Overview
Primary myelofibrosis (PMF), also known as idiopathic myelofibrosis, agnogenic myeloid metaplasia, or chronic idiopathic myelofibrosis, is a rare and serious bone marrow disorder. In PMF, scar tissue (fibrosis) gradually builds up inside the bone marrow — the spongy tissue inside your bones where blood cells are made. As scar tissue replaces healthy marrow, the bone marrow can no longer produce enough normal blood cells. To compensate, the spleen and liver try to take over blood cell production, which causes these organs to become enlarged. PMF belongs to a group of blood cancers called myeloproliferative neoplasms (MPNs). It develops when certain blood stem cells develop mutations (changes in their DNA) that cause them to grow and divide in an uncontrolled way. The most common mutations involved are in the JAK2, CALR, and MPL genes. Over time, the abnormal cells crowd out healthy ones, leading to low red blood cell counts (anemia), abnormal white blood cell and platelet levels, and a range of difficult symptoms. Symptoms can include extreme fatigue, a swollen and painful abdomen due to an enlarged spleen, night sweats, fever, unintended weight loss, and bone pain. Some people are diagnosed before symptoms appear, while others have significant illness at diagnosis. Treatment ranges from watchful waiting in mild cases to targeted drugs like ruxolitinib (Jakafi) and fedratinib (Inrebic), and in eligible patients, a stem cell transplant — the only potentially curative option. Research into new therapies is very active.
Also known as:
Key symptoms:
Extreme tiredness and fatigue that does not improve with restEnlarged spleen causing a feeling of fullness, discomfort, or pain in the upper left abdomenEnlarged liverUnintended weight lossNight sweatsFever without an obvious infectionBone or joint painPale skin due to anemia (low red blood cell count)Shortness of breath, especially with activityEasy bruising or bleedingFeeling full quickly when eating (due to enlarged spleen pressing on the stomach)Itching, especially after a warm bath or showerFrequent infections due to abnormal white blood cells
Clinical phenotype terms (36)— hover any for plain English
Sporadic
Usually appears on its own, not inherited from a parent
Adult
Begins in adulthood (age 18 or older)
FDA & Trial Timeline
10 eventsUnited Lincolnshire Hospitals NHS Trust — PHASE2
SWOG Cancer Research Network — PHASE4
Chia Tai Tianqing Pharmaceutical Group Co., Ltd. — PHASE1
Washington University School of Medicine — PHASE1
Institute of Hematology & Blood Diseases Hospital, China — PHASE2
Grupo Español de Enfermedades Mieloproliferativas Crónicas PH Negativas — PHASE2
Massachusetts General Hospital — PHASE1
Chengdu Zenitar Biomedical Technology Co., Ltd — PHASE3
M.D. Anderson Cancer Center — PHASE1, PHASE2
Gruppo Italiano Malattie EMatologiche dell'Adulto
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
3 availableInrebic
indicated for the treatment of adult patients with intermediate-2 or high-risk primary myelofibrosis (MF)
Ojjaara
indicated for the treatment of intermediate or high-risk myelofibrosis (MF), including primary MF or secondary MF [post-polycythemia vera (PV) and post-essential thrombocythemia (ET)], in adults with …
indicated for the treatment of intermediate or high-risk myelofibrosis (MF), including primary MF or secondary MF [post-polycythemia vera (PV) and post-essential thrombocythemia (ET)], in adults with anemia
Vonjo
indicated for the treatment of adults with intermediate or high-risk primary myelofibrosis (MF) with a platelet count below 50 × 10 9 /L
Rare Disease Specialist
Treatment Centers
8 centersJohns Hopkins University
📍 Baltimore, Maryland
Rush University Medical Center
📍 Chicago, Illinois
City of Hope
📍 Duarte, California
Mayo Clinic Hospital
📍 Phoenix, Arizona
Yale School of Medicine
📍 New Haven, Connecticut
👤 Sara Pai
USC Norris Comprehensive Cancer Center
📍 Los Angeles, California
👤 Janssen Research & Development, LLC Clinical Trial
Harvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
Financial Resources
3 resourcesTravel Grants
No travel grants are currently matched to Primary myelofibrosis.
Community
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1 articlesCaregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What is my risk category, and what does that mean for my treatment and outlook?,Which genetic mutations do I have, and how do they affect my prognosis or treatment options?,Am I a candidate for a stem cell transplant now or in the future?,Which medication is right for me, and what side effects should I watch for?,How often do I need blood tests and bone marrow biopsies to monitor my disease?,Are there any clinical trials I should consider?,What symptoms should prompt me to call you or go to the emergency room right away?
Common questions about Primary myelofibrosis
What is Primary myelofibrosis?
Primary myelofibrosis (PMF), also known as idiopathic myelofibrosis, agnogenic myeloid metaplasia, or chronic idiopathic myelofibrosis, is a rare and serious bone marrow disorder. In PMF, scar tissue (fibrosis) gradually builds up inside the bone marrow — the spongy tissue inside your bones where blood cells are made. As scar tissue replaces healthy marrow, the bone marrow can no longer produce enough normal blood cells. To compensate, the spleen and liver try to take over blood cell production, which causes these organs to become enlarged. PMF belongs to a group of blood cancers called myelo
How is Primary myelofibrosis inherited?
Primary myelofibrosis follows a sporadic inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Primary myelofibrosis typically begin?
Typical onset of Primary myelofibrosis is adult. Age of onset can vary across affected individuals.
Are there clinical trials for Primary myelofibrosis?
Yes — 20 recruiting clinical trials are currently listed for Primary myelofibrosis on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Primary myelofibrosis?
25 specialists and care centers treating Primary myelofibrosis are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.