Inclusion Criteria:  All patients:  Evidence of CD19 and/or CD22 cell surface expression on B-ALL blasts in bone marrow or peripheral blood by flow cytometry at time of relapse or prior to study entry.  Pediatric, adolescent and young adult ALL patients:  1 - 29 years of age at the time of informed consent form (ICF) signature. Relapsed or refractory CD19+ and/or CD22+ ALL after 3 or more lines of treatment OR after allogeneic HCT. Must have received a CD19-directed CAR-T treatment (with or without blinatumomab), unless prior loss of CD19 cell surface expression occurred or have not been eligible for CD19 directed CAR-T treatment. Lansky (age < 16 years), Karnofsky (age 16-25 years) performance status ≥ 60%. ECOG (age >25 years) performance status that is either 0 or 1 at screening.  Adult ALL patients aged ≥30 years:  ≥30 years of age at the time of informed consent form (ICF) signature.  Refractory or relapsed CD19+ and/or CD22+ ALL including at least one of the following:  After allogeneic HCT After 2 or more lines of treatment, including blinatumomab and/or inotuzumab Primary refractory disease (defined as failure to achieve a CR at the end of at least 1 induction chemotherapy) First relapse occurring within 12 months from first remission ECOG performance status that is either 0 or 1 at screening.  Exclusion Criteria:  Allogeneic HCT within 12 weeks prior to screening. Presence of isolated extra-medullary disease, testicular involvement or bulky disease Patients with concomitant genetic syndromes associated with bone marrow failure states: such as patients with Fanconi anemia, Kostmann syndrome, Shwachman syndrome. Patients with Burkitt's lymphoma/leukemia History of active neurological auto immune or inflammatory disorders  Other protocol-defined inclusion/exclusion criteria may apply.