Subcutaneous Blinatumomab for Treatment of Adult Patients With CD19-Positive Mixed Phenotype Acute Leukemia (MPAL)

This is a multicenter, non-randomized, open-label, phase II study evaluating blinatumomab administered subcutaneously in adult subjects with CD19+ MPAL. This trial consists of three cohorts of patients with CD19-positive MPAL, categorized as follows: 1. Cohort A: Newly diagnosed CD19+ MPAL in untreated patients who are either ≥ 75 years of age or have at least one coexisting condition precluding intensive chemotherapy. 2. Cohort B: Patients with CD19+ MPAL who have achieved complete remission (CR, CRh, or CRi) following at least one line of treatment but have detectable measurable residual disease (MRD) at a level of ≥ 0.1%, assessed using an assay with a minimum sensitivity of 0.01%. 3. Cohort C: Patients with CD19+ MPAL with morphologic relapsed or refractory (R/R) disease following at least one prior line of treatment. The Primary Objectives for each cohort are for Cohort A: to evaluate the efficacy of SC-blinatumomab in treatment; for Cohort B: to assess the ability of SC-blinatumomab to achieve MRD-negative CR; for Cohort C: to determine the efficacy of SC-blinatumomab in inducing CR, CRh, or CRi in patients. At specified time points, subjects will undergo the following procedures: collection of informed consent, medical history, demographics, ECOG performance, and physical exam including vital signs as well as neurological examination including examination of writing ability. Subjects will provide samples for complete blood count with differential and blood chemistry profile, have a bone marrow aspiration and biopsy and lumbar puncture will be performed per protocol or if clinically indicated, and/or ECG, Echocardiography, pulmonary function test will be performed only if medically indicated. The subcutaneous treatment will be given in both the inpatient and outpatient setting. For an individual subject the length of participation includes up to a 3-week screening period, up to a 13-month treatment period, and a safety follow-up visit (30 days after the last dose of study treatment), and a follow-up period.