ASPEN (NCT03053440) is a Phase 3, open-label, randomized trial comparing zanubrutinib with ibrutinib in activating MYD88 mutated (MYD88MUT) Waldenström’s macroglobulinemia (WM) patients. In an additional cohort, the efficacy and safety of zanubrutinib in MYD88 wild-type (MYD88WT) WM patients were evaluated.