Based on the results of the PK study, the efficacy of 50 mg/kg of the PI3K inhibitor WX-037 and 2 mg/kg of the MEK inhibitor WX-554 given orally, as single agents and in combination, was assessed in HCT116 human tumour xenograft-bearing mice (Fig. 5). The gene discussed is PIK3CA; the disease is neoplasm.