Table 1.
Patient, Tumor, and Treatment Characteristics
| Characteristic | All (N = 86) | Cohort 1 (n = 41) | Cohort 2 (n = 45) |
|---|---|---|---|
| No. (%) | No. (%) | No. (%) | |
| Median age, years (range) | 52 (32-83) | 55 (32-77) | 50 (33-83) |
| Sex | |||
| Female | 86 (100) | 41 (100) | 45 (100) |
| Male | 0 (0) | 0 (0) | 0 (0) |
| Race | |||
| White | 79 (92) | 36 (88) | 43 (96) |
| Black or African American | 4 (5) | 2 (5) | 2 (4) |
| Asian | 1 (1) | 1 (2) | 0 (0) |
| Other | 2 (2) | 2 (5) | 0 (0) |
| Ethnicity | |||
| Hispanic or Latino | 4 (5) | 3 (7) | 1 (2) |
| Non-Hispanic | 78 (91) | 35 (85) | 43 (96) |
| Unknown | 4 (5) | 3 (7) | 1 (2) |
| ECOG PS at baseline | |||
| 0 | 56 (65) | 26 (63) | 30 (67) |
| 1 | 28 (33) | 14 (34) | 14 (31) |
| 2 | 2 (2) | 1 (2) | 1 (2) |
| Stage at initial diagnosis | |||
| I | 9 (10) | 4 (10) | 5 (11) |
| II | 22 (26) | 11 (27) | 11 (24) |
| III | 28 (33) | 10 (24) | 18 (40) |
| IV | 25 (29) | 16 (39) | 9 (20) |
| Unknown | 2 (2) | 0 (0) | 2 (4) |
| Hormone receptor status | |||
| Primary tumor | |||
| ER positive and/or PgR positive | 52 (60) | 27 (66) | 25 (56) |
| ER negative and PgR negative | 32 (37) | 13 (32) | 19 (42) |
| Unknown/not done | 2 (2) | 1 (2) | 1 (2) |
| Metastatic lesion | |||
| ER positive and/or PgR positive | 41 (48) | 16 (39) | 25 (56) |
| ER negative and PgR negative | 33 (38) | 17 (41) | 16 (36) |
| Unknown/not done | 12 (14) | 8 (20) | 4 (9) |
| HER2 status | |||
| Primary tumor | |||
| Positive | 70 (81) | 33 (80) | 37 (82) |
| Negative/equivocal | 10 (12) | 5 (12) | 5 (11) |
| Unknown/not done | 6 (7) | 3 (7) | 3 (7) |
| Metastatic lesion | |||
| Positive | 73 (85) | 33 (80) | 40 (89) |
| Negative/equivocal | 1 (1) | 0 (0) | 1 (2) |
| Unknown/not done | 12 (14) | 8 (20) | 4 (9) |
| Disease-free interval, years | |||
| 0 (de novo metastatic breast cancer) | 25 (29) | 16 (39) | 9 (20) |
| < 2 | 22 (26) | 8 (20) | 14 (31) |
| ≥ 2 | 39 (45) | 17 (41) | 22 (49) |
| Median No. of metastatic disease sites (range)* | 3 (1-6) | 3 (1-6) | 2 (1-5) |
| Disease site | |||
| CNS | 6 (7) | 1 (2) | 5 (11) |
| Lung | 32 (37) | 20 (49) | 12 (27) |
| Pleural effusion | 7 (8) | 3 (7) | 4 (9) |
| Liver | 38 (44) | 20 (49) | 18 (40) |
| Bone | 39 (45) | 19 (46) | 20 (44) |
| Breast or chest wall | 46 (53) | 22 (54) | 24 (53) |
| Lymph nodes | 59 (69) | 32 (78) | 27 (60) |
| Other | 11 (13) | 6 (15) | 5 (11) |
| Adjuvant or neoadjuvant hormonal therapy | 32 (37) | 11 (27) | 21 (47) |
| Adjuvant or neoadjuvant chemotherapy | 46 (53) | 19 (46) | 27 (60) |
| Anthracycline | 42 (49) | 17 (41) | 25 (56) |
| Taxane | 38 (44) | 14 (34) | 24 (53) |
| Trastuzumab | 29 (34) | 8 (20) | 21 (47) |
| No. of lines of chemotherapy for metastasis or recurrence* | |||
| None | 46 (53) | 39 (95) | 7 (16) |
| 1 | 21 (24) | 1 (2) | 20 (44) |
| 2 | 15 (17) | 0 (0) | 15 (33) |
| ≥ 3 | 4 (5) | 1 (2) | 3 (7) |
| Prior chemotherapy for metastasis or recurrence | |||
| Trastuzumab | 39 (45) | 1 (2) | 38 (84) |
| Trastuzumab-emtansine | 1 (1) | 1 (2) | 0 (0) |
| Pertuzumab | 0 (0) | 0 (0) | 0 (0) |
Abbreviations: ECOG PS, Eastern Cooperative Oncology Group performance status; ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; PgR, progesterone receptor.
*
Retrospective review of patient records later determined that some patients had received more than the allowed number of prior regimens. All analyses were based on initial cohort assignment per treating investigator.