When Ruxolitinib Fails in Myelofibrosis with Bulky Splenomegaly or Disease Symptoms
This protocol covers low-risk or intermediate-1 risk primary myelofibrosis presenting with disease-related symptoms or significantly enlarged spleen, where first-line treatment has not delivered an adequate response.
Low-risk or intermediate-1 risk myelofibrosis with symptomatic disease burden or bulky splenomegaly. Controlling spleen size and reducing symptom burden are the primary clinical objectives at this stage.
First-line treatment with the JAK inhibitor ruxolitinib did not achieve the required response thresholds: at least a 10% reduction in spleen volume, or a 50% reduction in symptom burden, by approximately 8 weeks. Resistance to or intolerance of ruxolitinib triggers escalation to this next-line protocol.
The next step centres on switching to an alternative oral JAK inhibitor indicated specifically for patients who are resistant to or intolerant of ruxolitinib. Agent selection and eligibility are guided by individual patient factors detailed in the full protocol — including baseline blood counts and prior response characteristics.
References
- Low risk
- Intermediate 1
- Symptomatic/ bulky spleen
- Fedratinib is an oral JAK2 inhibitor recommended in the United Kingdom for the treatment of disease-related symptoms or splenomegaly in adults with MF who are resistant to or intolerant of ruxolitinib.
- Recommended initial dosing of fedratinib is 400 mg once daily for patients with a baseline platelet count ≥50 × 10⁹/L.
- The starting dose of 200 mg is fixed, irrespective of baseline platelet count and ability to maintain dose is frequently very stable.