Table 1.
Baseline demographics, prior cancer therapies, and biomarker status.
| Venetoclax plus fulvestrant | Fulvestrant | |
|---|---|---|
| n = 51 | n = 52 | |
| Median age, years | 58.0 | 59.5 |
| <65 | 38 (74.5) | 34 (65.4) |
| ECOG performance status | ||
| 0 | 28 (54.9) | 31 (59.6) |
| Race,an (%) | ||
| White | 40 (78.4) | 46 (88.5) |
| Asian | 6 (11.8) | 3 (5.8) |
| Black or African American | 3 (5.9) | 2 (3.8) |
| Breast cancer histologic subtypeb | ||
| Ductal | 40 (78.4) | 34 (65.4) |
| Lobular | 10 (19.6) | 16 (30.8) |
| Other | 5 (9.8) | 8 (15.4) |
| Site of metastatic disease (≥1 lesion) | ||
| Visceralc | 47 (92.2) | 43 (82.7) |
| Liver | 35 (68.6) | 28 (53.8) |
| Lung | 19 (37.3) | 18 (34.6) |
| Boned | 36 (70.6) | 39 (75.0) |
| Line of prior metastatic breast cancer ET | ||
| 1 | 41 (80.4) | 43 (82.7) |
| 2 | 10 (19.6) | 9 (17.3) |
| Prior cancer therapy | ||
| Neoadjuvant | 12 (23.5) | 7 (13.5) |
| Adjuvant | 30 (58.8) | 27 (51.9) |
| Metastatic (ET) | 51 (100) | 52 (100) |
| CDK4/6 inhibitor (metastatic) | ||
| Palbociclib | 29 (56.9) | 39 (75.0) |
| Ribociclib | 22 (43.1) | 13 (25.0) |
| Median duration of therapy, months (range) | 15.0 (1.8–51.2) | 16.5 (1.9–63.0) |
| BCL2 statuse | ||
| High | 33 (64.7) | 34 (65.4) |
| Low | 18 (35.3) | 18 (34.6) |
| Gene mutationsf | n = 48 | n = 46 |
| PIK3CA SV | 19 (39.6) | 14 (30.4) |
| ESR1 SV | 21 (43.8) | 19 (41.3) |
| TP53 SV | 23 (47.9) | 16 (34.8) |
| RB1 SV | 9 (18.8) | 4 (8.7) |
| CDH1 SV | 9 (18.8) | 5 (10.8) |
| PTEN SV | 5 (10.4) | 4 (8.7) |
| BRCA2 SV | 4 (8.3) | 2 (4.3) |
| ERBB2 SV | 4 (8.3) | 1 (2.2) |
| AKT1 SV | 2 (4.2) | 4 (8.7) |
| ATM SV | 2 (4.2) | 3 (6.5) |
| FGFR1 CNA | 4 (8.3) | 7 (15.2) |
Note: Data are n (%) unless otherwise specified.
Abbreviations: BCL2, B-cell lymphoma 2; CDK4/6, cyclin-dependent kinase 4/6; CNA, copy-number alteration; ECOG, Eastern Cooperative Oncology Group; ET, endocrine therapy; SV, short variant.
aVenetoclax plus fulvestrant arm: one patient - multiple categories, one patient - unknown (2.0%); fulvestrant arm: one patient - unknown (1.9%).
bMissing at time of snapshot: venetoclax plus fulvestrant: one patient (1.9%); fulvestrant: four patients (7.7%).
cVisceral: lung, liver, adrenal gland, central nervous system, pleural cavity, or peritoneal cavity.
dThere were two patients with bone-only metastatic lesions, one in each arm.
eBCL2 clinical status was determined as “high” if ≥50% of tumor cells expressed BCL2 at 2+ or 3+ staining intensity by immunohistochemistry. Note: 62% of tissue specimens were archival, collected >1 year prior to study start; 39% of tissue specimens were from metastatic sites compared with 59% from primary sites (unknown in two patients). There were no patients who had tumor specimens collected from both primary and metastatic sites.
fGene mutation analysis is based only on known or likely pathogenic SVs and CNAs detected with a prevalence of >5% in the total population of samples evaluable for plasma circulating tumor DNA.