Real-World Use of Ruxolitinib in Patients with Myelofibrosis and Anemia or Thrombocytopenia at Diagnosis

Introduction: Ruxolitinib is approved for treatment of myelofibrosis. We evaluated ruxolitinib in patients with anemia (hemoglobin <10 g/dL) or thrombocytopenia (platelet count <= 100 x 10(9)/L) at diagnosis. Methods: This was a retrospective, secondary analysis of a Cardinal Health Oncology Provider Extended Network medical chart review of adults with myelofibrosis diagnosed between 2012 and 2016 who received first-line ruxolitinib. Results: 176 patients received first-line ruxolitinib and were included in this analysis. At diagnosis, 120 patients had hemoglobin concentrations <10 g/dL and 59 had a platelet count <= 100 x 10(9)/L. Most patients (95%) with thrombocytopenia also had anemia. Median time of observation after diagnosis was 21.4 months. Among patients with anemia or thrombocytopenia, ruxolitinib dose at end of study was >= 10 mg twice daily (bid) in 88.3% and 83.1%, respectively. Ruxolitinib treatment was ongoing in 76.1% of patients overall and was rarely discontinued for anemia or thrombocytopenia (n = 2 total, 1.1%). Per the treating physician, 79.7% of patients had improved symptoms and 62.7% improved spleen size. Conclusion: Most patients with myelofibrosis and anemia or thrombocytopenia at diagnosis tolerated and maintained a ruxolitinib dose >= 10 mg bid for nearly 2 years, resulting in clinical benefit. This real-world evidence supports observations from prospective clinical trials of ruxolitinib in myelofibrosis.