AstraZeneca's Ultomiris Fails Late-Stage Trial in Rare Transplant Complication

AstraZeneca (AZN) said that its rare disease therapy Ultomiris failed to meet its primary endpoint in a late-stage trial enrolling adults with a serious blood vessel complication that can arise following stem cell transplants, adding to a string of clinical setbacks that have raised questions about the company's trial design capabilities.

The drug, known chemically as ravulizumab, did not achieve statistical significance for event-free survival at 26 weeks in patients with haematopoietic stem cell transplant-associated thrombotic microangiopathy, though AstraZeneca said the data showed a trend toward benefit. The company said it is in ongoing discussions with global health regulators over potential next steps for the adult indication.

The adult trial failure was partially offset by more encouraging data from a separate pediatric study, in which Ultomiris demonstrated an overall survival rate of 87.2 percent at 26 weeks and 73.4 percent at 52 weeks. AstraZeneca said it intends to advance regulatory filings for the drug's use in children.

The result compounds a difficult stretch for the Cambridge-based drugmaker. Earlier this month, a pivotal heart disease drug developed with Ionis Pharmaceuticals failed its late-stage trial, and in May a U.S. regulatory advisory panel rejected the breast cancer candidate camizestrant, in both cases citing concerns over trial design. The pattern has drawn scrutiny from investors and analysts over how AstraZeneca constructs its pivotal studies.

Not all Astrazeneca’s news was negative. The company reported that its experimental gastric cancer drug sonesitatug vedotin met a key objective, delivering a statistically significant and clinically meaningful improvement in overall survival among patients with advanced gastric cancer — a result that may support future regulatory submissions.

Ultomiris is already approved in the United States, the European Union and Japan for a range of rare blood disorders and neurological conditions, making it one of the company's established rare disease franchises.

AstraZeneca, which beat second-quarter profit expectations on the back of robust demand for its oncology and rare disease portfolios, is counting on as many as 20 new drug launches to help it reach $80 billion in annual revenue by 2030. Monday's trial failure, while not disqualifying to that ambition, underscores the execution risk inherent in a pipeline of that scale.