Sevelamer hydrochloride: a novel treatment of hyperphosphatemia associated with tumor lysis syndrome in children.

Background: Sevelamer is a phosphate-binder used effectively for the treatment of hyperphosphatemia in patients treated with dialysis.

Objectives: To describe the safety of sevelamer in children with hyperphosphatemia secondary to tumor lysis syndrome and the serum phosphate concentrations observed following its administration.

Procedure: A retrospective chart review of all children with leukemia/lymphoma diagnosed between November 2002 and April 2004 who received sevelamer during their initial admission was conducted. We monitored the effects of sevelamer on serum phosphate concentration, calcium/phosphate product and renal function at hours 24, 48, and 72 from sevelamer initiation.

Results: Thirteen patients received sevelamer during the study period. Their median age was 13 years (range 2.7-17.9) and eight were boys. Nine children had acute lymphoblastic leukemia, one had acute myeloid leukemia and 3 had non-Hodgkin's lymphoma. The most frequently used dose of sevelamer was 400 mg orally twice daily. The median duration of sevelamer therapy was 2 days (range 1-7). Two children were excluded from the efficacy analysis due to concurrent use of dialysis. Mean serum phosphate levels decreased after sevelamer administration, in eleven patients, from a baseline 2.2 mmol/L +/- 0.4 (95% CI, 1.7-3.1) to 1.1 mmol/L +/- 0.2 at hour 72 (95%CI, 0.6-1.5). The only toxicity attributed to sevelamer was mild vomiting in three patients.

Conclusions: Sevelamer appears to be effective and tolerable for the treatment of hyperphosphatemia associated with tumor lysis syndrome.