of a pivotal phase 3 study of UX143, or setrusumab, for osteogenesis imperfecta is advancing to final analysis as planned, with data expected by year-end. Ultragenyx Chief Executive Emil Kakkis said the partners "had hoped to be able to stop the study early." Shares of Ultragenyx were down more than 20% and Mereo shares were over 30% lower pre-bell Thursday.