SUMMARY
This phase I/II study was conducted to determine the maximum tolerated
dose, toxicity, and efficacy of clofarabine in combination with high dose
cytarabine and granulocyte colony-stimulating factor (G-CSF) priming (GCLAC), in
the treatment of patients with relapsed or refractory acute myeloid leukaemia
(AML). Dose escalation of clofarabine occurred without dose-limiting toxicity,
so most patients were treated at the maximum dose, 25 mg/m2/day with
cytarabine 2 g/m2/day, each for 5 days, and G-CSF 5 μg/kg,
beginning the day before chemotherapy and continuing daily until neutrophil
recovery. The complete remission (CR) rate among the 46 evaluable patients was
46% (95% confidence interval [CI]
31–61%) and the CR + CR but with a platelet count
<100 x 109/l rate was 61% (95% CI
45–75%). Multivariate analysis showed that responses to GCLAC
were independent of age, cytogenetic risk category, and number of prior salvage
regimens. GCLAC is highly active in relapsed and refractory AML and warrants
prospective comparison to other regimens, as well as study in untreated
patients.