DESTINY-Breast03 Phase 3 Study Results
DESTINY-Breast04: First Randomized Phase 3
Study of T-DXd for HER2-low mBC
An open-label, multicenter study (NCT03734029)
DESTINY-Breast04
Patientsa
HER2-low (IHC 1+ vs IHC
2+/ISH-), unresectable, and/or
mBC treated with 1-2 prior
R
lines of chemotherapy in the
2:1
metastatic setting
HR+ disease considered
10
Daiichi-Sankyo
T-DXd
5.4 mg/kg Q3W
(n = 373)
HR+ = 480
HR-= 60
TPC
Capecitabine, eribulin,
gemcitabine, paclitaxel,
nab-paclitaxelc
(n = 184)
Primary endpoint
• PFS by BICR (HR+)
Key secondary endpointsb
PFS by BICR (all patients)
•
OS (HR+ and all patients)
endocrine refractory
Stratification factors
•
Centrally assessed HER2 statusd (IHC 1+ vs IHC 2+/ISH-)
1 versus 2 prior lines of chemotherapy
HR+ (with vs without prior treatment with CDK4/6 inhibitor) versus HR-
ASCO/CAP, American Society of Clinical Oncology/College of American Pathologists; BICR, blinded independent central review; CDK, cyclin-dependent kinase; DOR, duration of response; HER2, human epidermal growth factor receptor 2;
HR, hormone receptor; IHC, immunohistochemistry; ISH, in situ hybridization; mBC, metastatic breast cancer; OS, overall survival; PFS, progression-free survival; Q3W, every 3 weeks; R, randomization; T-DXd, trastuzumab deruxtecan;
TPC, treatment of physician's choice.
"If patients had HR+ mBC, prior endocrine therapy was required. Other secondary endpoints included ORR (BICR and investigator), DOR (BICR), PFS (investigator), and safety; efficacy in the HR- cohort was an exploratory endpoint. "TPC was
administered accordingly to the label. "Performed on adequate archived or recent tumor biopsy per ASCO/CAP guidelines using the VENTANA HER2/neu (4B5) investigational use only [IUO] Assay system.
ASCO 2022 #LBA3 Plenary Session
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