...the combination of MEK and CDK4/6 inhibitors ( trametinib (3 mg/kg QOD) and palbociclib (100 mg/kg QD)) yielded significantly greater tumor growth inhibition in the PDX model compared to vehicle-treated controls or treatment with monotherapy of each drug alone (see Figure 5D). Notably, this PDX model responded to the combination despite harboring an atypical KRAS A146T mutation and an activating AKT1 E17K mutation. The combination treatment yielded regression of tumors after 21 days, unlike treatment with either monotherapy...