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P01 A retrospective observational study of the use of rasburicase within a tertiary paediatric oncology centre

Rasburicase is used for the treatment and prophylaxis of hyperuricaemia in patients with haematological malignancy at high risk of tumour lysis syndrome (TLS). It is licensed in both adults and children at a dose of 0.2 mg/kg/day for up to 7 days. In adults off label dosing of 3 mg stat is being used for the prophylaxis of TLS and, whilst not licensed, has been recommended by the British Society for Haematology (BSH) TLS guidelines (Jones et al., 2015). Consequently this has been translated to paediatric use, with our centre using a dose of 0.2 mg/kg (max 3 mg). The aim of this audit is to establish the current prescribing practice for rasburicase within this paediatric oncology centre and ascertain whether its use is in line with BSH recommendations for TLS management in paediatrics. Method Paediatric patients who had received rasburicase within the previous 12 months were identified via the pharmacy dispensing system. For each patient data was collated from the medical notes, drug chart and blood results. The patient’s risk for TLS was defined, the intended use of rasburicase (treatment or prophylaxis) was established and each patient was assessed for laboratory and clinical signs of TLS according to BSH guidelines. Results Eleven patients received rasburicase within the previous twelve months. Six were initiated on prophylactic dosing versus five on treatment. Seven out of eleven patients were classed as high risk of TLS, three of which were given a single prophylactic dose of rasburicase and four given treatment. Of the three high risk patients who received rasburicase prophylaxis, one was capped at 3 mg and subsequently converted to treatment due to escalating TLS. This patient received allopurinol concurrently with rasburicase. Three non high risk patients received prophylactic rasburicase. Two showed laboratory signs of TLS and received capped doses of 3 mg. One patient had no access for bloods and was given an uncapped prophylactic dose. The average number of prophylactic doses given per patient was 1.8. Five out of six patients who received treatment rasburicase showed laboratory signs of TLS. The average duration was 4.1 days. Conclusion The results show inconsistency in the prescribing of rasburicase at this paediatric oncology centre, particularly for TLS prophylaxis. Some patients received capped prophylactic dosing whilst others did not. BSH guidance does not recommend a dose cap of 3 mg in paediatrics due to a lack of evidence whereas the local guideline does. One patient received both allopurinol and rasburicase – the BSH guidance advises this as unnecessary with the potential to reduce the efficacy of rasburicase. TLS treatment with rasburicase was more consistent with five out of six patients being treated in line with BSH guidance and the product license. Reference Jones GL, Will A, Jackson GH, Webb NJ, Rule S. Guidelines for the management of tumour lysis syndrome in adults and children with haematological malignancies on behalf of the British committee for standards in haematology. Br J Haematol2015;169:661–671.