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 * 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 levels greater than 4.0 centipoises, WM-associated glomerulonephriti…