Determinants of survival and retrospective comparisons of 183 clinical trial patients with myelofibrosis treated with momelotinib, ruxolitinib, fedratinib or BMS- 911543 JAK2 inhibitor
Naseema Gangat, Kebede H. Begna, Aref Al‐Kali, William J. Hogan, Mark R. Litzow, Animesh Pardanani, Ayalew Tefferi
Abstract
Between October 2007 and July 2013, 183 Mayo Clinic patients (median age 65 years; 58% males) with high/intermediate risk myelofibrosis (MF) were enrolled in consecutive phase 1/2 JAK2 inhibitor (JAKi) clinical trials with momelotinib (n = 79), ruxolitinib (n = 50), fedratinib (n = 23) and BMS-911543 (n = 31). Using conventional criteria, the respective response rates for spleen and "transfusion-dependent anemia" were 47%, 32%, 83%, 62% and 51%, 30%, 10%, 44%, respectively, favoring momelotinib for anemia response (p = 0.02) and fedratinib for spleen response (p < 0.01). All study patients were followed to death or 2022, during which time 177 (97%) drug discontinuations, 27 (15%) leukemic transformations, and 22 (12%) allogeneic stem cell transplants (ASCT) were recorded. 5/10-year survival rate for all 183 patients was 41%/16% and not significantly different across the four drug cohorts (p = 0.33). Multivariable analysis of pre-treatment variables identified age >65 years (HR 3.5), absence of type 1/like CALR mutation (HR 2.8), baseline transfusion need (HR 2.1), and presence of ASXL1/SRSF2 mutation (HR 1.6) as risk factors for overall survival; subsequent HR-based modeling segregated three risk categories with 5/10-year survival rates of 84%/60%, 44%/14%, and 21%/5% (p < 0.01). In addition, spleen (p < 0.01) and anemia (p = 0.01) responses were independently associated with improved short-term survival while long-term survival was secured only by ASCT (5/10-year survival rate 91%/45% vs 47%/19% in non-transplanted patients; p < 0.01). The current retrospective study suggests the value of specific pre-treatment variables in identifying long-lived MF patients receiving JAKi and also confirms recent observations on the favorable impact of treatment response on short-term and of ASCT on long-term survival.