Table 4.
Comparison of HER2 Ratio and Average HER2 Gene Copy Number and ASCO-CAP Groupings With Clinical Outcomes in BCIRG-006
| HER2 FISH (HER2/CEP17) Ratio | HER2 Copies per Cell | No. of Subjects | DFS Control, Events/No. of Subjects | DFS Trastzumab, No. of Events/Subjects | DFS, HR (95% CI)* | DFS P for Log-Rank Test* | OS Control | OS Trastzumab | OS, HR (95% CI)* | OS P for Log-Rank Test* | ASCO-CAP FISH Group |
|---|---|---|---|---|---|---|---|---|---|---|---|
| ≥ 2.0 | < 4.0 | 46 | 4/18 | 6/28 | 1.10 (0.31 to 3.89) | .8860 | 2/18 | 4/28 | 3.15 (0.35 to 28.63) | .2839 | Group 2 |
| ≥ 4 | 3,109 | 251/1,031 | 391/2,078 | 0.71 (0.60 to 0.83) | < .0001 | 138/1,031 | 202/2,078 | 0.69 (0.55 to 0.85) | .0006 | Group 1 | |
| Total | 3,155 |
NOTE. The HRs are for trastuzumab treatment arms compared with control chemotherapy-only arm. There were too few patients (n = 5) accrued to BCRIG-006 with a HER2 FISH ratio < 2.0 and ≥ 6.0 average HER2 gene copy number/tumor cell for analysis of the HR.
Abbreviations: BCIRG, Breast Cancer International Research Group; CAP, College of American Pathologists; DFS, disease-free survival; HER2, human epidermal growth factor receptor 2; HR, hazard ratio; OS, overall survival.
*
Trastuzumab-containing treatment arms compared with control (chemotherapy alone) treatment arm.