A Clinical Study of MK-1045 in People With Non-Hodgkin Lymphoma (MK-1045-008)

Inclusion Criteria:

The main inclusion criteria include but are not limited to the following:

• Has disease that has relapsed (disease progression after remission) or is refractory (failure to achieve complete or partial response) to at least 2 prior systemic linesof therapy.

• Has a histologically confirmed diagnosis of follicular lymphoma (FL) or diffuselarge B-cell lymphoma (DLBCL).

• DLBCL participants only: has progressed after or is ineligible for transplant andchimeric antigen receptor T (cell) (CAR-T) therapy.

• Has provided tumor tissue sample (archival or newly obtained, if performed perstandard of care).

• Has documented retained expression of cluster of differentiation 19 (CD19) in tumortissue obtained by biopsy after disease progression on CD19-targeting therapy, ifexperienced disease progression after prior CD19-targeting therapy.

• Has well-controlled human immunodeficiency virus (HIV) on antiretroviral therapy ifhas a history of HIV infection.

• Has undetectable hepatitis B virus (HBV) viral load and received and will continueto receive HBV antiviral therapy if hepatitis B surface antigen (HBsAg)-positive.

• Has undetectable hepatitis C virus (HCV) viral load and received HCV antiviraltherapy if has a history of HCV infection.

• Has radiographically measurable disease per Lugano Response Criteria.

Exclusion Criteria:

The main exclusion criteria include but are not limited to the following:

• Has received a solid organ transplant.

• Had or has clinically relevant central nervous system (CNS) diseases.

• Has a history of serious cardiovascular or cerebrovascular diseases.

• Had prior allogenic stem cell transplantation with acute graft-versus-host-disease (GVHD); has ongoing evidence of chronic GVHD manifesting as skin involvement,diarrhea, or increased serum bilirubin; or requires systemic immunosuppression forGVHD.

• Is HIV-infected with a history of Kaposi's sarcoma and/or Multicentric Castleman'sDisease.

• Has received a live or live-attenuated vaccine within 30 days of randomization.

• Has received prior CAR-T therapy within 3 months before the first dose of the studyintervention.

• Has a known additional malignancy that is progressing or required active treatmentwithin the past 2 years.

• Has known active CNS lymphoma or involvement.

• Has active autoimmune disease that required systemic treatment in the past 2 years.

• Has active infection requiring systemic therapy.

• Has a history of severe bleeding disorders.

• Has not recovered from major surgery or has ongoing surgical complications.

• Has diagnosis of primary mediastinal B-cell lymphoma.