Table 3.
Efficacy outcomes according to RAS status and predictive model in validation cohort.
| RAS assessable (n=141) |
RAS wild-type (n=123) |
RAS wild-type/ Model-defined responsive group (n=83) |
RAS wild-type/ Model-defined refractory group (n=40) |
|||||
|---|---|---|---|---|---|---|---|---|
| Cetuximab plus chemotherapy (n=67) |
Chemotherapy alone (n=74) |
Cetuximab plus chemotherapy (n=58) |
Chemotherapy alone (n=65) |
Cetuximab plus chemotherapy (n=42) |
Chemotherapy alone (n=41) |
Cetuximab plus chemotherapy (n=16) |
Chemotherapy alone (n=24) |
|
| Overall response | ||||||||
| CR | 1 (1.5%) | 1 (1.4%) | 1 (1.7%) | 1 (1.5%) | 1 (2.4%) | 1 (2.4%) | 0 (0%) | 0 (0%) |
| PR | 39 (58.2%) | 21 (28.4%) | 37 (63.8%) | 18 (27.7%) | 33 (78.6%) | 11 (26.8%) | 4 (25.0%) | 7 (29.2%) |
| SD | 16 (23.9%) | 26 (35.1%) | 12 (20.7%) | 23 (35.4%) | 6 (14.2%) | 14 (34.1%) | 6 (37.5%) | 9 (37.5%) |
| PD | 10 (14.9%) | 25 (33.8%) | 7 (12.1%) | 22 (33.8%) | 2 (4.8%) | 14 (34.1%) | 5 (31.3%) | 8 (33.3%) |
| Not assessable∗ | 1 (1.5%) | 1 (1.4%) | 1 (1.7%) | 1 (1.5%) | 1 (2.4%) | 1 (2.2%) | 0 (0%) | 0 (0%) |
|
| ||||||||
| ORR, % | 59.7 | 29.7 | 65.5 | 29.2 | 81.0 | 29.3 | 25.0 | 29.2 |
| OR | 3.50 | 4.60 | 7.45 | 0.59 | ||||
| 95% CI | 1.74-7.04 | 2.15-9.84 | 2.88-19.27 | 0.05-5.61 | ||||
| P (Chi-square or Fisher's) | <0.001 | <0.001 | <0.001 | 1.000 | ||||
| p for interaction test | 0.005 | |||||||
|
| ||||||||
| Radical resection rate of LM, % | 28.4 | 10.8 | 32.8 | 10.8 | 40.5 | 9.8 | 12.5 | 12.5 |
| OR | 3.27 | 4.04 | 6.29 | 1.00 | ||||
| 95% CI | 1.32-8.08 | 1.55-10.51 | 1.89-20.92 | 0.15-6.77 | ||||
| p(Chi-square or Fisher's) | 0.008 | 0.003 | 0.001 | 1.000 | ||||
|
| ||||||||
| PFS, months | ||||||||
| Median | 10.0 | 5.8 | 10.5 | 5.6 | 11.3 | 4.7 | 8.6 | 7.4 |
| 95%CI | 7.5-10.5 | 3.7-6.3 | 8.2-11.8 | 3.7-6.3 | 9.0-13.0 | 2.1-5.9 | 6.7-9.3 | 4.6-7.5 |
| HR | 0.63 | 0.54 | 0.45 | 0.83 | ||||
| 95%CI | 0.44-0.91 | 0.37-0.80 | 0.28-0.74 | 0.44-1.59 | ||||
| p(log-rank) | 0.004 | <0.001 | 0.001 | 0.534 | ||||
| p for interaction test | 0.094 | |||||||
|
| ||||||||
| OS, months | ||||||||
| Median | 31.7 | 23.7 | 36.8 | 21.6 | 42.0 | 20.3 | 24.8 | 23.0 |
| 95%CI | 21.2-44.8 | 15.7-28.3 | 23.4-48.6 | 15.6-28.4 | NE-NE | 11.4-28.6 | 20.6-27.4 | 14.3-29.7 |
| HR | 0.54 | 0.45 | 0.27 | 0.92 | ||||
| 95%CI | 0.33-0.89 | 0.26-0.77 | 0.13-0.58 | 0.41-2.06 | ||||
| p(log-rank) | 0.011 | 0.003 | <0.001 | 0.828 | ||||
| p for interaction test | 0.020 | |||||||
∗ 1 early death (less than 3 months) and 1 lost to follow-up before the first time evaluation by MDT.
CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease; ORR, objective response rate; LM, liver metastases; PFS, progression free survival; OS, overall survival; HR, hazard ratio; OR, odds ratio; 95% CI, 95% confidence interval. MDT, multidisciplinary team; NE, not evaluable.