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9 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Primary myelofibrosis is a blood cancer in which the marrow scars over, the spleen swells and patients become anaemic and exhausted. JAK inhibitors, ruxolitinib first (COMFORT) and then fedratinib, pacritinib and momelotinib (MOMENTUM), shrink the spleen and relieve symptoms; only a donor stem cell transplant can cure it.
Primary myelofibrosis arises from a haematopoietic stem cell carrying JAK2 V617F (about 60 percent), CALR (about 25 percent) or MPL (5 to 8 percent), or none of the three (triple negative, the worst group), with additional high-risk mutations in ASXL1, SRSF2, EZH2, IDH1/2 and U2AF1. The clone drives cytokine release and megakaryocyte abnormalities that scar the marrow; blood production moves to the spleen and liver, which enlarge, and patients develop anaemia, constitutional symptoms, early satiety and bone pain. A prefibrotic phase resembles essential thrombocythaemia. Risk scores (IPSS, DIPSS-plus, MIPSS70 and MIPSS70-plus v2 with mutations and cytogenetics) predict survival and steer the transplant decision; about one in five progress to blast phase, for which no treatment reliably works.
JAK inhibitors treat the disease's consequences. Ruxolitinib, the first, shrank the spleen by 35 percent or more in 41.9 percent of patients against 0.7 percent on placebo at 24 weeks in COMFORT-I (2012), and beat best available therapy in COMFORT-II, with symptom scores halving in nearly half; approval came in 2011 and a survival advantage emerged in pooled long-term data. Fedratinib (JAKARTA, 2019 approval) works after ruxolitinib failure but carries a warning for Wernicke encephalopathy; pacritinib (PERSIST-2, approved 2022) is the option when platelets fall below 50 x 10^9/L; and momelotinib, which also blocks ACVR1 and so raises haemoglobin, was approved in 2023 after MOMENTUM, in which 25 percent of anaemic, previously treated patients had their symptom score halve against 9 percent on danazol, with more becoming transfusion independent. None of them clears the clone.
| Setting | Approach | Guideline |
|---|---|---|
| Lower-risk, asymptomatic | Observation; aspirin for thrombosis risk where platelets are high; hydroxyurea or interferon for proliferative features. | not mapped |
| Symptomatic splenomegaly or constitutional symptoms | Ruxolitinib (COMFORT-I and II) first; fedratinib after ruxolitinib failure or intolerance; pacritinib if platelets are below 50 x 10^9/L; momelotinib if anaemic. | not mapped |
| Anaemia of myelofibrosis | Momelotinib (MOMENTUM), erythropoiesis-stimulating agents where erythropoietin is low, danazol, transfusion with iron chelation; luspatercept in trials (INDEPENDENCE). | not mapped |
| Higher-risk, fit for transplant | Allogeneic stem cell transplant, usually under 70 and at MIPSS70 high or DIPSS intermediate-2 or higher, after JAK inhibitor to reduce spleen size. | not mapped |
| Ruxolitinib failure and trials | Switch JAK inhibitor; combination trials of ruxolitinib with navitoclax, pelabresib, selinexor or imetelstat; imetelstat versus best available therapy in IMpactMF. | not mapped |