David Leaf, MD

Tumor lysis syndrome (TLS) is a life-threatening emergency that occurs when large numbers of cancer cells break down rapidly, releasing substances such as uric acid into the bloodstream that can damage the kidneys and cause serious complications.

Although rasburicase has been widely used as a treatment for TLS for more than two decades because it rapidly lowers uric acid levels, no previous study had rigorously shown that it improves the outcomes that matter most to patients, such as preventing dialysis or death.

To address this knowledge gap, researchers analyzed data from 1,276 adults treated for TLS at 36 U.S. hospitals between 2014 and 2023. Using an emulated target trial—a rigorous study design that approximates a randomized clinical trial using real-world data—they compared outcomes among patients who received rasburicase within 12 hours of developing TLS with those who received it later or not at all. The study was led by senior author David Leaf, MD, of Mass General Brigham.

Patients who received early rasburicase were about one-third less likely to require dialysis or die during their hospital stay compared with those who received delayed or no rasburicase treatment.

The researchers estimated that providing early treatment of rasburicase would have prevented one case of dialysis or death per 11 patients. Early treatment was also associated with lower 90-day mortality and a faster return to cancer therapy.

The greatest benefit was seen among patients who were already the sickest, including those who had moderate-to-severe kidney injury, when TLS developed.

Published in BMJ on June 9, 2026 | Read the paper: “Early treatment with rasburicase and risk of kidney replacement therapy and death in adults with tumour lysis syndrome: emulated target trial” 

Summary reviewed by: David E Leaf, MD, senior author