ERK pathway inhibitors: how low should we go?

Resistance to RAF inhibitors is generally accompanied by reactivation of extracellular signal-regulated kinase (ERK) signaling. SCH772984, a selective, ATP-competitive inhibitor of ERK1 and ERK2, is effective in BRAF-mutant models in which resistance is the result of ERK reactivation. SCH772984 may also have a role in the treatment of tumors in which ERK is dysregulated by mutant RAS, NF1, or activated receptor tyrosine kinases, settings in which current RAF inhibitors are ineffective.