A phase 1/2 study evaluated tagraxofusp (Elzonris), a CD123-targeted therapy, as a single-agent treatment for patients with myelofibrosis. The drug showed modest clinical benefit but was generally well tolerated, with no dose-limiting toxicities reported. These findings suggest tagraxofusp may be better suited for use in combination with other therapies rather than as a standalone treatment.
The trial included patients who had previously failed JAK inhibitor therapy and those who were treatment-naive. Most patients achieved stable disease, and about 40% experienced symptom improvement in both groups. Median overall survival ranged from 19.3 months in relapsed or refractory patients to 26.6 months in treatment-naive patients, while progression-free survival varied between the groups.
Tagraxofusp had a predictable safety profile, with no treatment-related deaths. Capillary leak syndrome occurred in 11% of patients but resolved quickly, and common side effects included mouth sores, nausea, weight gain, fever, and chills. About one-fifth of patients discontinued treatment due to side effects. By targeting CD123, which is overexpressed in myelofibrosis, tagraxofusp may help disrupt the disease environment, supporting ongoing studies of combination treatment strategies.