A Study of BGB-21447, a Bcl-2 Inhibitor, in Mature B-Cell Malignancies

Inclusion Criteria

1. Confirmed diagnosis (per World Health Organization [WHO] guidelines, unlessotherwise noted) of one of the following: Cohort A1 and Cohort A2:

2. R/R DLBCL (for Cohort A1 and Cohort A2.1)

• High-grade B-cell lymphomas with translocations of MYC and Bcl-2 and/orBcl-6 are not allowed in Cohort A1 but may be allowed in Cohort A2.1

2. R/R FL (for Cohort A1 and Cohort A2.2)

3. R/R MZL (for Cohort A1 and Cohort A2.2)

4. Transformed B-cell NHL (for Cohort A1 only)

5. Richter's transformation to DLBCL (for Cohort A1 only)

6. Measurable disease by computed tomography/magnetic resonance imaging.

Exclusion Criteria:

1. Prior malignancy (other than the disease under study) within the past 2 years,except for curatively treated basal or squamous skin cancer, superficial bladdercancer, carcinoma in situ of the cervix or breast, or localized Gleason score ≤ 6prostate cancer or lentigo maligna melanoma that has been curatively resected

2. Known central nervous system involvement by lymphoma/leukemia

3. Prior autologous stem cell transplant < 3 months before the first dose of studydrug. Or prior chimeric antigen receptor T-cell (CAR-T) therapy < 3 months beforethe first dose of study drug

4. Prior allogeneic stem cell transplant.

5. Major surgery < 4 weeks before the first dose of study treatment

NOTE: Other protocol-defined Inclusion/Exclusion criteria may apply.