PDE5A and colonic neoplasm: The improved PDE5 and 10 inhibitory activity of ADT-094 was paralleled with increased potency to inhibit the growth of human HCT116 and HT29 colon tumor cell lines with IC50 values of 0.1 μmol/L, while SS inhibited growth with IC50 values of 51 and 68 μmol/L, respectively (Figure 3C).