BAL0891

BAL0891 is a novel, first-in-class small molecule drug that acts as a dual inhibitor of threonine tyrosine kinase (TTK; also known as monopolar spindle 1 kinase or Mps1) and polo-like kinase 1 (PLK1). These kinases are critical regulators of the mitotic spindle assembly checkpoint (SAC), which ensures accurate chromosome segregation during cell division. By simultaneously inhibiting both TTK and PLK1, BAL0891 disrupts the SAC, forcing tumor cells through mitosis prematurely and leading to aberrant cell division and apoptosis. This mechanism results in potent anti-cancer activity across various solid tumor models. The drug is being developed primarily for advanced solid tumors—including triple negative breast cancer—and has shown single-agent efficacy in preclinical studies. BAL0891 was originally developed by Crossfire Oncology BV, later in-licensed by NTRC in 2018, and its rights were subsequently acquired by Basilea Pharmaceutica. Clinical development is ongoing with Phase 1/2 trials targeting relapsed/refractory solid tumors and specific cancers such as stomach cancer and acute myeloid leukemia[2][3][6][8].