Diagnosis of Myelofibrosis (MF)

Diagnostic criteria for primary MF (PMF)

Diagnosis of PMF may be performed using criteria developed by the World Health Organization (WHO). Diagnostic criteria are divided into major criteria and minor criteria, with a requirement for the number of each type that must be present to make the diagnosis.

Major diagnostic criteria for PMF include:
  • proliferation and atypia of megakaryocytes accompanied by either reticulin and/or collagen fibrosis,
  • not meeting WHO criteria for other myeloid malignancies, and
  • presence of specific mutations including JAK2
Minor diagnostic criteria include:
  • anemia not attributed to a comorbid condition,
  • leukocytosis,
  • palpable splenomegaly,
  • increased lactate dehydrogenase (LDH), and
  • leukoerythroblastosis

Diagnosis of PMF requires meeting all 3 major criteria, and at least 1 minor criterion (confirmed in 2 consecutive determinations).1

The presence or absence of the JAK2V617F mutation does not independently determine the diagnosis of myelofibrosis.1

Click on the table for a downloadable, printable diagnostic worksheet that may be used to help assess patients for MF according to the WHO Guidelines.

World Health Organization (WHO) Diagnostic Criteria for PMF1 Image of Primary Myelofibrosis (PMF) diagnosis criteria

Diagnostic criteria for post–polycythemia vera MF (post–PV MF) and post–essential thrombocythemia MF (post–ET MF)2

Polycythemia vera and essential thrombocythemia may progress to myelofibrosis. The estimated rates of progression are:

  • PV to post–PV MF: 10% in 10 years2
  • ET to post–ET MF: <4% in 10 years2

International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) criteria, shown in the table at the right, are used for diagnosis of post–PV MF and post–ET MF. Check off the major and minor criteria corresponding to the patient’s clinical presentation. Use only the unshaded boxes. Add the checkmarks in each column and compare the result against the totals required to meet IWG-MRT guidelines for diagnosis of post–PV MF and post–ET MF.3

Image of Mean Diagnosis of post-polycythemia vera MF (post-PV MF) and post-essential thrombocythemia MF (post-ET MF)
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Expand References +
  • Arber DA, Orazi A, Hasserjian R, et al. Blood. 2016;127(20):2391-2405.
  • Tefferi A. Am J Hematol. 2008:83:491-497.
  • Barosi G, Mesa RA, Thiele J, et al; International Working Group for Myelofibrosis Research and Treatment (IWG-MRT). Leukemia. 2008;22:437-438.

INDICATIONS AND USAGE

Jakafi is indicated for treatment of patients with polycythemia vera who have had an inadequate response to or are intolerant of hydroxyurea.

Jakafi is indicated for treatment of patients with intermediate or high-risk myelofibrosis (MF), including primary MF, post–polycythemia vera MF and post–essential thrombocythemia MF.

IMPORTANT SAFETY INFORMATION

  • Treatment with Jakafi® (ruxolitinib) can cause thrombocytopenia, anemia and neutropenia, which are each dose‐related effects. Perform a pre‐treatment complete blood count (CBC) and monitor CBCs every 2 to 4 weeks until doses are stabilized, and then as clinically indicated
  • Manage thrombocytopenia by reducing the dose or temporarily interrupting Jakafi. Platelet transfusions may be necessary
  • Patients developing anemia may require blood transfusions and/or dose modifications of Jakafi
  • Severe neutropenia (ANC <0.5 x 109/L) was generally reversible by withholding Jakafi until recovery
  • Serious bacterial, mycobacterial, fungal and viral infections have occurred. Delay starting Jakafi until active serious infections have resolved. Observe patients receiving Jakafi for signs and symptoms of infection and manage promptly
  • Tuberculosis (TB) infection has been reported. Observe patients taking Jakafi for signs and symptoms of active TB and manage promptly. Prior to initiating Jakafi, evaluate patients for TB risk factors and test those at higher risk for latent infection. Consult a physician with expertise in the treatment of TB before starting Jakafi in patients with evidence of active or latent TB. Continuation of Jakafi during treatment of active TB should be based on the overall risk‐benefit determination
  • Progressive multifocal leukoencephalopathy (PML) has occurred with Jakafi treatment. If PML is suspected, stop Jakafi and evaluate
  • Advise patients about early signs and symptoms of herpes zoster and to seek early treatment
  • Increases in hepatitis B viral load with or without associated elevations in alanine aminotransferase and aspartate aminotransferase have been reported in patients with chronic hepatitis B virus (HBV) infections. Monitor and treat patients with chronic HBV infection according to clinical guidelines
  • When discontinuing Jakafi, myeloproliferative neoplasm-related symptoms may return within one week. After discontinuation, some patients with myelofibrosis have experienced fever, respiratory distress, hypotension, DIC, or multi‐organ failure. If any of these occur after discontinuation or while tapering Jakafi, evaluate and treat any intercurrent illness and consider restarting or increasing the dose of Jakafi. Instruct patients not to interrupt or discontinue Jakafi without consulting their physician. When discontinuing or interrupting Jakafi for reasons other than thrombocytopenia or neutropenia, consider gradual tapering rather than abrupt discontinuation
  • Non‐melanoma skin cancers including basal cell, squamous cell, and Merkel cell carcinoma have occurred. Perform periodic skin examinations
  • Treatment with Jakafi has been associated with increases in total cholesterol, low-density lipoprotein cholesterol, and triglycerides. Assess lipid parameters 8-12 weeks after initiating Jakafi. Monitor and treat according to clinical guidelines for the management of hyperlipidemia
  • The three most frequent non‐hematologic adverse reactions (incidence >10%) were bruising, dizziness and headache
  • A dose modification is recommended when administering Jakafi with strong CYP3A4 inhibitors or fluconazole or in patients with renal or hepatic impairment. Patients should be closely monitored and the dose titrated based on safety and efficacy
  • Use of Jakafi during pregnancy is not recommended and should only be used if the potential benefit justifies the potential risk to the fetus. Women taking Jakafi should not breastfeed during treatment and for two weeks after the final dose

Please see Full Prescribing Information for Jakafi.

 
IMPORTANT SAFETY INFORMATION
 
INDICATIONS AND USAGE
Jakafi is indicated for treatment of patients with polycythemia vera who have had an inadequate response to or are intolerant of hydroxyurea.

Jakafi is indicated for treatment of patients with intermediate or high-risk myelofibrosis (MF), including primary MF, post–polycythemia vera MF and post–essential thrombocythemia MF.
IMPORTANT SAFETY INFORMATION
  • Treatment with Jakafi® (ruxolitinib) can cause thrombocytopenia, anemia and neutropenia, which are each dose‐related effects. Perform a pre‐treatment complete blood count (CBC) and monitor CBCs every 2 to 4 weeks until doses are stabilized, and then as clinically indicated
  • Manage thrombocytopenia by reducing the dose or temporarily interrupting Jakafi. Platelet transfusions may be necessary
  • Patients developing anemia may require blood transfusions and/or dose modifications of Jakafi
  • Severe neutropenia (ANC <0.5 x 109/L) was generally reversible by withholding Jakafi until recovery
  • Serious bacterial, mycobacterial, fungal and viral infections have occurred. Delay starting Jakafi until active serious infections have resolved. Observe patients receiving Jakafi for signs and symptoms of infection and manage promptly
  • Tuberculosis (TB) infection has been reported. Observe patients taking Jakafi for signs and symptoms of active TB and manage promptly. Prior to initiating Jakafi, evaluate patients for TB risk factors and test those at higher risk for latent infection. Consult a physician with expertise in the treatment of TB before starting Jakafi in patients with evidence of active or latent TB. Continuation of Jakafi during treatment of active TB should be based on the overall risk‐benefit determination
  • Progressive multifocal leukoencephalopathy (PML) has occurred with Jakafi treatment. If PML is suspected, stop Jakafi and evaluate
  • Advise patients about early signs and symptoms of herpes zoster and to seek early treatment
  • Increases in hepatitis B viral load with or without associated elevations in alanine aminotransferase and aspartate aminotransferase have been reported in patients with chronic hepatitis B virus (HBV) infections. Monitor and treat patients with chronic HBV infection according to clinical guidelines
  • When discontinuing Jakafi, myeloproliferative neoplasm-related symptoms may return within one week. After discontinuation, some patients with myelofibrosis have experienced fever, respiratory distress, hypotension, DIC, or multi‐organ failure. If any of these occur after discontinuation or while tapering Jakafi, evaluate and treat any intercurrent illness and consider restarting or increasing the dose of Jakafi. Instruct patients not to interrupt or discontinue Jakafi without consulting their physician. When discontinuing or interrupting Jakafi for reasons other than thrombocytopenia or neutropenia, consider gradual tapering rather than abrupt discontinuation
  • Non‐melanoma skin cancers including basal cell, squamous cell, and Merkel cell carcinoma have occurred. Perform periodic skin examinations
  • Treatment with Jakafi has been associated with increases in total cholesterol, low-density lipoprotein cholesterol, and triglycerides. Assess lipid parameters 8-12 weeks after initiating Jakafi. Monitor and treat according to clinical guidelines for the management of hyperlipidemia
  • The three most frequent non‐hematologic adverse reactions (incidence >10%) were bruising, dizziness and headache
  • A dose modification is recommended when administering Jakafi with strong CYP3A4 inhibitors or fluconazole or in patients with renal or hepatic impairment. Patients should be closely monitored and the dose titrated based on safety and efficacy
  • Use of Jakafi during pregnancy is not recommended and should only be used if the potential benefit justifies the potential risk to the fetus. Women taking Jakafi should not breastfeed during treatment and for two weeks after the final dose

Please see Full Prescribing Information for Jakafi.