Real-world disease burden for patients (pts) with myelofibrosis (MF) treated with ruxolitinib (RUX).

Abstract

e19539 Background: MF is an aggressive myeloid neoplasm and until recently RUX was the only treatment available. Real-world, long-term outcomes in pts with MF have not been described. Methods: Providers from multiple community oncology clinics in the USA reviewed the charts of consecutive pts with MF (primary or post-polycythemia vera/essential thombocythemia MF) who received RUX at any time from Jan 1, 2015 to Dec 31, 2017; data were collected Nov 15–26, 2019. Pt characteristics, treatment patterns, and outcomes (symptoms, blood counts, disease transformation) were retrospectively abstracted into an electronic case report form (eCRF) at each visit during the first 6 months, at any RUX dose modification; and at 12, 24, and 36 months post-RUX initiation. Pt characteristics, treatment patterns, rationale for dose modification, and treatment duration are described for pts during the first 6 months of therapy. Results: eCRFs were completed for 104 pts with MF treated with RUX. 42 pts received a RUX dose modification and 62 did not. Median follow-up from RUX initiation was 23.5 months. In the first 6 months of therapy, 40.4% of pts had a RUX dose modification (76.2% dose reduced; 23.8% dose increased). The most common reason (70%) for dose increase was titration to therapeutic dose. The most common reason (75%) for dose reduction was hemoglobin 8–10 g/dL or platelet count 50–75 × 109. The starting dose of RUX was higher for no RUX dose modification pts (mean total daily dose 34.9 mg vs 27.0 mg, P < 0.01). RUX dose-modified pts were older vs pts with no RUX dose modification ( P = 0.01); International Prognostic Scoring System (IPSS) risk score ( P = 0.89) and the proportion of pts with primary MF ( P = 0.06) were similar (Table). Overall, 64.4% of RUX treated pts discontinued therapy (RUX dose-modified 78.6%; no RUX dose modification 54.8%, P = 0.01). Median duration of RUX treatment was 11.0 months (RUX dose modified 10.6 months; no RUX dose modification 12.2 months; log rank P = 0.12). Conclusions: In this real-world study, 64.4% of pts discontinued RUX during follow-up. Higher rates of discontinuation and shorter time to discontinuation were noted for pts with a dose modification during the first 6 months of therapy. Given the short duration of therapy observed in this study as compared with published clinical trials, additional MF treatments are needed that offer pt benefit. [Table: see text]