Table 5.
Subgroup analyses of patients with visceral metastases and after previous endocrine therapy: intention-to-treat population
|
Visceral metastases (n = 90) |
Endocrine resistance (Cohort C, n = 67) |
||||
|---|---|---|---|---|---|
|
Cohort A* (n = 23) |
Cohort B* (n = 17) |
Cohort C* (n = 50) |
Primary endocrine resistance (n = 19) |
Secondary endocrine resistance(n = 48) | |
| Best of response, n (%) | |||||
| CR | 1 (4.3) | 0 | 0 | 2 (10.5) | 0 |
| PR | 11 (47.8) | 9 (52.9) | 20 (40.0) | 9 (47.4) | 20 (41.7) |
| SD | 10 (43.5) | 7 (41.2) | 24 (48.0) | 5 (26.3) | 24 (50.0) |
| PD | 0 | 1 (5.9) | 6 (12.0) | 3 (15.8) | 4 (8.3) |
| Not evaluable | 1 (4.3) | 0 | 0 | 0 | 0 |
| ORR (%, 95% CI) | 52.2 (30.59–73.18) | 52.9 (27.81–77.02) | 40.0 (26.41–54.82) | 57.9 (33.50–79.75) | 41.7 (27.61–56.79) |
| DCR (%, 95% CI) | 95.7 (78.05–99.89) | 94.1 (71.31–99.85) | 88.0 (75.69–95.47) | 84.2 (60.42–96.62) | 91.7 (80.02–97.68) |
| CBR (%, 95% CI) | 69.6 (47.08–86.79) | 82.4 (56.57–96.20) | 64.0 (49.19–77.08) | 57.9 (33.50–79.75) | 77.1 (62.69–87.97) |
| Survival estimates | |||||
| Median PFS (months, 95% CI) | NR (9.20–NR) | 26.3 (7.43–NR) | 12.7 (7.03–27.14) | 8.9 (3.65–24.02) | 25.7 (11.93–NR) |
*Cohort A: bireociclib plus letrozole/anastrozole group; Cohort B: bireociclib plus FULV first-line; Cohort C: bireociclib plus FULV second-line. Cohorts A & B for treatment naïve patients in the metastatic setting; Cohort C for patients who progressed on or after prior endocrine therapy. CBR clinical benefit rate; CI confidence interval; CR, complete response; DCR, disease control rate; FULV fulvestrant; NR not reached; ORR, objective response rate; PD, progressive disease; PFS progression-free survival; PR, partial response; SD, stable disease.