MPN-355 Patients With Prefibrotic Myelofibrosis and Inferior Outcome, a Single-Center Analysis.

Abstract

The 2016 WHO classification distinguishes prefibrotic primary myelofibrosis (pre-PMF) as a separate entity from overt MF, with less marrow fibrosis (only grade 0-1) and more favorable survival. To characterize pre-PMF patients referred to our institution between 2000 and 2020 and identify patients with the worst outcomes. A retrospective study of 130 newly diagnosed pre-PMF patients with available marrow fibrosis grading. IPSS scores and individual factors used in IPSS scoring were annotated (Cervantes et al. Blood. 2009), Main Outcomes: Overall survival (OS) of patients according to IPSS risks and the presence of individual IPSS risk factors: i) hemoglobin < 10 g/dL; ii) WBC >25×109/L; and iii) peripheral blasts ≥1%, in the context of age >65 years and ± systemic symptoms (Kaplan-Meier analysis with log-rank test). The majority of patients had grade 1 fibrosis (88%). A total of 58 patients (45%) had intermediate, 2, or high-risk IPSS. No, one, and two individual IPSS risk factors (i-ii) were identified in 27%, 24%, and 11% of patients, respectively, but 38% had symptoms. Median OS (95% CI) for the entire cohort was 68 months (42-94 months); for IPSS low-ntermediate was not reached; for IPSS 1 was 179 months (65-not expressed); for IPSS 2 was 65 months (32-98 months), and for IPSS high was 27 months (5-49 months). Median OS (95% CI) for patients without risk factors ± symptoms was not reached. Median OS for patients with one risk factor ± symptoms was 48 months (33-63 months), whereas median OS for patients with two risk factors was 16 months (8-24 months). Forty-one percent of patients required disease=directed therapy (JAK inhibitors in 37, stem cell transplantation in 8). Patients without the need for therapy or those who received JAK inhibitors had superior median OS (range 81-100 months) over treated patients without exposure to JAK inhibitors (median OS of 45 months). About 20% of patients with pre-PMF have poor outcomes, with median OS < 3 years. The use of JAK inhibitor improves outcomes among symptomatic patients in need of therapy.