Pediatric Myelofibrosis Treatment & Management

Updated: Nov 16, 2018
  • Author: Trisha Simone Natanya Tavares, MD; Chief Editor: Robert J Arceci, MD, PhD  more...
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Treatment

Approach Considerations

Treatment should be directed at the underlying process when secondary childhood myelofibrosis is identified.

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Supportive Care and Monitoring

Supportive care of myelofibrosis with transfusions (red blood cells [RBCs], platelets) is crucial to short-term management. Blood products should be leukodepleted (to decrease the likelihood of human leukocyte antigen [HLA] sensitization) and, ideally, cytomegalovirus (CMV) negative.

Prophylaxis against opportunistic infections (eg, fluconazole) may be indicated for some patients with neutropenia. Aggressive treatment of fever and suspected infections is also important.

Intravenous immunoglobulin and bisphosphonates may be useful in selected cases. An 8-month-old girl with myelofibrosis and dysgranulopoiesis responded to intravenous immunoglobulin (added to previous corticosteroid therapy). [38] Her disease was unusual and was characterized by a positive Coombs test result and antineutrophil antibodies, suggesting an autoimmune etiology.

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Pharmacotherapy

Corticosteroids

In pediatric patients, high-dose glucocorticoid therapy may ameliorate marrow fibrosis and improve hematopoieses. [11, 28, 39, 40]

Interferon-alfa

Interferon-alfa has been useful for treatment of splenic enlargement, bone pain, and thrombocytosis, including in pediatric patients. Interferon-alfa and interferon-gamma act together to inhibit myeloproliferation. [11, 41]

Hydroxyurea

Hydroxyurea is one of the most commonly used agents in the management of this condition. It has been shown to decrease spleen size and reduce constitutional symptoms. Improvement in peripheral blood cell counts and bone marrow fibrosis are also seen.

Thalidomide and lenalidomide

These antiangiogenic agents are used to reduce transfusion requirements and decrease spleen size. These medications are believed to down-regulate the proinflammatory response. They may be used in combination with glucocorticoids. [42, 43, 44]

Vitamin D

Myelofibrosis is observed in some patients with severe vitamin D deficiency. In addition, cases of myelofibrosis associated with essential thrombocythemia or myelomonocytic leukemia, as well as acute (idiopathic) myelofibrosis (IMF), have responded to vitamin D administration. [45, 46]

Decitabine

Decitabine, an S-phase–specific inhibitor of deoxyribonucleic acid (DNA) methyltransferase, has shown promise in adult patients with myelofibrosis. [47] Pediatric dosing for this drug has not been established, and no literature regarding its use in children with myelofibrosis has been published.

Janus kinase inhibitors

Ruxolitinib is an orally bioavailable, selective JAK1 and JAK2 inhibitor approved for the treatment of myelofibrosis. Other JAK inhibitors with similar clinical profiles are in clinical development but have yet to be approved for therapeutic use. [48]  

In June 2013, the US Food and Drug Administration (FDA) updated the prescribing information for ruxolitinib to include new recommended dosing for patients with low platelet counts and a warning about a possible treatment-related risk for progressive multifocal leukoencephalopathy (PML). [49]  For patients with baseline platelet counts of 50-100 × 10⁹/L (50,000-100,000/µL), the updated prescribing information recommended a starting dosage of 5 mg twice daily and the flexibility for subsequent dosage modifications based on safety and efficacy. [49] Additionally, healthcare professionals were advised to educate patients regarding early signs and symptoms of PML.

Results from a phase 3 trial indicated that pacritinib, which inhibits JAK2 and FMS-like tyrosine kinase-3 (FLT3), is not only effective against myelofibrosis but is safer than ruxolitinib for use in patients with a low platelet count. The trial involved 327 patients. [50, 51]

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Radiotherapy

Radiotherapy has been offered to patients with painful massive splenomegaly who are not surgical candidates. This treatment should be used sparingly, however, as it may worsen cytopenias. Radiation therapy has also been used for palliation of bony lesions, ascites, and other mass lesions.

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Hematopoietic Stem Cell Transplantation

In a 2009 report from Tennessee, 2 children with infantile myelofibrosis were successfully treated with unrelated hematopoietic stem cell transplantation. [52]

Bone marrow transplantation is the only potential cure to primary myelofibrosis. Patients with a matched sibling donor with a poor prognosis should be evaluated for transplantation.

A retrospective analysis of 203 adult patients with myelofibrosis suggested, in contrast to earlier reports, that myelofibrosis has little adverse effect on engraftment following allogeneic hematopoietic cell transplant. [53]

Allogeneic bone marrow transplantation has been used successfully to treat patients with myelofibrosis. [54, 55] Preparative regimens and donors varied. Nonmyeloablative conditioning is appropriate in certain patients.

Published experience from Sweden and Germany demonstrated that reduced-intensity preparative regimens are often effective for treating myelofibrosis and clearly have less treatment-related mortality than do myeloablative regimens. [56, 57]

Donor lymphocyte infusion in posttransplanted patients can be used to cause regression of fibrosis in patients with evidence of relapse.

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Splenectomy

Patient selection for spleen removal is controversial. [58] Transfusion-dependent anemia, portal hypertension, and/or symptoms of hypercatabolism are potential indications for splenectomy, but the surgery-related mortality rate may be significant. [59]

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