However, the pharmacokinetics of clofarabine in adults with relapsed or refractory AML following administration of a single dose of 40 mg/ m2 clofarabine by intravenous infusion over 1 hour were comparable to those described above in patients aged between 2 to 19 years old with relapsed or refractory ALL or AML following administration of 52 mg/ m2 clofarabine by intravenous infusion over 2 hours for 5 consecutive days.