Myeloproliferative neoplasms (MPNs) are uncommon in children and young people. As a result, the guidelines currently used to reduce the risk of thrombosis and hemorrhage in patients with MPNs are based on literature involving patients over the age of 60.

A team of researchers set out to learn more about children and young adults with MPNs, due to the lack of sparse existing data. They published their findings in Blood Advances.

The researchers conducted a retrospective study that included members of the European Hematology Association MPN scientific working group who were diagnosed with an MPN before the age of 25. They examined data from 444 patients from 15 countries, 53.8% of who were diagnosed between the ages of 20 and 25.

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They confirmed that the most common MPN subtype was essential thrombocythemia (ET), representing 71.6% of this cohort. Another 18.2% had the polycythemia vera (PV) subtype, and the remaining had primary myelofibrosis (PMF), prefibrotic myelofibrosis (PreMF), or unclassified MPN (MPN-u).

They also found what they called “interesting perspectives on how these MPN are perceived by physicians” and how they are managed. “Importantly, we demonstrate that standard prognostic scores do not perform well in this cohort,” they wrote. “As an example, 67.8% received at least one cytoreductive drug when only 21.4% of them should have received such therapy according to currently [European LeukemiaNet (ELN)] recommendations.”

They added that the proportion of certain prescriptions for the participants also suggested that their physicians didn’t apply ELN recommendations “where interferon is the recommended first-line therapy in patients aged below 60 years old because of its lack of leukemogenicity  and its low teratogenicity.” But as they noted, no MPN guidelines exist for children or adolescents, so the differences likely reflect “historical shifts in guidelines and availability of therapy.”

The researchers also uncovered higher-than-anticipated rates of thrombosis, hemorrhage, and transformation in their real-world cohort compared with the rates in their literature review. And 11% of patients had a history of thrombotic events, especially in patients with PV (21.5%).

“Due to the predominance of venous events, classical management with low-dose aspirin to prevent thrombosis should perhaps be questioned in this specific population, as it mainly reduces the risk of arterial events,” the researchers wrote. “The use of anticoagulants could be a way to reduce the incidence of venous thrombotic events.”

The study did have limitations, such as its retrospective nature, which may have resulted in some biases. Also, without specific treatment guidelines for young patients, the management could have been heterogeneous among the various centers, which could have influenced the rate of complications. However, they did point out that they had a “very high number of such extremely rare patients….suggesting that we revealed a reliable picture of MPN in very young patients.”

Ultimately, the research revealed a high disease burden with incidences of thrombotic events and transformations that were higher than previously reported in this particular population. The information could be used for future biomarkers studies, clinical trials, and the creation specific treatment guidelines for younger MPN patients.

Disclosures: Some authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Sobas M, Kiladjian J, Beauverd Y, et al. Real world study of children and young adults with myeloproliferative neoplasms identifying risks and unmet needs. Blood Adv. Published online July 8, 2022. doi:10.1182/bloodadvances.2022007201