The use of higher dose clofarabine in adults with relapsed acute lymphoblastic leukemia.

The standard dose of clofarabine is 52 mg/m2 for pediatrics and 40 mg/m2 in adults. Clofarabine dosed at 52 mg/m2 was used in adult patients with refractory ALL to maximize response before allo-HSCT. All patients had a significant response to therapy. Published pharmacokinetic analysis revealed no difference in peak plasma or intracellular concentrations at clofarabine dosed above 40 mg/m2, yet inhibition of replication in leukemia cells was only sustained over 24 hr at 55 mg/m2. Despite this, there have been no reports of high dose clofarabine used in this setting. Our experience implies that there may be a niche role for clofarabine in reducing disease burden before allo-HSCT for adults with relapsed ALL. Copyright 2009 Wiley-Liss, Inc.