Isatuximab in Adult Patients With Cytologic or Molecular Relapsed/Refractory CD38 Positive T-cell Acute Lymphoblastic Leukemia

Inclusion Criteria: \- Patients with CD38 positive T-ALL fitting either to the definitions for cohort 1 or cohort 2: Cohort 1: In relapse or with primary refractory disease defined as ≥5% blasts in bone marrow after at least three chemotherapy cycles (induction I-II, consolidation I) with the following additional specifications: * early relapse within 12 months from first achievement of CR or * late relapse later than 12 months from first achievement of CR or * primary refractory disease without any CR or * any relapse after stem cell transplantation or * any refractory relapse, defined as no response to at least one salvage therapy or * any second or later relapse and * Availability of patient material with blast cells (bone marrow or peripheral blood) for central MRD assessment or availability of respective predefined marker. Cohort 2: In complete hematological remission (defined as less than 5% blasts in bone marrow and no evidence of extramedullary disease) after at least three chemotherapy cycles (induction I-II, consolidation I) * Detection of quantifiable MRD at a level of ≥10-4, either as molecular failure without prior achievement of molecular remission or molecular relapse after prior achievement of molecular remission * MRD assay at the central reference lab with at least one marker a minimum sensitivity of 10-4 * MRD detection for study inclusion after an interval of at least 2 weeks from last systemic chemotherapy including antibody therapy * (in patients wi…