PB2056: MYELOFIBROSIS IN PATIENTS OLDER THAN 70 YEARS: IS TREATMENT WITH RUXOLITINIB WORTH IT?

Abstract

Background: Myelofibrosis is an agressive myeloproliferative neoplasm with a higher incidence in older patients who have worse prognosis. In last years, ruxolitinib, a JAK1/2 inhibitor that may control myelofibrosis (MF)-related splenomegaly and symptoms, han been used in this disease regardless of age. Aims: Fifty three patients treated with ruxolitinib between April 2012 and March 2021 from a clinical database of 149 patients were studied in order to assess the effect of age in survival and toxicities Methods: Diagnosis of primary MF (PMF) an post-Essential Thrombocytemia /post-Polycithemic MF was made according to the WHO 2016. Molecular tests for detection for JAK2, MPL and CALR mutations were performed. Ruxolitinib starting dose was decided accordingly to prescribing information.Survival analysis was performed by means of Kaplan-Meier curves and differences between KM curves were evaluated using the Log-rank test. P values less than 0.05 were considered satistically significant. Analyses were performed with SPSS software v.15. Results: Median age was 64 years (range 36–88); median haemoglobin was 110 g/l (range, 60–157) and 48,1% patients had a transfusion-dependent anemia. Median platelet an leucocyte counts were respectively 311 × 109/l (range, 52–1887) and 14,8 × 109/l (range, 52–1887). 54,5% patients have a PMF diagnosis. JAK2V617F was present in 69,8% patients, CALR mutations in 15,4% and MPLW515K/L in 5,3%; 9,5%of the patients were triple negatives. Leucocytes <15x10e9/ and JAK2V617F were correlated with better survival. At the moment of diagnosis, 32,7% of patients were older than 70 years. In this group, the median of survival from the diagnosis was 70 months. Causes of death were, specifically: progression of myelofibrosis (22,2%), evolution into acute leukemia (22,2%), second neoplasias (22,2%), heart disease (33,3%). Summary/Conclusion: 1.-Elderly patients in our group treated with ruxolitinib have a median survival of 70 months which is a clear advantage with respect to historic cohorts of MF. 2.-Ruxolitinib was well tolerated but does not avoid clonal evolution and JAK1 inhibition could worsen tumor inmmunosurveillance.