Table 4.
Exposure to study drugs and time and duration of dose modifications in Japanese postmenopausal patients with ER+/HER2− ABC receiving palbociclib plus letrozole
| Overall exposure | Palbociclib + Letrozole N = 42 |
|---|---|
| Duration of treatment in days, na | |
| 1‐28 | 0 |
| 29‐90 | 1 |
| 91‐180 | 6 |
| 181‐364 | 6 |
| ≥365 | 29 |
| Median duration (range), d | 438.0 (56‐585) |
| Median number of cycles (range), n | 14 (2‐21) |
| Drug‐specific dose modifications and exposures |
Palbociclib N = 42 |
Letrozole N = 42 |
|---|---|---|
| Dose reductions | ||
| ≥1 dose reduction, n (%)b , c | 25 (59.5) | — |
| Patients with a dose reduction to 100 mg | 17 (40.5) | — |
| Patients with a dose reduction to 75 mg | 8 (19.0) | — |
| Median time to dose reduction (range), dd | — | |
| First dose reduction | 64 (29‐232) | |
| Second dose reduction | 114 (64‐415) | |
| Dose interruption, n (%)e | 35 (83.3) | 30 (71.4) |
| Median average duration of dose interruption (range), df | 5.5 (1.0‐8.5) | 1.0 (1.0‐24.5) |
| Median time to first dose interruption (range), dd | 15 (5‐124) | 107 (5‐404) |
| Cycle delay, n (%) | 39 (92.9) | 8 (19.0) |
| Median average duration of cycle delay, d (range) | 7 (5‐47) | 7 (5‐47) |
| Median relative dose intensity per week (range), %g | 74.2 (38.0‐99.8) | 99.7 (69.6‐100) |
ABC, advanced breast cancer; d, day; ER+, estrogen receptor‐positive; HER2, human epidermal growth factor receptor 2‐negative.
Total number of dosing days (from the first day until and including the last day) of each study treatment.
Any dose reduction from the initial prescribed dose, regardless of duration (does not include dose interruptions).
Total number of patients categorized at the maximum dose reduction.
Time to first event (dose reduction/dose interruption) = (start date of first occurrence minus first dose date of cycle 1) + 1; for dose interruption, time could not be calculated for some patients as a result of unknown dates for missing doses.
0 mg given on a planned dosing day. Could not be calculated for some patients as a result of unknown dates for missing doses.
During total cycles.
Overall relative dose intensity = (sum of overall cycles of actual total dose per cycle/sum over all cycles of the actual number of weeks in cycle)/(sum over all cycles of intended total dose per cycle/sum over all cycles of intended number of weeks per cycle) × 100. —, not applicable because a dose reduction for letrozole was not allowed per the study protocol.