DESTINY-Breast03 Phase 3 Study Results
Baseline Demographics and Clinical Characteristics in BC Cohorts
Baseline Characteristics
Median ageb, years (range)
Female, n (%)
Region, n (%)
Cohort 1
HER2+
n = 32a
55.5
(36.3-76.2)
Cohort 2
HER2-low
n = 16
47.3
(34.4-64.7)
Overall
N = 48
Treatment History
Cohort 1
HER2+
n = 32a
Cohort 2
HER2-low
n = 16
Overall
N = 48
53.6
(34.4-76.2)
32 (100)
16 (100)
48 (100)
Number of lines of unique regimens
for metastatic/locally advanced
unresectable setting, n (%)
0
Europe
12 (37.5)
9 (56.3)
21 (43.8)
1
1 (3.1)
0
2 (12.5)
1 (6.3)
3 (6.3)
1 (2.1)
United States
20 (62.5)
7 (43.8)
27 (56.3)
2
3 (9.4)
1 (6.3)
4 (8.3)
3
5 (15.6)
1 (6.3)
6 (12.5)
ECOG PSC, n (%)
0
20 (62.5)
8 (50.0)
28 (58.3)
≥4
23 (71.9)
11 (68.8)
34 (70.8)
1
12 (37.5)
8 (50.0)
20 (41.7)
Lines of unique regimens for
HER2 expressiond, n (%)
IHC 1+
0
6 (37.5)
6 (12.5)
metastatic/locally advanced
unresectable setting,
5 (0-14.0)
4 (0-10.0)
4.5 (0-14.0)
IHC 2+
5 (15.6)
10 (62.5)
15 (31.3)
median (range)
ISH+
5 (100)
0
5 (33.3)
History of brain metastasis, n (%)
7 (21.9)
3 (18.8)
10 (20.8)
ISH equivocal
0
1 (10.0)
1 (6.7)
ISH-
0
9 (90.0)
9 (60.0)
IHC 3+
27 (84.4)
0
27 (56.3)
HR status, n (%)
Positive
Negative
20 (62.5)
13 (81.3)
12 (37.5)
3 (18.8)
33 (68.8)
15 (31.3)
ESMO BC 2022 #1620 Oral
ECOG PS, Eastern Cooperative Oncology Group performance status; HER2, human epidermal growth factor receptor 2; HR, hormone receptor; IHC, immunohistochemistry; ISH, in situ hybridization; RDE, recommended
dose for expansion.
aIncludes 3 patients treated at T-DXd 5.4 mg/kg RDE in combination with nivolumab 360 mg during part 1. Median age at informed consent. Performance status on the ECOG scale ranges from 0 to 5, with higher scores
indicating greater disability. HER2 expression was centrally confirmed prospectively by analysis of archival tissue (most recent tumor tissue preferred) according to the guidelines from the American Society of Clinical
Oncology/College of American Pathologists. According to these guidelines, HER2 positivity was defined as HER2 IHC 3+ or IHC 2+/ISH+.
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