PLK1 and neoplasm: Consistent with in vitro target residency and occupancy data (Figures 1A–C) analysis for tumor TTK and PLK1 target occupancy showed that TTK was fully occupied by BAL0891 for ≥96 hours after the last dose, whereas PLK1 was only partially occupied (46%) at 24 hours and almost completely unoccupied after 48 and 96 hours (Figure 3E).