Pediatric-inspired regimen with late intensification and increased dose of L-asparaginase for adult acute lymphoblastic leukemia: the KALLA 1406/1407 study

Background/aims: The objective of this study was to evaluate the efficacy and feasibility of the pediatric-inspired regimen of the adult acute lymphoblastic leukemia (ALL) Working Party, the Korean Society of Hematology.

Methods: Data of 99 patients with newly diagnosed ALL, who were treated with the KALLA 1406/1407 protocol, were retrospectively analyzed. All patients equally received age-adjusted daunorubicin, vincristine, and prednisolone. L-asparaginase was additionally administered to Philadelphia (Ph)-negative patients according to age, whereas Ph-positive patients received 600 mg/day of imatinib.

Results: A total of 99 patients were enrolled in this study, of whom 62 (62.6%) were diagnosed with Ph-negative ALL and 37 (37.3%) were diagnosed with Ph-positive ALL. The median age of patients in the Ph-negative ALL group was 46 years, and that of patients in the Ph-positive ALL group was 49 years. In patients with Ph-negative ALL, 57 (92%) patients achieved complete remission (CR) and CR with incomplete hematologic recovery (CRi). Disease-free survival (DFS) and overall survival (OS) rates at 2 years were estimated to be 42% and 63%, respectively. In patients with Ph-positive ALL, 32 (86%) patients achieved CR/CRi, and 2-year DFS and OS were 31.2% and 49.1%, respectively. Patients who were able to proceed to the allogeneic hematopoietic cell transplantation and younger patients showed significantly superior survival in both Ph-negative ALL and Ph-positive ALL. Neutropenic fever and bacterial infection were the most common and severe adverse events.

Conclusion: The KALLA 1406/1407 protocol showed tolerable toxicities in adult ALL patients. Especially, younger patients had more survival benefits with KALLA 1406/1407 protocol.