BAY 1125976 inhibits activation of AKT in cell lines carrying the AKT-activating mutation E17K. In KU-19-19 bladder cancer cells activation by phosphorylation is inhibited at AKT1-S473 and 4EBPI-T70 with IC50 values of 35 and 100 nM, respectively. In the prostate cancer cell line LAPC-4, the phosphorylation of AKT1-S473, T308 and 4EBP1-T70 is inhibited with IC50 values of 0.8, 5.6 and 35 nM, respectively. Treatment of LAPC-4 cells with BAY 1125976 results in an inhibition of PRAS40 phosphorylation at T246 as a direct target of AKT1 activity with an IC50 of ∼141 nM. BAY 1125976 inhibits the proliferation of the breast cancer cell lines BT-474, T47D, MCF7, ZR-75–1, EVSA-T, MDA-MB-453, KPL-4 and BT20 as well as the prostate cancer cell lines LNCaP and LAPC-4 with submicromolar IC50 values. Breast cancer cell lines of luminal type show strong inhibition of cell proliferation following BAY 1125976 treatment.^[1].

Treatment with different doses of BAY 1125976 results in potent antitumor efficacy in KPL-4 tumor bearing mice. A clear, statistically significant dose-response is observed after daily oral treatment with 25 or 50 mg/kg BAY 1125976 with T/C_volume ratios of 0.14 and 0.08, respectively. Daily administration of 25 or 50 mg/kg BAY 1125976 results in significant antitumor efficacy in MCF7-implanted nude mice compared with the control with T/C_volume values of 0.25 and 0.25 and T/C_weight values of 0.33 and 0.37, respectively. BAY 1125976 displays good antitumor efficacy in vivo in AKT1^E17K mutated models.^[1].