It catalyses the conversion of uric acid to allantoin. Allantoin is an inactive metabolite of purine metabolism, and is five to ten times more soluble than uric acid, so renal excretion is more effective. Rasburicase is unique as a treatment and prevention for renal failure associated with TLS in that it catalyses the metabolism of existing uric acid. Other options prevent uric acid formation.
Rasburicase reduces the risk of renal failure and the need for transfusion. Transfusion has been reported as required in 17 to 25% of TLS cases treated with allopurinol, and 1.4% of cases treated with rasburicase.
However, rasburicase is much more expensive than conventional therapy.