According to research presented at the 2024 American Society of Clinical Oncology (ASCO) annual meeting, cytopenias and/or proliferation, rather than JAK2V617F (JAK2) allele burden </≥50%, correlate with the outcomes of patients with primary myelofibrosis (PMF) and patients with MF from essential thrombocythemia or polycythemia vera (PPV/PET-MF). In addition, all patients were noted to display improved survival with ruxolitinib treatment.
Myelodepleted MF, which is characterized by cytopenias, lower JAK2 allele burden, and shorter benefit from JAK-inhibitor ruxolitinib, exhibits worse overall survival (OS) compared to myeloproliferative MF. In addition, lower JAK2 and inferior OS is generally more typical for patients with primary MF (PMF) as compared with patients with MF from essential thrombocythemia or polycythemia vera (PPV/PET-MF).
“We sought to investigate the impact of JAK2 (</≥ 50%), cytopenias and the use of ruxolitinib in outcome of PMF/PPV-PET-MF patients from our center,” explained Julie Braish, MBBCh, The University of Texas MD Anderson Cancer Center, Houston, Texas and colleagues.
To determine these results, study authors retrospectively reviewed the medical charts of 601 patients with JAK2-mutated MF (known JAK2%). Patients were divided based on the absence (-) or presence (+) of cytopenias (hemoglobin < 10 g/dL or platelets < 100 x109/L) and leukocytosis (WBC ≥ 25 x109/L) into: grade 1 = (-)/(-) [absence of both]; grade 2 = (-)/(+) [proliferative]; grade 3 = (+)/(-) [cytopenic]; grade 4 = (+)/(+) [cytopenic and proliferative]) and evaluated overall survival (OS) per JAK2 </≥ 50% and PMF vs PPV/PET-MF. Investigators assessed the tolerance of ruxolitinib ≥3 years by utilizing descriptive statistics, Kaplan-Meier curve with log-rank test and regression analysis for demographics, estimation of OS and its comparison.