Current outcome of very early relapse of acute lymphoblastic leukemia (ALL) in children remains poor. As a single agent, clofarabine provided a response rate of 26% in childhood ALL second relapse and, in combination with cyclophosphamide and etoposide, a 44% complete remission and complete remission without platelet recovery (CR+CRp) rate. Further multi-drug combinations need to be investigated. We used the VANDA regimen as a template, cytarabine being replaced by clofarabine.Patients and methods.
A phase I study combining escalating doses of clofarabine (25% increments from 20 to 40 mg/m2/d) with fixed doses of mitoxantrone, etoposide, asparaginase, and dexamethasone was undertaken in children presenting with very early or second or post-transplant ALL relapse.Results.
Twenty patients were enrolled, 19 were evaluable. Four patients had previously been allografted. Dose-limiting toxicity (DLT) appeared at dose level 3 (32 mg/m2), one out of six patients experienced a liver DLT. At dose level 4 (40 mg/m2), four DLT occurred (two fungal infection and two liver DLT). The maximum tolerated dose (MTD) of clofarabine was thus determined to be 32 mg/m2. There was no toxic death. Eleven (57.9%) patients achieved a CR. Six patients proceeded to allogeneic stem cell transplantation.Conclusion.
Clofarabine MTD was 32 mg/m2/d in this combination which appeared feasible and effective in this population. Pediatr Blood Cancer © 2015 Wiley Periodicals, Inc.