DDR1 and neoplasm: The average IC50 for DDR1-IN-1 is 2.549 μmol/L, which was comparable to 7rh (3.627 μmol/L) (Fig. 5A and 5B), but the colony formation assay revealed that the sustained anti-tumor activity of DDR1-IN-1 monotherapy was substantially attenuated compared with 7rh over time, suggesting a divergence in durability of effects despite comparable initial efficacy (Fig. 5C).