MPN-386 Real-World Ruxolitinib Treatment Pattern in Myelofibrosis Patients With Thrombocytopenia.

Abstract

Ruxolitinib, the standard treatment for patients with myelofibrosis to reduce splenomegaly and improve myelofibrosis-associated symptoms, is associated with high rates of cytopenia effect. Thrombocytopenia, common in myelofibrosis patients, is associated with poor clinical outcomes, and its treatment confers a unique challenge. This real-world study characterized the disease and ruxolitinib treatment pattern in myelofibrosis patients with thrombocytopenia using US insurance claims data. Data from the IBM MarketScan® Medicare Supplemental Database were retrospectively analyzed to identify patients aged ≥18 years with ≥1 claim for ruxolitinib and ≥2 non-diagnostic medical claims for myelofibrosis from 2017 to 2019. The first ruxolitinib claim on or after the first myelofibrosis claim defined the index date. Patients who continuously enrolled in a health plan for 3 months before and 6 months after the index date were included. Clinical characteristics and ruxolitinib treatments were compared in myelofibrosis patients with or without a history of thrombocytopenia prior to ruxolitinib initiation. Overall, 136 myelofibrosis patients who received ruxolitinib treatment were included in the analysis. The median age was 61 years, 61% were male, 62% had primary myelofibrosis, and 38% had post-polycythemia vera or essential thrombocythemia myelofibrosis. Prior to ruxolitinib treatment, 57% of patients had a diagnosis of splenomegaly, 56% had anemia, 25% had thrombocytopenia, 19% had received RBC transfusion, and 7% had neutropenia. During ruxolitinib treatment, 25% of patients had a new diagnosis of thrombocytopenia, 22% had neutropenia, and 19% had anemia. Patients with versus without history of thrombocytopenia had more anemia (79% vs. 48%, P=0.001), more red blood cell transfusions (44% vs. 11%, P<0.001), and a lower mean starting dose of ruxolitinib (20 mg vs. 27 mg, P=0.005). History of anemia, leukocytosis, neutropenia, myelofibrosis type, and splenomegaly had no effect on the ruxolitinib starting dose. Myelofibrosis patients with versus without history of thrombocytopenia continued ruxolitinib treatment at lower doses. During ruxolitinib treatment, 57% of patients with versus 42% without history of thrombocytopenia experienced anemia (OR=1.88, P=0.43). History of thrombocytopenia was a major factor influencing ruxolitinib dose and was associated with history of anemia and neutropenia. Our findings underscore the need for more treatment options to manage myelofibrosis patients with thrombocytopenia.