Fixed-Dose Recombinant Urate Oxidase in the Treatment of Paediatric Tumour Lysis Syndrome: A Regional Cancer Centre Experience.

BACKGROUND

Tumor lysis syndrome (TLS) is an oncologic emergency commonly seen in children with hemato-lymphoid malignancies. Recombinant urate oxidase (RUO) is used in both the prophylaxis and treatment of TLS. However, in resource-constrained countries, its role is mostly limited to the treatment of established TLS and data regarding the use of RUO and its outcome is sparse.

OBJECTIVE

To describe the outcome of Pediatric TLS following the use of a fixed - dose of RUO.

METHODS

A retrospective chart review of all children <15 years of age admitted in the Department of Paediatric Oncology, Kidwai Cancer Institute from April 2017 to July 2018 with TLS and treated with a single, fixed - dose (1.5 mg) RUO was undertaken.

RESULTS

During the study period, 255 children with hemato-lymphoid malignancies were diagnosed to be at risk of developing TLS. Of these, only 22 (8.6%) children developed TLS and received RUO. Among those with TLS, 15 (68.2%) had Acute Lymphoblastic Leukemia (ALL) while 7 (31.8%) had Non - Hodgkin lymphoma (NHL). 91% (20/22) children had spontaneous TLS and the remainder developed therapy-related TLS. Median age at presentation was 8 years (IQR 5.25,1.75) with 4.5:1 male: female ratio. The mean urate level at admission was 19.12 mg/dl (+/- 8mg/dl) (Range: 10.7-34.5). 91% (20/22) children received RUO at less than 0.15 mg/kg and the median dose of RUO was 0.05 mg/kg (IQR 0.038-0.08). Of the 22 children with TLS, 2 children failed to achieve normal serum urate levels at 24 hours in response to a single fixed-dose of RUO and hence received an extra dose of RUO. Serum urate levels remarkably declined following RUO administration from 19.12 mg/dl (+/-8) to 8.2 mg/dl (+/-3.9), 3.99 mg/dl (+/-1.6) and 2.84 mg/dl (+/-1.3) at 12h, 24h and 48h respectively. AKI was present in 15 (68.2%) children. The median eGFR of the group at diagnosis was 49 ml/min/1.73m2 (IQR 26.3, 70). None of the children required hemodialysis. No significant adverse events occurred.

CONCLUSION

Fixed-dose RUO can achieve rapid, adequate and sustained drop in serum urate levels in Paediatric TLS. It is a useful strategy for managing TLS in resource-constrained settings.