PETHEMA-BLIN-01/PET069014 (BLIN-01)

The PETHEMA Spanish group treats patients with high-risk Philadelphia chromosome-negative ALL, aged 18 to 55 years, based on the MRD clearance as assessed by flow cytometry at a centralised evaluation centre. Patients with MRD \< 0.1% (\< 1×10-3) after induction and \< 0.01% (\< 1×10-4) after early consolidation are assigned to receive chemotherapy (late consolidation and maintenance). Early consolidation chemotherapy consists of three cycles including high doses of MTX, ARA-C and ASP, together with vincristine and dexamethasone. The same therapy is repeated in the late consolidation period if MRD after early consolidation is \< 0.01% (\< 1×10-4). Maintenance therapy is then administered for up to 2 years from the CR date. These patients do not receive allo-HSCT if they maintain adequate MRD clearance. Despite having adequate MRD clearance, a proportion of patients (around 25%) experience relapse, which makes other approaches necessary to try to decrease the relapse rate. Intensifying currently existing chemotherapy regimens is not likely to increase the cure rate and would likely significantly increase toxicity. The use of targeted immunotherapeutic agents such as blinatumomab, which has demonstrated efficacy and safety in patients with R/R ALL and in patients with ALL and MRD+, seems to be a promising option \[30-33\]. Therefore, it would be interesting to assess the potential efficacy of using blinatumomab in CR patients to reduce the MRD more frequently and more intensely during the early and late consolidation period. Our hypothesis is that blinatumomab will further reduce the level of MRD and this could lead to a decrease in the relapse rate in these patients. This trial will replace the third early consolidation cycle with a cycle of blinatumomab, and the same will be done in the late consolidation period. We hope that this strategy will increase the extent of the MRD response and prevent relapses. Moreover, and as a secondary objective, we will investig