DESTINY-Breast03 Phase 3 Study Results
Study Design
Daiichi-Sankyo
Patritumab Deruxtecan: U31402-A-J101
KEY ELIGIBILITY CRITERIA
Advanced/unresectable or
metastatic breast cancer
HER3-positivea
DE/DF & HR+/HER2- DEXP
•≥2 and ≤6 lines of prior
chemotherapy; ≥2 for
advanced disease
Dose expansion: TNBC
.
• 1 to 2 prior chemotherapy
regimens for advanced
disease
Dose Escalation (DE)b
Any BC Subtype
Dose Finding (DF)
Any BC Subtype
8.0 mg/kg IV Q3W n=6
6.4 mg/kg IV Q3W n=15
4.8 mg/kg IV Q3W n=15
3.2 mg/kg IV Q3W
n=3
4.2 mg/kg IV Q2W x 3 cycles
then 6.4 mg/kg IV Q3W (n=12) |
1.6 mg/kg IV Q3W
n=3
Data for all 3 phases were pooled
•
•
3.2 4.8 6.4 mg/kg Q3W
then 6.4 mg/kg Q3W (n=12)
Dose Expansion (DEXP)
HER3-High
HR+/HER2-
6.4 mg/kg IV Q3W
(n=31)
4.8 mg/kg IV Q3W
(n=33)
TNBC
6.4 mg/kg IV Q3W
(n=31)
HER3-Lowc
HR+/HER2-
6.4 mg/kg IV Q3W
(n=21)
Efficacy is reported by BC subtype: HR+/HER2- (n=113) TNBC (n=53), and HER2+ (n=14)
Safety is reported for patients who received HER3-DXd 4.8 mg/kg (n=48), 6.4 mg/kg (n=98), and
all patients (N=182d)
DE, dose escalation; DEXP, dose expansion; DF, dose finding; EWOC, escalation with overdose control; HR, hormone receptor; IHC, immunohistochemistry; mCRM, modified continuous reassessment method;
Q2W, once every 2 weeks; Q3W, once every 3 weeks; R, randomized; TNBC, triple-negative breast cancer.
a HER3 status was determined by IHC; HER3-positive was defined as IHC 2+ and IHC 3+ for DE/DF cohorts and as ≥25% membrane positivity at 10x for DEXP cohorts. b Guided by mCRM with EWOC. CHER3-
high was defined as >75% membrane positivity at 10x; HER3-low was defined as ≥25% and ≤75% membrane positivity at 10x. d Includes two patients with unknown BC subtype.
ASCO 2022 #1002 Oral
55
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