Information LY 3200882 is a potent, highly selective inhibitor ofTGF-β receptor type 1 (TGFβRI). It potently inhibits TGFβ mediated SMAD phosphorylation in vitro in tumor and immune cells and in vivo in subcutaneous tumors in a dose dependent fashion. Targets TGFβRI In vitro LY3200882 inhibits various pro-tumorigenic activities. LY3200882 potently inhibits TGFβ mediated SMAD phosphorylation in vitro in tumor and immune cells and in vivo in subcutaneous tumors in a dose dependent fashion. In in vitro immune suppression assays, LY3200882 has shown the ability to rescue TGFβ1 suppressed or T regulatory cell suppressed naïve T cell activity and restore proliferation. It acts as an immune modulatory agent. In vivo In preclinical tumor models, LY3200882 showed potent anti-tumor activity in the orthotopic 4T1-LP model of triple negative breast cancer and this activity correlated with enhanced tumor infiltrating lymphocytes in the tumor microenvironment. Durable tumor regressions in the orthotopic 4T1-LP model were observed and rechallenge of congenic tumors resulted in complete rejection in all mice. LY3200882 has shown anti-metastatic activity in an experimental metastasis tumor model (intravenous EMT6-LM2 model of triple negative breast cancer). In addition, LY3200882 shows combinatorial anti-tumor benefits with checkpoint inhibition (anti-PD-L1) in the syngeneic CT26 model.