Primary Myelofibrosis Survival Improving Except for Poor-Risk Patients
“This observation must be taken into account at the time of evaluating the survival impact of newer therapies for primary myelofibrosis, which are currently being tested in these patient subpopulations,” noted Francisco Cervantes, MD, Hospital Clínic, Barcelona, Spain, and colleagues.
Previously, median survival of primary myelofibrosis has been estimated to range from 3.5 to 5 years. In this study, 802 patients diagnosed with primary myelofibrosis from France, Italy, Spain, and the United Kingdom were compared for presentation of features and survival from 1980–1995 (n=434) and 1996–2007 (n=368).
Compared with the earlier time period, those who were diagnosed with primary myelofibrosis between 1996 and 2007 more often experienced constitutional symptoms (31% vs 23%) but had a lower incidence of marked anemia (31% vs 39%), leukocytosis >25 x 109/L (9% vs 13%), and blood blasts (27% vs 33%). Distribution of risk was comparable between the two groups.
Median survival was 4.6 years (95% CI, 4.0–5.1) for patients from 1980–1995 and 6.5 years (95% CI, 5.5–7.4) for patients from 1996 to 2007 (P<0.001). In the later time period, “patients showed improved relative survival, especially for women, patients younger than age 65 years, and patients with low or intermediate-1–risk disease,” the investigators reported.
At 5 and 10 years, rates of primary myelofibrosis-attributable mortality years were significantly lower in the later time period; this reduction in disease occurred across all patient subgroups, except in intermediate-2–risk or high-risk patients.
“In conclusion, this study shows that, although primary myelofibrosis survival is steadily improving, this is not the case for patients in poor-risk categories of the disease. This finding should stimulate the search for better treatment modalities for poor-risk patients and must be taken into account at the time of evaluating the survival impact of newer therapies for primary myelofibrosis, such as JAK2 inhibitors, that are usually prescribed to patients in unfavorable-risk categories,” they wrote.