Zanubrutinib in Patients With Waldenström's Macroglobulinemia, Chronic Lymphocytic Leukemia, Marginal Zone Lymphoma and Follicular Lymphoma

This study tests zanubrutinib — a targeted oral drug that blocks a cancer cell survival signal (BTK inhibitor) — in patients with Waldenström's macroglobulinemia, a rare slow-growing blood cancer. **You may be eligible if...** - You have been diagnosed with Waldenström's macroglobulinemia (a rare blood cancer) - You have relapsed or your disease has not responded to prior treatment - You are 18 or older - You have adequate blood counts and organ function **You may NOT be eligible if...** - You have had prior BTK inhibitor therapy (like ibrutinib or acalabrutinib) - You have active bleeding or are on anticoagulants that cannot be paused - You are pregnant or breastfeeding - You have severe heart arrhythmias Talk to your doctor to see if this trial is right for you.