Phase 2 Study Of Mosunetuzumab In Patients With Chronic Lymphocytic Leukemia With Positive MRD

The purpose of this study is to assess the therapeutic efficacy of mosunetuzumab, a bispecific antibody targeting CD20 and CD3 in patients who have detectable chronic lymphocytic leukemia (CLL) after receiving Bruton's tyrosine kinase inhibitors (BTKis) for at least 6 months and have no clinical or laboratory evidence of disease progression.

Inclusion Criteria: Participants are eligible to be included in the study only if ALL the following criteria apply: 1. Age ≥18 years at the time of signing the Informed Consent Form 2. Ability to comply with the study protocol and procedures and required 3. Patients must have received ≥2 prior lines of systemic therapy, including the current BTKi 4. Patients with high-risk CLL/SLL defined as the presence of any of the following factors: progression of disease on prior covalent BTKi, or progression of disease on or within 6 months of venetoclax-based treatment, or 3 or more prior treatments, or presence of del(17p) and/or TP53 mutation, or unmutated IGHV e. Patients with CLL/SLL on continuous BTKi therapy (covalent or non-covalent) for ≥12 months and detectable bone marrow MRD4 by ClonoSEQ f. Eastern Cooperative Oncology Group (ECOG) performance score (PS) of 0 or 1 g. Adequate BM function independent of growth factor or transfusion support, within 2 weeks of screening, at screening as follows unless cytopenia is clearly due to marrow involvement of CLL: * Platelet count ≥50,000/µL; in cases of thrombocytopenia clearly due to marrow involvement of CLL (per the discretion of the investigator), platelet count should be ≥30,000/mm3 * ANC ≥1.5x109 cells/L unless neutropenia is clearly due to marrow involvement of CLL (per the discretion of the investigator) * Total hemoglobin ≥10 g/dL unless anemia is due to marrow involvement of CLL (per the discretion of the investigator) h. Adequate liver function as indicated by a total bilirubin ≤1.5 x ULN, AST, and ALT ≤3 times the institutional ULN value * In patients with CLL involvement of the liver; AST and ALT \