Transforming growth factor (TGF)-β signaling facilitates tumor growth and metastasis in advanced cancer. Use of inhibitors of TGF-β signaling may thus be a novel strategy for the treatment of patients with such cancer. A-77-01 is a close analogue of A-83-01 and has a very similar biological profile of A-83-01. A-83-01 is found to decompose to A-77-01 under certain circumstances and A-77-01 is likely an active component or metabolite of its prodrug A-83-01.In vitro: A-77-01 and A-83–01 almost completely inhibited the transcriptional activation induced by the constitutively active TGF-β type I receptor (ALK5-TD). A-77-01 and A-83-01 were five to 10 times more potent than the ALK-5 inhibitor SB-431542. In contrast, treatment with 1 μM A-77-01 or 1 μM A-83-01 had no effects on BMP-induced transcriptional activity. However, A-83-01, but not A-77–01, weakly suppressed the transcriptional activity induced by BMP4 at concentrations above 3 μM. A-83-01 and A-77-01 had weak effects on osmotic shock-induced p38 MAPK activity only at high concentrations. A-83-01 and A-77-01 restored the expression of E-cadherin and repressed that of fibronectin and N-cadherin more efficiently than SB-431542 [1]. In vivo: No animal in-vivo data available currently. Clinical trial: A-77-01 is currently in the preclinical developlent stage and no clinical data are available.Reference:[1] Tojo M, Hamashima Y, Hanyu A, Kajimoto T, Saitoh M, Miyazono K, Node M, Imamura T. The ALK-5 inhibitor A-83-01 inhibits Smad signaling and epithelial-to-mesenchymal transition by transforming growth factor-beta. Cancer Sci. 2005;96(11):791-800.