Temuterkib (LY3214996) is a potent and selective, orally available inhibitor of the extracellular signal-regulated kinase (ERK) 1 and 2, with potential antineoplastic activity.

ERK2:5 nM, ERK1:5 nM

Temuterkib is a highly selective inhibitor of ERK1 and ERK2, with IC50 of 5 nM for both enzymes in biochemical assays. Temuterkib potently inhibits cellular phospho-RSK1 in BRAF and RAS mutant cancer cell lines. In an unbiased tumor cell panel sensitivity profiling for inhibition of cell proliferation, tumor cells with MAPK pathway alterations including BRAF, NRAS or KRAS mutation are generally sensitivity to Temuterkib[1].

In tumor xenograft models, LY3214996 effectively inhibits the PD biomarker phospho-p90RSK1 and its PD effects, correlating with compound exposure and antitumor activity. It demonstrates comparable or superior efficacy to existing ERK inhibitors in BRAF or RAS mutant cell lines and xenografts. Oral administration of LY3214996 notably suppresses tumor growth across various cancer xenografts, including BRAF or NRAS mutant melanoma, and BRAF or KRAS mutant colorectal, lung, and pancreatic cancers, showing good tolerance. It offers a promising therapeutic strategy for cancers linked to MAPK pathway alterations. Remarkably, LY3214996 also counters Vemurafenib-resistant A375 melanoma xenografts, highlighting its potential in treating melanoma patients unresponsive to BRAF therapy. Furthermore, LY3214996 can be used alongside investigational and approved treatments, especially in KRAS mutant cases. Its combination with the CDK4/6 inhibitor abemaciclib exhibits significant tumor growth inhibition or regression in diverse cancer models, including KRAS mutant colorectal and non-small cell lung cancers, showcasing its broad therapeutic potential[1].