Trametinib DMSO solvate displays remarkable potency in cellular assays for ERK1/2 phosphorylation and growth inhibition and excellent in vivo activity.?Inhibition of the MEK?ERK pathway offers a very promising therapeutic strategy for cancers with activating mutant Ras and Raf, and GSK1120212 (DMSO solvate) has been advanced into phase III trials for advanced or metastatic BRAF mutant melanoma as well as phase I and II studies in subjects with solid tumors or leukemia.

Trametinib DMSO solvate was then evaluated in vivo in an A549 (KRAS mutant cell line) xenograft model, orally dosing daily for 21 days (qd × 21).Near complete tumor growth inhibition was observed at 5.0 and 2.5 mg/kg [92 and 87% tumor growth inhibition (TGI), respectively] and to a lesser degree at 0.5 and 0.1 mg/kg (62 and 58% TGI).?[Notably, although 5 mg/kg was the maximally tolerated dose (MTD) , 3 mg/kg is the typically observed MTD.] Dose-dependent antitumor activity with GSK1120212 (DMSO solvate) treatment has been similarly reported for several other KRAS and BRAF mutant tumor models.