Patient demographics and baseline characteristics
| Parameter | Dose escalation n = 15 (%) | Dose expansion n = 18 (%) | Overall n = 33 (%) | ||
|---|---|---|---|---|---|
| Median age (range) | 65 (45–78) | 66 (43–75) | 65 (43–78) | ||
| ECOG performance status | |||||
| 0 | 7 (47%) | 14 (78%) | 21 (64%) | ||
| 1 | 8 (53%) | 4 (22%) | 12 (36%) | ||
| Menopausal status, n (%) | |||||
| Premenopausal or perimenopausal | 2 (13%) | 1 (6%) | 3 (9%) | ||
| Postmenopausal | 13 (87%) | 17 (94%) | 30 (91%) | ||
| Histology | |||||
| Invasive ductal carcinoma/no special type | 10 (67%) | 15 (83%) | 25 (76%) | ||
| Invasive lobular carcinoma | 4 (27%) | 1 (6%) | 5 (15%) | ||
| Others or not specified | 1 (7%) | 2 (11%) | 3 (9%) | ||
| Receptor statusa | |||||
| ER | |||||
| Strong | 12 (80%) | 17 (94%) | 29 (88%) | ||
| Moderate | 3 (20%) | 1 (6%) | 4 (12%) | ||
| Weak | 0 (0%) | 0 (0%) | 0 (0%) | ||
| PgR | |||||
| Strong | 11 (73%) | 8 (44%) | 19 (58%) | ||
| Moderate | 1 (7%) | 3 (17%) | 4 (12%) | ||
| Weak | 2 (13%) | 3 (17%) | 5 (15%) | ||
| Negative | 1 (7%) | 4 (22%) | 5 (15%) | ||
| BCL2 | |||||
| Strong | 11 (73%) | 17 (94%) | 28 (85%) | ||
| Moderate | 4 (27%) | 1 (6%) | 5 (15%) | ||
| Weak | 0 (0%) | 0 (0%) | 0 (0%) | ||
| Median Ki67 % (range) | 10% (1–30) | 30% (5–60) | 15% (1–60) | ||
| Sites of disease | |||||
| Bone | 14 (93%) | 12 (67%) | 26 (79%) | ||
| Visceral metastases | 9 (60%) | 11 (61%) | 20 (61%) | ||
| Liver | 3 (20%) | 8 (44%) | 11 (33%) | ||
| Lung | 7 (47%) | 5 (28%) | 12 (36%) | ||
| Nodal | 7 (47%) | 9 (50%) | 16 (48%) | ||
| Adjuvant endocrine therapy (%) | |||||
| Tamoxifen only | 6 (40%) | 5 (28%) | 11 (33%) | ||
| Aromatase inhibitor only | 2 (13%) | 4 (22%) | 6 (18%) | ||
| Tamoxifen and aromatase inhibitor | 1 (7%) | 5 (28%) | 6 (18%) | ||
| Other (toremefine) | 1 (7%) | 0 (0%) | 1 (3%) | ||
| None | 5 (33%) | 4 (22%) | 9 (27%) | ||
| Prior lines of metastatic therapy, n (%) | |||||
| 0 | 3 (20%) | 8 (44%) | 11 (33%) | ||
| 1 | 3 (20%) | 4 (22%) | 7 (21%) | ||
| ≥2 | 9 (60%) | 6 (33%) | 15 (45%) | ||
| Mean prior lines of treatment (range) | 2.7 (0–6) | 1.5 (0–8) | 2.0 (0–8) | ||
| Prior tamoxifen exposure (%) | |||||
| None | 5 (33%) | 7 (39%) | 12 (36%) | ||
| Adjuvant setting only | 4 (27%) | 9 (50%) | 13 (39%) | ||
| Metastatic setting only | 3 (20%) | 1 (6%) | 4 (12%) | ||
| Adjuvant and metastatic | 3 (20%) | 1 (6%) | 4 (12%) | ||
| Prior disease progression on tamoxifen | |||||
| Yes | 6 (40%) | 3 (17%) | 9 (27%) | ||
| No | 9 (60%) | 15 (83%) | 24 (73%) | ||
| Prior chemotherapy exposure (%) | |||||
| None | 5 (33%) | 7 (39%) | 12 (36%) | ||
| Adjuvant setting only | 4 (27%) | 5 (28%) | 9 (27%) | ||
| Metastatic setting only | 3 (20%) | 2 (11%) | 5 (15%) | ||
| Adjuvant and metastatic | 3 (20%) | 4 (22%) | 7 (21%) | ||
↵Abbreviation: ECOG, Eastern Cooperative Oncology Group.aSixteen patients were enrolled based on results of archival tissue.