A Phase II Study of Time-limited Combination of Pirtobrutinib, Venetoclax, and Rituximab in Treatment Naïve Patients With Waldenström's Macroglobulinemia (WM) / Lymphoplasmacytic Lymphoma (LPL) (PRoVen)

Inclusion Criteria: * Age greater than or equal to 18 years * Histologically confirmed treatment naive WM/LPL (participants with non-IgM LPL are NOT eligible for the study) * Patients must have measurable disease as defined by at least one lymph node ≥1.5 cm and/ or IgM levels \> 0.5gm/dl quantified by using densitometry on serum protein electrophoresis (SPEP) or quantitative nephelometry. * Participants must have at least one of the established criteria to require therapy for WM, including anemia, thrombocytopenia, neuropathy related to WM, symptomatic hyperviscosity or serum viscosity level…