Treatment of Relapsed or Refractory Diffuse Large B Cell Lymphoma With Ociperlimab (BGB A1217) in Combination With Tislelizumab (BGB A317) or Rituximab

Inclusion Criteria:

1. Histologically confirmed DLBCL NOS (Not Otherwise Specified), EBV+ DLBCL NOS, or high grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements with DLBCL histology (double/triple-hit lymphoma [DHL/THL]), based on the World Health Organization (WHO) 2016 classification of tumors of hematopoietic and lymphoid tissue

a. Cohort 1: participants must have positive tumor PD L1 IHC testing results as determined by local pathologist b. Cohort 2: participants must have negative tumor PD L1 IHC testing results as determined by local pathologist

2. Previously received ≥ 1 line of adequate systemic anti DLBCL therapy, defined as an anti CD20 antibody based chemoimmunotherapy for ≥ 2 consecutive cycles, unless participants had PD before Cycle 2 3.

Relapsed or refractory disease before study entry, defined as either:

a. Recurrent disease after having achieved disease remission (CR or PR) during or at the completion of the latest treatment regimen b. Stable disease or PD at the completion of the latest treatment regimen

4. Ineligible for high dose therapy/hematopoietic stem cell transplantation 5. Measurable disease as assessed by computed tomography (CT) or magnetic resonance imaging (MRI) and defined as at least 1 lymph node > 1.5 cm in the longest diameter and/or at least 1 extranodal lesion > 1.0 cm in the longest diameter, and measurable lesion (s) in 2 perpendicular diameters

Exclusion Criteria:

1. Current or history of central nervous system lymphoma
2. Histologically transformed lymphoma

Receipt of the following treatment:

1. Systemic chemotherapy, targeted small molecule therapy or radiation therapy within 4 weeks (or 5 half lives, whichever is shorter) before first dose of study drug
2. Recent treatment with another monoclonal antibody within 4 weeks before first dose of study drug
3. Investigational treatment within 4 weeks (or 5 half lives, whichever is shorter) before first dose of study drug
4. Treatment with autologous stem cell transplantation within 6 months before first dose of study drug
5. Treatment with allogeneic hematopoietic stem cell transplantation or organ transplantation
6. Treatment with anti PD-1, anti PD-L1, anti PD-L2, anti TIGIT, anti CTLA4 or other antibody or drug specifically targeting T cell costimulation or checkpoint pathways

Active autoimmune diseases or history of autoimmune diseases that may relapse, with the following exceptions:

1. Controlled Type 1 diabetes
2. Hypothyroidism (provided that it is managed with hormone replacement therapy only)
3. Controlled celiac disease
4. Skin diseases not requiring systemic treatment (eg, vitiligo, psoriasis, or alopecia)
5. Any other disease that is not expected to recur in the absence of external triggering factors

Note: Other protocol defined Inclusion/Exclusion criteria may apply