Dr. Pemmaraju on the Ongoing Trial of Tagraxofusp in Myelofibrosis

Naveen Pemmaraju, MD, associate professor, Department of Leukemia, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, discusses the ongoing phase I/II trial of tagraxofusp (SL-401; Elzonris) in patients with intermediate- or high-risk relapsed/refractory myelofibrosis.

Tagraxofusp is a first-in-class anti—CD123 targeted agent. Approximately 20 years ago, CD123 was found to be overexpressed in leukemia cells. Pemmaraju was part of the effort that led to the FDA approval of the agent in blastic plasmacytoid dendritic cell neoplasm (BPDCN). Since then, CD123 has been found to be overexpressed in several other blastoid and myeloid malignancies.

With this background, researchers sought to evaluate the agent’s efficacy in a phase I/II trial in an area of high unmet need: myelofibrosis and chronic myelomonocytic leukemia. In the phase II part of the trial, 23 patients have been treated to date. Patients have a median age of 65 years and have received at least 1 prior line of therapy, reflective of a real-world population. Approximately half of patients have experienced spleen reductions, which is considered to be a surrogate marker for meaningful clinical response. The agent is known to cause fluid retention and capillary leak syndrome, which has been reported in 1 patient. Apart from this, the safety profile of the agent was consistent with prior findings. The phase II portion is currently ongoing, and will continue to accrue patients.