Rasburicase Improves Renal Function and Uric Acid Nephropathy in Patients Developing Acute Renal Failure after Conditioning for Hematopoetic Stem Cell Transplant (HSCT).

Significant reduction in renal function secondary to protein deposition in the renal tubules is a common occurrence among patients with plasma cell dyscrasias such as Multiple Myeloma (MM) and Amyloidosis undergoing HSCT. Conditioning chemotherapy and uric acid release following cellular lysis may worsen already compromised renal function, leading to acute renal failure. Rasburicase, a recombinant urate oxidase enzyme, has been approved by the U.S. Food and Drug Administration for the treatment and prevention of hyperuricemia associated with tumor lysis syndrome in pediatric patients with leukemia, lymphoma, and solid tumor malignancies undergoing chemotherapy. We hypothesized that prompt treatment of hyperuricemia with rasburicase may prevent uric acid nephropathy and improve renal function, obviating the need for dialysis and improving the eventual outcome. Six adults, four with MM and two with amyloidosis, with rising uric acid levels after high dose Melphalan (200mg/m²) were given a single dose of rasburicase (0.15 mg/kg). At baseline, all patients had rising serum creatinine [mean: 2.1 mg/dL (range: 0.9–4.5 mg/dL)], rising BUN [mean: 27.6 mg/dL (range: 1.3–70 mg/dL)], and declining creatinine clearance (CrCL) [mean: 50.5 ml/min (range: 16–75 ml/min)]. After one dose of rasburicase, renal function significantly improved according to CrCL at 48 hours [mean: 55.2 ml/min (range: 17–82 ml/min)] and continued to improve at five days [mean: 68.2 ml/min (range: 18–109 mg/dL)]. Baseline uric acid was elevated [mean: 8.61 mg/dL (range: 7–9.9 mg/dL)] and improved 24 hours after treatment with rasburicase [mean: 0.2 mg/dL (range: 0–0.6 mg/dL)]. None of the patients required renal replacement therapy. There were no serious adverse events associated with rasburicase therapy. We therefore conclude that a single dose of rasburicase is promising in improving deteriorating renal function post high dose chemotherapy in patients with compromised renal function; further controlled studies are warranted.