Relevant Clinical Factors in Patients with Myelofibrosis on Ruxolitinib for 5 or More Years

Introduction: Median duration of therapy with the first JAK1/2 inhibitor ruxolitinib (RUX) approved for patients with intermediate or high-risk myelofibrosis (MF) is about 3 years. Methods: In this retrospective study, we aimed to evaluate clinical features, predictive factors, and outcome of patients presenting to our institution who were able to remain on RUX for ≥5 years (RUX ≥5y, n = 73). Results: Comparing baseline demographics of patients who remained on RUX ≥5y (n = 73) with patients who were on RUX for 6 months to 3 years (n = 203), we confirmed that patients on RUX ≥5y lacked advanced clinical features at the start of therapy, such as anemia, neutropenia, thrombocytopenia, higher blasts or monocytes. Predictive independent factors for staying on RUX ≥5y were hemoglobin >10 g/dL, circulating blasts <1%, platelets >150 × 10⁹/L, neutrophils >70%, and having primary MF. Age over 65 years remained significant for outcome in patients on RUX ≥5y. Conclusion: In this retrospective study, we report on the relevance of absence of advanced clinical features for long RUX therapy and confirm the role of age on outcome despite therapy.