Table 2.
Trastuzumab, HER2-targeted therapy, chemotherapy, and endocrine therapy treatments and durations
| Older patients (> 65) | Younger patients (< 65) | All Patients | |
|---|---|---|---|
| Patients, n | 1583 | 3821 | 5404 |
| Trastuzumab | |||
| Number of trastuzumab courses,a n patients | |||
| One course | 1583 (100%) | 3821 (100%) | 5404 (100%) |
| Two courses | 319 (20%) | 1079 (28%) | 1398 (26%) |
| Three or more courses | 61 (4%) | 341 (9%) | 402 (7%) |
| Median time on all trastuzumab treatment,b months (IQR) | 14.1 (5.9–32.1) | 18.2 (8.7–40.9) | 16.8 (7.8–38.2) |
| Median duration of the first uninterrupted course of trastuzumab, months (IQR) | 12.1 (4.6–24.9) | 14.0 (6.5–28.9) | 13.5 (5.9–27.6) |
| Trastuzumab monotherapy only, n | 154 (10%) | 163 (4%) | 317 (6%) |
| HER2-targeted therapies | |||
| Treated with other HER2-targeted therapies for MBC, n: | 340 (21%) | 1404 (37%) | 1744 (32%) |
| Lapatinib | 182 (11%) | 950 (25%) | 1132 (21%) |
| Pertuzumab | 91 (6%) | 284 (7%) | 375 (7%) |
| T-DM1 | 101 (6%) | 300 (8%) | 401 (7%) |
| Median time on all HER2-targeted therapies,b months (IQR) | 15.4 (6.3–37.0) | 21.5 (10.1–48.8) | 19.4 (8.8–45.0) |
| Median proportions of observed survival timec on all HER2-targeted therapies, including trastuzumab, % (IQR) | 85% (58–100%) | 85% (61–99%) | 85% (60–99%) |
| Chemotherapy | |||
| Dispensed chemotherapy, n | 1170 (74%) | 3342 (87%) | 4512 (83%) |
| Median number of unique chemotherapies dispensed per person, n (IQR) | 1 (0–2) | 2 (1–3) | 2 (1–3) |
| Median time on all chemotherapy,b months (IQR) | 5.6 (3.3–10.8) | 8.3 (4.5–16.5) | 7.4 (4.2–15.1) |
| Median proportion of survival time on chemotherapy, % (IQR) | 30% (13–53%) | 38% (18–62%) | 36% (16–60%) |
| Endocrine therapy | |||
| Dispensed endocrine therapy, nd | 885 (56%) | 2179 (57%) | 3064 (57%) |
| Median time on all endocrine therapy,b,d months (IQR) | 14.5 (3.8–41.2) | 16.4 (4.9–43.6) | 15.8 (4.6–42.6) |
| Median proportion of survival time on endocrine therapy, % (IQR) | 60% (27–88%) | 49% (20–80%) | 52% (21–82%) |
aA course is defined as consecutive dispensings of trastuzumab closer in time than 90 days. A gap of ≥ 90 days between trastuzumab dispensings was considered a break in trastuzumab therapy and the subsequent dispensing considered the start of a new course of therapy.
bExcluding breaks in treatment ≥ 90 days
cObserved duration of treatment, excluding breaks, as a proportion of observed survival time from initiation of trastuzumab for MBC
dOnly endocrine therapies dispensed between 30 days prior to initiating trastuzumab for MBC and death or censor