Table 1

Data summary of the in vivo generation of A431 recurrent variants displaying a resistant phenotype to a second cycle of treatment with anti-EGFR Abs

GroupmAb (dosing)aMice per groupRecurrent tumors (%)Tumor I.D.bInitial size first cyclecInitial size second cycleSecond cycled (no. of injections × dose)Recurrent variant obtainedObservations
ImR3 (0.25 mg)54 (80)T21445505 × 0.25 mgnoMice 2 and 5 euthanized
T31132258 × 0.25 mgR1, R2
T41072398 × 0.25 mg + 8 × 1 mgnoCells from T4 did not plate.
T52085877 × 0.25 mgno
IImR3 (1 mg)54 (80)T12706001 × 1 mgnoMouse 1 euthanized (open tumor)
T33525757 × 1 mgR6
T43044517 × 1 mgnoCells from T4 did not plate.
T52983688 × 1 mgnoMouse 5 was found dead after eighth injection of second cycle.
IIIhR3 (0.25 mg)52 (40)T22703208 × 0.25 mg + 8 × 1 mgR3
T5352446same as T2R4
IVhR3 (1 mg)41 (25)T32253618 × 1 mgR5
VC225 (0.25 mg)51 (20)T12214962 × 0.25 mgnoMouse was euthanized
VIC225 (1 mg)41 (25)T22883048 × 1 mg-break- 8 × 1 mgnoTumor did not regress or grow back after second cycle. It began to regrow during a third cycle. Cells could not be recovered.
  • a This dose of the given Ab was injected every other day for 2 weeks during the first cycle of treatment.

  • b Tumor I.D., the number assigned to a particular tumor in a group of treatment.

  • c Initial size, the size of the tumor (in mm3) at time 0 in either first or second cycle of treatment.

  • d Injections in second cycle of treatment were given every other day.