Table 1

Effect of C225 on radioresponse of A431 tumor xenografts in nude mice

TreatmentaTime in days that tumors required to grow from 8 to 12 mmAbsolute growth delaybNormalized growth delaycEnhancement factorsd
No treatment6.5 ± 0.4e
C225 (single)12.0 ± 2.85.5 ± 2.8
C225 (multiple)13.9 ± 3.57.4 ± 3.5
18 Gy25.8 ± 3.419.3 ± 3.4
C225 single plus 18 Gy42.7 ± 3.336.2 ± 3.330.7 ± 3.31.59
C225 multiple plus 18 Gy83.8 ± 10.177.3 ± 10.169.9 ± 10.13.62
  • a Mice bearing 8-mm tumors in the right hind leg were given i.p. 1 mg of C225 antibody once or three times, local tumor irradiation, or the antibody plus local tumor irradiation. Three injections of C225 were given 3 days apart. When the two agents were combined, C225 was given 6 h before or 6 h before and 3 and 6 days after local tumor irradiation. Groups consisted of 6–8 mice each.

  • b Absolute tumor growth delay caused by radiation, C225, or both agents is defined as the time in days tumors required to reach 12 mm from the time of treatment initiation minus the time in days untreated tumors required to grow from 8 to 12 mm.

  • c Normalized tumor growth delay is defined as the time in days for tumors to reach 12 mm in the mice treated with the combination of C225 and radiation minus the time in days to reach 12 mm in mice treated with C225 only.

  • d Enhancement factors were obtained by dividing normalized tumor growth delay in mice treated by C225 plus radiation with the absolute growth delay in mice treated with radiation only.

  • e Mean ± SE.