This study aimed to test a new combination of chemotherapeutic agents, modifying the standard treatment for relapsed AML patients by replacing fludarabine with clofarabine in combination with cytarabine and liposomal daunorubicin. The new combination regimen was well tolerated and showed high response rates. The overall response rate was 68%, which is encouraging considering that these patients (n=34) had a very dismal prognosis, since they were included at second relapse, refractory first relapse, or early first relapse. The response rate was even higher in patients treated at the recommended dose of clofarabine in combination with cytarabine and liposomal daunorubicin: at this dose level the overall response rate was 80% (n patients treated=10). Some non-responders to the standard regimen for relapsed AML were rescued with this regimen. The main side effects were bone-marrow suppression and infections, and it is advised to screen patients for subclinical fungal infections prior to treating them with this intensive reinduction chemotherapy. Considering the results of this study, clofarabine was taken forward in the front-line treatment for newly diagnosed acute myeloid leukemia (AML-BFM 2012), and this block is used in reinduction treatment of relapsed or refractory AML in the Máxima.
