Trial of the Safety and Efficacy of Epcoritamab in Japanese Subjects With Relapsed or Refractory (R/R) B-Cell Non-Hodgkin Lymphoma (R/R B-NHL)

Main Inclusion Criteria:

• Must be at least 20 years of age, inclusive

• Japanese participants

• CD20 positivity at representative tumor biopsy

1. Part 1:

   * Diffuse large B-cell lymphoma (de novo or histologically transformed)
   * High-grade B-cell lymphoma
   * Primary mediastinal large B-cell lymphoma
   * Follicular lymphoma
   * Marginal zone lymphoma (nodal, extranodal of mucosa-associated lymphoid tissue, or splenic)
   * Small lymphocytic lymphoma
2. Part 2 :

   Arm 1:
   * Diffuse large B-cell lymphoma (de novo or histologically transformed)
   * Follicular lymphoma grade 1-3A
   * Relapsed or refractory disease and previously treated with at least 2 lines of systemic antineoplastic therapy including at least 1 anti-CD20 monoclonal antibody (mAb)-containing therapy.
   * Measurable disease by computed tomography (CT), magnetic resonance imaging (MRI) or positron emission tomography (PET)-CT scan

   Arm 2:

   • R/R FL grade 1, 2 or 3a, stage II, III, or IV, without evidence of transformation.
   * Previously treated with at least 1 prior anti-neoplastic agent, including anti-CD20 antibody
   * Must have a need for treatment initiation based on symptoms and/or disease burden (Groupe d'Etude des Lymphomes Folliculaires \[GELF\] criteria)
   * Eligible to receive R2 per investigator determination

   Arm 3:
   * One of following confirmed histologies (de novo or histologically transformed from FL or nodal marginal zone lymphoma) :

     o DLBCL, not otherwise specified (NOS)
     * "Double-hit" or "triple-hit" DLBCL
     * FL Grade 3B.
     * T-cell/histiocyte rich large B-cell lymphoma (LBCL)
   * International Prognostic Index (IPI) score ≥3
   * No prior therapy for DLBCL or FL grade 3B (G3B) other than nodal biopsy, corticosteroids, or palliative radiotherapy.
   * Eligible to receive R-CHOP per investigator determination

   Arm 4:
   * One of following confirmed histologies (de novo or histologically transformed from FL or nodal marginal zone lymphoma) including:

     o DLBCL, NOS.

     o "Double-hit" or "triple-hit" DLBCL
     * FL Grade 3B.
     * T-cell/histiocyte rich LBCL
   * Relapsed or refractory to at least one prior therapy including at least one prior anti-CD20 antibody.
   * Either failed prior autologous hematopoietic stem cell transplantation (ASCT), or ineligible for autologous hematopoietic stem-cell transplantation (HSCT)
   * Eligible to receive GemOx per investigator determination

   Arm 5:

   • History of histologically confirmed CD20+ FL Grade 1-3a without evidence of transformation.

   • In CR or PR per Lugano criteria following first-line or second-line treatment with SOC regimen, including anti-CD20 antibody, and last dose of SOC within 6 months prior to enrollment

   Main Exclusion Criteria:

   • Primary central nervous system (CNS) lymphoma or CNS involvement by lymphoma at screening

   • Participants not eligible for high dose therapy with autologous hematopoietic stem cell transplantation due to personal choice, social issues, or similar

   • Known clinically significant cardiac disease

   • Chronic ongoing infectious diseases requiring treatment (excluding prophylactic treatment)

   Exclusion criteria for Part 2, Arms 2 through 5:

   Arm 2:

   • FL Grade 3b

   • Histologic evidence of transformation to an aggressive lymphoma
   * Contraindication to rituximab or lenalidomide
   * Unwilling or unable to take aspirin prophylaxis or prophylactic anticoagulant as clinically indicated

   Arm 3:

   • Contraindication to any of the individual drugs of the R-CHOP regimen

   Arm 4:
   * Contraindication to any of the individual drugs of the GemOx regimen

   Arm 5:
   * FL Grade 3b
   * Histologic evidence of transformation to an aggressive lymphoma