Table 2. Univariate analyses of biomarker and treatment outcomes.
| Criteria (No. of patients) | Responders (%) | P-value | Median TTP (mo) | P-value | Median OS (mo) | P-value | |
|---|---|---|---|---|---|---|---|
| Tumour expression (IHC) | |||||||
| TSa | <25 (13) | 9 (69.2) | 0.21 | 4.8 | 0.78 | N/R | 0.15 |
| >25 (25) | 12 (48) | 5.5 | 8.2 | ||||
| TPa | <25 (20) | 13 (65) | 0.20 | 7.2 | 0.10 | N/R | 0.021 |
| >25 (18) | 8 (44.4) | 3.8 | 7.0 | ||||
| ERCC1a | <130 (16) | 11 (68.8) | 0.15 | 7.2 | 0.60 | N/R | 0.022 |
| >130 (22) | 10 (45.5) | 5.0 | 7.0 | ||||
| EGFRb | (−) (12) | 5 (41.7) | 0.25 | 2.8 | 0.18 | 6.1 | 0.33 |
| 1+ in ⩾10% (26) | 16 (61.5) | 5.9 | N/R | ||||
| HER2b | 0/1+ (32) | 16 (50) | 0.20 | 5.3 | 0.20 | 9.9 | 0.47 |
| 2+/3+ (6) | 5 (83.3) | 7.2 | N/R | ||||
| Gene copy number (FISH) | |||||||
| HER2/CEP17 | <2.0 (33) | 18 (54.5) | 1.0 | 5.3 | 0.18 | 9.9 | 0.66 |
| >2.0 (5) | 3 (60) | N/R | N/R | ||||
| Serum protein level (ELISA) | |||||||
| EGFR (ng ml−1) | <41.9 (13) | 6 (46.2) | 0.42 | 5.5 | 0.73 | 5.6 | 0.12 |
| >41.9 (25) | 15 (60) | 5.5 | N/R | ||||
| EGF (pg ml−1) | <667 (20) | 15 (75) | 0.01 | 7.6 | 0.88 | N/R | 0.51 |
| >667 (18) | 6 (33.3) | 5.0 | 7.6 | ||||
| TGF-α (pg ml−1) | <14 (21) | 15 (71.4) | 0.03 | 5.9 | 0.47 | N/R | 0.31 |
| >14 (17) | 6 (35.3) | 4.8 | 7.6 | ||||
| Amphiregulin (pg ml−1) | <1.14 (16) | 7 (43.8) | 0.22 | 5.0 | 0.89 | 6.1 | 0.34 |
| >1.14 (22) | 14 (63.6) | 7.2 | N/R | ||||
CEP, chromosome enumerator probe; EGF, epidermal growth factor; EGFR, epidermal growth factor receptor; ELISA, enzyme-linked immunosorbent assay; ERCC1, excision repair cross-complementation group 1; FISH, fluorescence in situ hybridization; HER2, human epidermal growth factor receptor 2; IHC, immunohistochemistry; mo, months; N/R, not reached; OS, overall survival; TGF, transforming growth factor; TP, thymidine phosphorylase; TS, thymidylate synthase; TTP, time-to-progression.
Numbers in the criteria denote IHC scores derived from staining intensity and percentage of positive cells.
IHC score cutoff for EGFR was 7.5 which was identical to 1+ staining in 10% or more cancer cells. The cutoff for HER2 was 15, which was identical to 2+ staining in at least 10% of cells.