Nilotinib with or without cytarabine for Philadelphia positive acute lymphoblastic leukemia.

• The alternance of reduced-intensity and conventional chemotherapy with nilotinib followed by SCT resulted in 4-year OS of 79.4% in Ph+ ALL

• The omission of high-dose Ara-C during consolidation resulted in a significantly higher rate of relapses without affecting overall survival

We previously demonstrated that a reduced-intensity chemotherapy schedule can safely replace Hyper-CVAD cycle 1 when combined with imatinib in adults with Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL). In the present randomized GRAAPH-2014 trial, we used nilotinib and addressed the omission of cytarabine (Ara-C) in consolidation. The primary objective was the major molecular response (MMR) rate measured by BCR::ABL1 quantification after cycle 4 (end of consolidation). All patients were eligible for allogeneic stem cell transplant (SCT), whereas those in MMR could receive autologous SCT, followed by 2-year imatinib maintenance in both cases. After the enrollment of 156 out of 265 planed patients, the data and safety monitoring board decided to hold the randomization due to an excess of relapse in the investigational arm. Among the 155 evaluable patients, 77 received Ara-C during consolidation (arm A) and 78 did not (arm B). Overall, 133 (85%) patients underwent SCT, 93 allogeneic, 40 autologous. The non-inferiority endpoint regarding MMR was reached with 71.1% (arm A) and 77.2% (arm B) of patients reaching MMR. However, the 4-year cumulative incidence of relapse was higher in arm B as compared to arm A (31.3% [95% CI, 21.1-41.9%] versus 13.2% [95% CI, 6.7-21.9%]; p=0.017), which translated in a lower relapse-free survival. With a median follow-up of 3.8 years, 4-year overall survival (OS) was 79.0% (95% CI, 70.6-89.3%) in arm A versus 73.4% (95% CI, 63.9-84.4%) in arm B (p=0.35). Despite a non-inferior rate of MMR, more relapses were observed when ARA-C was omitted without impact on survival. ClinicalTrials.gov ID, NCT02611492