JUMP trial: A post hoc analysis of ruxolitinib and anemia-supporting medications in patients with MF

Anemia is a common and often severe complication of myelofibrosis (MF). Treatment with Janus kinase (JAK) inhibitors, such as ruxolitinib, can result in dose-dependent anemia in patients with MF, which affects treatment decisions. The recommended treatments for managing anemia include erythropoiesis-stimulating agents (ESAs) and danazol. However, there is a lack of data on outcomes in patients with MF treated with ruxolitinib and anemia medications. During the European Hematology Association (EHA) 2025 Congress, June 12–15, 2025, Milan, IT, Pankit Vachhani presented the findings from a post hoc analysis of the phase III JUMP trial (NCT01493414). This analysis evaluated the treatment patterns and clinical outcomes in patients with MF treated with ruxolitinib and ESAs or danazol. 

The post hoc analysis from the JUMP trial (N = 2233) included 101 patients with MF with a baseline hemoglobin (Hb) level of <12.0 g/dL, including a subset of 52 patients with an Hb level of <10.0 g/dL. Eligible patients received ESAs (epoetin, n = 81; darbepoetin, n = 17) or danazol (n = 3) within 3 months of enrollment and remained on therapy for ≥3 months. The clinical outcomes assessed included spleen length and symptom response.

Key learnings

Spleen length response rates were comparable between the two groups and the overall JUMP patient population. At 12 and 24 weeks, the ≥50% spleen length reduction rates were 41.6% vs 42.3% vs 39.1% and 36.6% vs 34.6% vs 31.5% in the Hb <12.0 g/dL, Hb <10.0 g/dL, and overall JUMP groups. 

Symptoms responses at 24 weeks were also comparable; the ≥6.5 point increase in FACT-Lym TS was observed in 25.7%, 23.1%, and 26.9% of patients in the Hb <12.0 g/dL, Hb <10.0 g/dL, and overall JUMP groups.

The mean percentage change in Hb level from baseline to Week 48 was +1.5% and +6.5% in the Hb <12.0 g/dL and the Hb <10.0 g/dL groups, respectively. Additionally, 3 patients in the Hb <10.0 g/dL group were TI at 24 weeks.

Ruxolitinib at a >25 mg daily dose was well tolerated. The findings suggest that ESAs or danazol as a potential option for managing anemia in combination with ruxolitinib, allowing maintenance of ruxolitinib dose intensity in patients with MF and anemia.