A Trial of Pirtobrutinib (LOXO-305) Plus Venetoclax and Rituximab (PVR) Versus Venetoclax and Rituximab (VR) in Previously Treated Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL)

Inclusion Criteria:

Confirmed diagnosis of CLL/SLL requiring therapy per iwCLL 2018 criteria
Previous treatment with at least one line of therapy that may include a covalent Bruton's tyrosine kinase (BTK) inhibitor
Platelets greater than or equal to (≥)50 x 10⁹/liter (L), hemoglobin ≥8 grams/deciliter (g/dL) and absolute neutrophil count ≥1.0 x 10⁹/L
Adequate organ function
Eastern Cooperative Oncology Group (ECOG) Performance Status 0-2
Estimated creatinine clearance ≥30 milliliters per minute (mL/min)

Exclusion Criteria:

Known or suspected Richter's transformation at any time preceding enrollment
Prior therapy with a non-covalent (reversible) BTK inhibitor
Patients requiring therapeutic anticoagulation with warfarin or another Vitamin K antagonist
Current treatment with strong cytochrome P450 (CYP) 3A4 (CYP3A4) inhibitors or inducers
Prior therapy with venetoclax
Central nervous system (CNS) involvement
Active uncontrolled systemic bacterial, viral, fungal, or parasitic infection
Known human immunodeficiency virus (HIV) infection, regardless of cluster of differentiation 4 (CD4) count
Allogeneic stem cell transplantation (SCT) or chimeric antigen receptor (CAR)-T within 60 days
Active hepatitis B or hepatitis C
Known active cytomegalovirus (CMV) infection
Uncontrolled immune thrombocytopenic purpura (ITP) or autoimmune hemolytic anemia (AIHA)
Significant cardiovascular disease
Vaccination with a live vaccine within 28 days prior to randomization

Patients with the following hypersensitivity:

Known hypersensitivity to any component or excipient of pirtobrutinib and venetoclax
Prior significant hypersensitivity to rituximab
Known allergy to allopurinol and inability to take uric acid lowering agent