Jorge Castillo, MD, Dana-Farber Cancer Institute, Boston, MA, comments on the results of a study investigating factors associated with progression-free survival (PFS) in patients with Waldenström’s macroglobulinemia (WM) treated with ibrutinib monotherapy. In agreement with previous studies, the study identified CXRC4 mutations as a factor indicative of a worse PFS. Interestingly, the study also showed that thrombocytopenia prior to the initiation of ibrutinib therapy was also associated with a poorer prognosis. In addition, the study did not find a predictive value for the International Prognostic Scoring System for WM (IPSSWM) in this cohort, suggesting that a larger sample size and a longer follow-up are required to validate this marker in patients with WM treated with ibrutinib. This interview took place at the European Hematology Association (EHA) Congress 2022 held in Vienna, Austria.