A group of researchers presented data on disease progression for patients with low-risk myelofibrosis (MF) participating in the prospective observational Myelofibrosis and Essential Thrombocythemia Observational Study (MOST) at the 2023 ASH Annual Meeting & Exposition.
In order to qualify for the MOST study, participants were required to have a physician-reported diagnosis of MF (primary myelofibrosis [PMF], post progression of polycythemia vera [post-PV], or post essential thrombocythemia [post-ET). They also could not have any risk factors per the Dynamic International Prognostic Scoring System (DIPSS) criteria. However, participants could be aged 65 years or older. The number of patients with MF enrolled in the study was 232. Of this population, 205 met the study criteria and were included in cohort A. Although the remaining 27 patients had ≥1 DIPSS risk factor, they were included in the study in a separate cohort B.
For the study, disease progression was defined by the worsening of clinical or laboratory parameters, which included one or more of the following criteria: hemoglobin (Hb) <10 g/dL, platelets <100×109/L, presence of constitutional symptoms (weight loss, fever, or sweats), new or worsening splenomegaly, blasts >1%, white blood cell count >25×109/L, death due to disease progression, leukemic transformation (LT), or >1 red blood cell transfusion. The median follow-up was 52.9 months (42-68).