A Study of Nemtabrutinib (MK-1026) Versus Comparator (Investigator’s Choice of Ibrutinib or Acalabrutinib) in First Line (1L) Chronic Lymphocytic Leukemia (CLL)/ Small Lymphocytic Lymphoma (SLL) (MK-1026-011/BELLWAVE-011)

Inclusion Criteria:

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

Confirmed diagnosis of CLL/SLL and active disease clearly documented to have a need to initiate therapy.
Has at least 1 marker of disease burden.
Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 within 7 days before randomization.
Has the ability to swallow and retain oral medication.
Participants who are hepatitis B surface antigen (HBsAg) positive are eligible if they have received hepatitis B virus (HBV) antiviral therapy for at least 4 weeks and have undetectable HBV deoxyribonucleic acid (DNA) viral load before randomization.
Participants with history of hepatitis C virus (HCV) infection are eligible if HCV ribonucleic acid (RNA) viral load is undetectable at screening.
Participants with human immunodeficiency virus (HIV) who meet ALL eligibility criteria.

Exclusion Criteria:

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

Has an active hepatitis B virus/ hepatitis C virus (HBV/HCV) infection.
Has gastrointestinal (GI) dysfunction that may affect drug absorption.
Has diagnosis of Richter Transformation or active central nervous system (CNS) involvement by CLL/SLL.
Has had acquired immune deficiency syndrome (AIDS)-defining opportunistic infection in the past 12 months before screening.
Has clinically significant cardiovascular disease.
Has hypersensitivity to nemtabrutinib or contraindication to ibrutinib or acalabrutinib, or any of the excipients.
Has history of severe bleeding disorder.
Has history of second malignancy, unless potentially curative treatment has been completed with no evidence of malignancy for 2 years.
Has received any systemic anticancer therapy for CLL/SLL.
Is currently being treated with p-glycoprotein (P-gp) substrates with a narrow therapeutic index, cytochrome P450 3A (CYP3A) strong or moderate inducers or CYP3A strong inhibitors.
Received prior radiotherapy within 2 weeks of start of study intervention, or radiation-related toxicities, requiring corticosteroids.
Received a live or live-attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines are allowed.
Has received an investigational agent or has used an investigational device within 4 weeks before study intervention administration.
Has diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior the first dose of study medication.
Has active autoimmune disease that has required systemic treatment in the past 2 years. Replacement therapy (eg, thyroxine, insulin, or physiologic corticosteroid) is allowed.
Has active infection requiring systemic therapy.
Participants who have not adequately recovered from major surgery or have ongoing surgical complications.