Zanubrutinib, Bendamustine, Rituximab Prev. Untreated WM

This is multi-center phase 2 of zanubrutinib, bendamustine, and rituximab (ZBR) in previously untreated Waldenström macroglobulinemia (WM). A phase II clinical trials test the safety and effectiveness of an investigational drug to learn whether the drug works in treating a specific disease. "Investigational" means that the drug is being studied. The U.S. Food and Drug Administration (FDA) has not approved bendamustine and rituximab for your specific disease, but it has been approved for other uses. The U.S. FDA has approved zanubrutinib as a treatment option for your disease. The combination of zanubrutinib, bendamustine, and rituximab is not approved regimen for Waldenström macroglobulinemia (WM) and is investigational in this study. Participation is expected for a maximum of 15 cycles and follow-up for up to 5 years. It is expected that about 50 people will take part in this research study.