DESTINY-Breast03 Phase 3 Study Results
Exposure-Adjusted Incidence Rates (EAIRS) a
Daiichi-Sankyo
DESTINY-Breast03
Patients remaining on treatment, n (%)
116 (45.1)
39 (14.9)
Treatment duration, median (range), months
16.1
(0.7-33.0)
6.9
(0.7-28.5)
Exposure, patient-yearsb
327.2
186.3
EAIR, grade ≥3 TEAE
0.42
0.70
EAIR, any grade serious TEAE
0.17
0.27
EAIR, grade ≥3 serious TEAE
0.12
0.20
Exposure-adjusted incidence per
total patient-years of exposure
T-DXd
n = 257
T-DM1
n = 261
EAIRS were measured to account for
differences in treatment duration
exposure between T-DXd and T-DM1
and provide a more meaningful
comparison
EAIRS per patient-year were lower in
the T-DXd arm than the T-DM1 arm
except for TEAEs associated with
drug discontinuation, which were
primarily associated with
ILD/pneumonitis in the T-DXd arm
EAIR for grade ≥3 TEAES was
0.42 for T-DXd and 0.70 for
T-DM1
•
EAIR, TEAE associated with drug
0.12
0.10
discontinuation
•
EAIR, TEAE associated with dose reduction
0.18
0.19
EAIR for any grade serious TEAES
was 0.17 for T-DXd and 0.27 for
T-DM1
EAIRS, exposure-adjusted incidence rates; T-DM1, trastuzumab emtansine; T-DXd, trastuzumab deruxtecan; TEAE, treatment-emergent adverse event.
aEAIR was the number of patients with at least 1 event incidence divided by the sum of patient-years of exposure over patients in the safety analysis set (total patient-years of exposure). "Patient years of exposure were the treatment duration with year as unit.
Safety update: Sept 7, 2021
ASCO 2022 #1000 Oral
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