Efficacy and safety of cladribine: Subcutaneous versus intravenous administration in hairy cell leukemia.

Abstract

7013 Background: Hairy cell leukemia (HCL) is rare B-cell lymphoproliferative disorder. Its treatment has evolved from splenectomy with time to failure (TTF) of 19 months to Cladribine that increased complete remission (CR) rate to 90%, with only small percentage of patients relapsing at 30 months. Cladribine (CDA) is originally administered intravenously as continuous infusion for 7 days; Subsequently, it was administered subcutaneously. This study aims at comparing efficacy and toxicity of Subcutaneous (SC) versus Intravenous (IV) administration of CDA in treatment of HCL. Methods: This retrospective study included HCL patients presented to National Cancer Institute and Nasser Institute, Cairo, Egypt, during period 2004-2010. Included patients received CDA as 1st or 2nd line with minimum follow up of 12 months. All files were reviewed for baseline clinical & laboratory parameters, route of administration, response, adverse events and survival. Results: This study included 49 eligible patients, 41 patients received CDA as 1st line treatment, while 8 patients as 2nd line. Eighteen patients were treated by continuous IV infusion whereas 31 patients by SC injections. Both groups were comparable regarding baseline clinical and laboratory parameters with no statistically significant difference. At median follow up period of 33.5 months, complete remission rate was 94% in IV group versus 97% in SC group (p=0.691); median TTF for IV group was 52.9 months while that for SC group was not reached (p=0.035). The median time to achieve CR in both arms was similar. By analyzing different factors affecting TTF using multivariate analysis, route of administration proved to be the only statistically significant factor (P=0.006). Regarding adverse events, there was no difference between both groups in hematological toxicities. IV route was associated with a significant higher incidence of mucositis (p=0.02) and viral infections (p=0.01). Hepatotoxicity and neurotoxicity were higher in SC group but difference was not statistically significant. Conclusions: SC administration of cladribine is an alternative route to IV in treatment of HCL with similar response rate, longer time to treatment failure and better tolerability.