June 14, 2024
Author(s): Sabrina Serani
Among patients with low- or intermediate-risk myelofibrosis (MF), a majority were reported to have disease progression over 4 years, and the rate of progression increased over time, according to findings from the prospective observational MOST study (NCT02953704) presented in a poster session at the 2024 EHA Congress. These findings provide important insight into the rates of disease progression for patients with lower-risk MF, a patient group with limited prospective data available on this topic.
A total of 232 patients with MF were enrolled, with 205 patients considered low or INT-1 risk due to being aged over 65 years alone comprising cohort A and 27 patients considered low or INT-1 risk for factors other than age only being evaluated in cohort B. In cohort A, 58.5% (n = 120) of patients experienced disease progression during the study, with the most common progression criteria being hemoglobin below 10 g/dL (47.5%). Further, 12 patients (10.0%) died due to disease progression and 6 (5%) had leukemic transformation. In cohort B, 29.6% (n = 8) of patients had disease progression during the course of the study.
Laboratory-defined criteria for progression in the MOST study included hemoglobin below 10 g/dL, platelet count below 100 × 109/L, less than 1% blasts, white blood cell count above 25 × 109/L, and leukemic transformation with greater than 20% blasts. Physician-reported criteria for progression were constitutional symptoms (weight loss, fever, sweats), new or worsening splenomegaly, 1 red blood cell transfusion during the study, physician-reported leukemic transformation, and death due to disease progression. The presence of at least 1 criterion was considered disease progression.