Table 3

Study design II. Fractional tumor volume (FTV) relative to untreated controls for gefitinib, cetuximab and combination treatment (expected vs. observed)

Day*Gefitinib (50 mg/kg)Cetuximab (1.5 mg/mouse)ExpectedObservedR
70.7120.3350.2390.0673.6
140.8090.3950.3200.01817.8
210.8780.3570.3130.00652.2
  • Note. FTV = (mean tumor volume experimental)/(mean tumor volume control).

  • * Day after start of treatment.

  • (Mean FTV of gefitinib) × (mean FTV of cetuximab).

  • Obtained by dividing the expected FTV by the observed FTV. A ratio of >1 indicates a synergistic effect, and a ratio of <1 indicates a less than additive effect.