Table 2

Response of CPT-11 refractory xenografts to IMC-C225 and CPT-11

Fractional tumor volume (FTV)a relative to control animals
Combination therapy
DaybSwitch to IMC-C225Continued CPT-11ExpectedcObservedRatio of expected: observed FTVd
DLD-1360.5660.5440.3080.2691.144
400.4950.4950.2450.2131.149
430.4560.4750.2170.1711.268
470.4040.4740.1910.1431.335
500.3930.4670.1840.1231.498
HT-29360.4200.4850.2040.1901.073
400.3550.4390.1560.1401.115
430.3450.4670.1610.1201.343
470.2950.4230.1250.0961.307
500.2870.4050.1160.0741.562
  • a FTV, calculated as mean tumor volume experimental/mean tumor volume control.

  • b Day after start of treatment. Tumor volumes were measured twice weekly (n = 8 for each group of mice).

  • c (Mean FTV of IMC-C225) × (mean FTV of CPT-11).

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