In vivo regimens to test PKI-587 efficacy in the HCT116 [K-Ras, PIK3CA (H1047R)] model were guided by in vitro data. In vitro, PKI-587 inhibited HCT116 growth (IC50 = 8 nmol/L) and suppressed p-Akt (T308) at 30 nmol/L or more after 18 hours of exposure ...Combined, irinotecan (40 mg/kg) and PKI-587 (12.5 mg/kg), day 1, 5, 9 regimen, prevented HCT116 tumor size increase in a 13-day study ...