Table 1.
Patients and disease baseline characteristics, overall and according to primary resistance vs. sensitivity to dual HER2 blockade.
| Characteristics | Overall study population (N = 68) N (%) | Resistant patients (n = 33) n (%) | Sensitive patients (n = 35) n (%) | P |
|---|---|---|---|---|
| Age (years) | — | — | — | >0.999 |
| <70 | 55 (81) | 27 (82) | 28 (80) | — |
| ≥70 | 13 (19) | 6 (18) | 7 (20) | — |
| Sex | — | — | — | 0.811 |
| Female | 38 (56) | 19 (58) | 19 (54) | — |
| Male | 30 (44) | 14 (42) | 16 (46) | — |
| ECOG PS | — | — | — | <0.001 |
| 0 | 41 (60) | 12 (36) | 29 (83) | — |
| 1–2 | 27 (40) | 21 (64) | 6 (17) | — |
| Primary tumor location | — | — | — | 0.349 |
| Right colon | 4 (6) | 3 (9) | 1 (3) | — |
| Left colon/Rectum | 64 (94) | 30 (91) | 34 (97) | — |
| Primary tumor resection | — | — | — | >0.999 |
| Yes | 14 (21) | 26 (79) | 28 (80) | — |
| No | 54 (79) | 7 (21) | 7 (20) | — |
| Prior adjuvant chemotherapy | — | — | — | 0.806 |
| Yes | 26 (38) | 21 (64) | 21 (60) | — |
| No | 42 (62) | 12 (36) | 14 (40) | — |
| Metastatic sites (N) | — | — | — | 0.580 |
| 1 | 17 (25) | 7 (21) | 10 (29) | — |
| >1 | 51 (75) | 26 (79) | 25 (71) | — |
| Prior exposure to anti-EGFR | — | — | — | 0.786 |
| Yes | 18 (27) | 8 (24) | 10 (29) | — |
| No | 50 (73) | 25 (76) | 25 (71) | — |
| Prior treatment lines (N) | — | — | — | 0.341 |
| 1–2 | 31 (46) | 13 (39) | 18 (51) | — |
| ≥3 | 37 (54) | 20 (61) | 17 (49) | — |
| Anti-HER2 therapy | — | — | — | 0.079 |
| mAbs | 44 (65) | 25 (76) | 19 (54) | — |
| TKI plus trastuzumab | 24 (35) | 8 (24) | 16 (46) | — |
Abbreviations: ECOG PS, Eastern Cooperative Oncology Group performance status; mAb, monoclonal antibody; TKI, tyrosine-kinase inhibitor.