AstraZeneca's Ultomiris Misses Primary Endpoint in Late-stage Thrombotic Microangiopathy Trial

02:34 AM EDT, 07/27/2026 (MT Newswires) -- AstraZeneca (AZN.L, AZN.ST) said Monday that Ultomiris failed to meet the primary endpoint in a phase 3 trial involving adults and adolescents with thrombotic microangiopathy following a haematopoietic stem cell transplant. The ALXN1210-TMA-313 study did not show a statistically significant improvement in event-free survival through 26 weeks compared with placebo, although the drug demonstrated a trend toward treatment benefit. Separately, a previous phase 3 trial in pediatric patients showed overall survival rates of 87.2% at 26 weeks and 73.4% at 52 weeks. The drugmaker is continuing discussions with health authorities over the adult and adolescent findings, including their interpretation alongside real-world evidence.