Table 2

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

Day*Gefitinib (25 mg/kg)Cetuximab (1 mg/mouse)ExpectedObservedR
70.5550.5590.3100.1402.2
140.6470.6100.3950.1003.9
210.7980.7500.5990.0777.8
  • 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.