Table 1:
Baseline Patient Characteristics:
| Patient Characteristics | ||||||
|---|---|---|---|---|---|---|
|
| ||||||
| Cohort 1 (n 34) | Cohort 2 (n 48) | Cohort 3 (n 127) | ||||
|
| ||||||
| First CDK4/6i exposure | CDK4/6i re-treatment | First CDK4/6i exposure | CDK4/6i re-treatment | First CDK4/6i exposure | CDK4/6i re-treatment | |
|
| ||||||
| Prognostic Markers | ||||||
|
| ||||||
| Median Age | 61 | 62 | 56 | 58 | 61 | 63 |
|
| ||||||
| Bone Only Metastases* | 9 (26%) | 9 (26%) | 18 (37.5%) | 15 (31.2%) | 40 (31.2%) | 23 (18%) |
|
| ||||||
| Sites of metastatic disease | ||||||
| 1 | 18 (53%) | 18 (53%) | 22 (46%) | 17 (35%) | 49 (39.6%) | 25 (19.7%) |
| 2 | 6 (18%) | 4 (12%) | 11 (23%) | 9 (19%) | 35 (27.6%) | 31 (24.4%) |
| 3 | 6 (18%) | 8 (24%) | 10 (21%) | 12 (25%) | 20 (15.8%) | 29 (22.9%) |
| =4 | 4 (12%) | 4 (12%) | 5 (10%) | 10 (21%) | 23 (18.1%) | 42 (33.1%) |
|
| ||||||
| Brain Metastasis | 1 (3%) | 1 (3%) | 3 (6%) | 5 (10%) | 10 (7.9%) | 14 (11%) |
|
| ||||||
| Endocrine Partner | ||||||
|
| ||||||
| Aromatase Inhibitor | 22 (65%) | 16 (47%) | 44 (92%) | 1 (2%) | 68 (54%) | 14 (11%) |
|
| ||||||
| SERD | 11 (32%) | 15 (44%) | 1 (2%) | 45 (94%) | 51 (40%) | 78 (61%) |
|
| ||||||
| Tamoxifen | 0 | 0 | 0 | 1 (2%) | 0 | 1 (0.7%) |
|
| ||||||
| No Endocrine partner | 1 (3%) | 3 (9%) | 3 (6%) | 1 (2%) μ | 8 (6%) ß | 34 (27%) |
|
| ||||||
| CDK4/6i | ||||||
|
| ||||||
| Palbociclib | 28 (82%) | 15 (44%) | 45 (94%) | 45 (94%) | 122 (96.1%) | 4 (3.2%) |
|
| ||||||
| Abemaciclib | 4 (12%) | 16 (47%) | 3 (6%) | 3 (6%) | 4 (3.2%) | 104 (81.9%) |
|
| ||||||
| Ribociclib | 2 (6%) | 3 (9%) | 0 | 0 | 1 (0.8%) | 19 (15%) |
|
| ||||||
| Treatment Sequencing | ||||||
|
| ||||||
| CDK4/6i retrial immediately after initial CDK4/6i failure | 31 (91%) | 41 (85.4%) | 45 (35.4%) | |||
|
| ||||||
| Median Lines of Therapy for Metastatic Disease | 1 | 3 | 1 | 2 | 2 | 5 |
|
| ||||||
| First line | 19 (56%) | 0 | 29 (60%) | 0 | 43 (33.9%) | 0 |
|
| ||||||
| Second line | 6 (18%) | 16 (47%) | 7 (15%) | 28 (58%) | 28 (22.1%) | 17 (13.4%) |
|
| ||||||
| Third line | 1 (3%) | 7 (21%) | 4 (8%) | 6 (13%) | 18 (14.2%) | 23 (18.1%) |
|
| ||||||
| Fourth and beyond | 8 (24%) | 11 (32%) | 8 (17%) | 14 (29%) | 38 (30%) | 87 (68.5%) |
*
Patient with bone lesions and breast primary lesion and/or lymph node involvement were included as bone only as far as no presence of visceral disease.
μ
One patient received bicalutamide as endocrine partner
?
Six patients received bicalutamide as endocrine partner