Oral PIM1 Kinase Inhibitor Receives FDA Fast Track Designation for Myelofibrosis

The FDA has granted Fast Track Designation to the investigational oral PIM1 kinase-selective inhibitor nuvisertib for the treatment of immediate or high-risk myelofibrosis. This new designation for the drug was announced in a press release by its developer, Sumitomo Pharma America, Inc. (SMPA).

“Receiving FDA Fast Track Designation for nuvisertib in the treatment of myelofibrosis reinforces our confidence in its potential as a treatment option for patients facing a poor prognosis with limited treatment options,” commented SMPA president and chief executive officer Tsutomu Nakagawa, PhD. SMPA is the operations arm in the United States for Japan-based global pharmaceutical company Sumitomo Pharma Co., Ltd.

Nuvisertib previously received Orphan Drug Designation from the FDA for myelofibrosis in May 2022 and from the Japan Ministry of Health, Labour and Welfare in November 2024.

An ongoing phase 1/2 study of nuvisertib in patients with relapsed or refractory myelofibrosis is currently underway, and a preliminary data update from the study was given at the European Hematology Association (EHA) 2025 Congress in Milan, Italy.

Regarding the safety of this agent shown in the data presented at the Congress, nuvisertib monotherapy was well tolerated in patients with myelofibrosis and involved no dose-limiting toxicities. Among efficacy-evaluable patients, 22.2% had spleen volume reduction of 25% or greater with the drug, and 44.4% had a reduction in total symptom score of 50% or greater. Improvements in bone marrow fibrosis, platelet count, and hemoglobin levels were observed in 42.9%, 26.7%, and 24% of patients, respectively. A significant statistical correlation was also calculated between the cytokine modulation produced by nuvisertib and clinical responses in patients’ symptoms and spleen (P<0.001).

“The data observed to date demonstrate promising clinical activity for nuvisertib and the strong potential for selective PIM1 inhibition to slow the progression of myelofibrosis,” remarked SMPA chief medical officer – oncology Jatin Shah, MD.