Despite the decreased PDE3A enzymatic inhibition profile of BAY 2666605, the occurrence of thrombocytopenia in treated patients, an on-target effect of the compound, precluded the achievement of a therapeutic window, consequently leading to trial termination.
More analogs were prepared and tested with the goal of increasing metabolic stability and decreasing PDE3 inhibition while maintaining the cellular activity of BRD9500. This led to the discovery of BAY 2666605, a compound optimized for clinical testing.
We also determined that the velcrins BAY 2666605 and BRD3800 induce tumor regression in subcutaneous glioblastoma PDX models. Velcrins have antitumor activity in preclinical models of glioblastoma, warranting further investigation as potential therapeutic agents.
P1, N=5, Terminated, Bayer | Completed --> Terminated; Due to the high probability of not achieving a therapeutic window and lack of evidence of sufficient clinical benefit.