Trametinib-13C-d3 is intended for use as an internal standard for the quantification of trametinib (Item No. 16292) by GC- or LC-MS. Trametinib is an inhibitor of MEK1 and -2.1 It inhibits B-RAF- and C-RAF-induced phosphorylation of MEK1 (IC50s = 3.4 and 1.8 nM, respectively) and MEK2 (IC50s = 1.6 and 0.92 nM, respectively). Trametinib inhibits the growth of two human colorectal cancer cell lines expressing mutant B-RAF (IC50s = 0.48 and 0.52 nM) and seven cell lines expressing mutant K-Ras (IC50s = 2.2-174 nM) but does not inhibit the growth of wild-type COLO 320DM cells expressing both B-RAF and K-Ras (IC50 = >10,000 nM). It reduces tumor growth in HT-29 and COLO 205 mouse xenograft models when used at doses of 0.3 and 1 mg/kg per day. Trametinib (0.03 and 0.1 mg/kg per day) also decreases M. tuberculosis-induced increases in hind paw volume in a rat model of arthritis.2 Formulations containing trametinib, in combination with dabrafenib, have been used in the treatment of B-RAFV600E mutant metastatic melanoma.WARNING This product is not for human or veterinary use.