Tizaterkib (AZD0364) is a potent and selective ERK2 inhibitor extracted from patent WO2017080979A1, compound example 18, has an IC50 of 0.6 nM.IC50 & Target: IC50: 0.6 nM (ERK2)In Vitro: Tizaterkib is measured in the ERK2 mass spectrometry and A375 phospho-p90RSK assays with IC50s of 0.6 nM and 5.7 nM, respectively. Tizaterkib can inhibit the growth of a panel of cancer cell lines (A549, H2122, H2009, and Calu6 cell lines) with KRAS mutations as a monotherapy and this effect is synergistically enhanced by treatment with Selumetinib.In Vivo: Tumor growth inhibition by Tizaterkib ethanesulfonic acid (Example 18a) in combination with MEK inhibitor Selumetinib is measured. Studies are performed in the A549 xenograft model. Selumetinib is dosed twice daily (BiD) 8 hours apart and Tizaterkib ethanesulfonic acid is dosed once daily (QD) 4 hours after the first Selumetinib dose. Both compounds are dosed continuously for 3 weeks. Both vehicles are dosed in the vehicle group. Both Selumetinib and Tizaterkib ethanesulfonic acid reduce tumor growth relative to vehicle only control. The combination of Selumetinib and Tizaterkib ethanesulfonic acid results in a reduction in tumor growth.