DESTINY-Breast06 Trial

ENHERTU was investigated in DESTINY-Breast06

A Phase 3, international, randomized, open-label trial designed to evaluate ENHERTU vs chemotherapy in eligible patients with HR+/HER2-low and HER2-ultralow mBC1-4

The study design for the DESTINY-Breast06 trial, a randomized 1:1 trial of patients with confirmed HR+/HER2-low metastatic breast cancer (IHC 1+ or IHC 2+/ISH–) or HER2-ultralow (IHC 0 with membrane staining) (N=866) The study design for the DESTINY-Breast06 trial, a randomized 1:1 trial of patients with confirmed HR+/HER2-low metastatic breast cancer (IHC 1+ or IHC 2+/ISH–) or HER2-ultralow (IHC 0 with membrane staining) (N=866)”

Primary endpoint1

  • PFS (assessed by BICR) in the HER2-low population

Key secondary endpoints1

  • PFS (assessed by BICR) in the overall study population (HER2-low and HER2-ultralow)
  • OS in the HER2-low and overall study population (HER2-low and HER2-ultralow)

Select secondary endpoints3

  • Confirmed ORR and DOR in the HER2-low population
  • Confirmed ORR and DOR in the overall study population (HER2-low and HER2-ultralow)

Select exploratory endpoints2,3

  • PFS, ORR, and DOR in the HER2-ultralow population

Stratification factors1

  • HER2 IHC status (IHC 1+ or IHC 2+/ISH– or IHC 0 with membrane staining)
  • Prior CDK4/6 inhibitor
  • Prior taxane in the non-metastatic setting

aDisease progression on at least 2 previous lines of ET with or without a targeted therapy (eg, CDK4/6, mTOR, or PI3K inhibitors) administered for the treatment of metastatic disease.

bOnly 1 line of ET in the metastatic setting required.

cIHC 1+ tumors and IHC 0 tumors were ISH– or ISH untested.

dPatients could have received chemotherapy in the neoadjuvant or adjuvant setting as long as they have had a disease-free interval of >12 months.

eTreatment continued until disease progression or unacceptable toxicity.

fIn the control arm, 60% of patients received capecitabine, 24% nab-paclitaxel, and 16% paclitaxel.

Select baseline patient demographics and clinical characteristics2,4

DESTINY-Breast06
(N=866)
Age, median 57 (range: 28-87)
HER2 IHC scoreg IHC 1+ 55%
ISH 2+/ISH– 27%
IHC 0 with membrane
staining
18%
Prior CDK4/6 inhibitor in the metastatic setting 89%
Number of prior lines
of ET in the metastatic
setting
1 147/863; 17%
2 583/863; 68%
≥3 133/863; 15%
Time to progression
on prior ET + CDK4/6
inhibitor
≤6 months 77/863; 9%
>6 months 786/863; 91%
Prior chemotherapy in non-metastatic setting 53%
Visceral disease 85%
Sites of metastases Liver 67%
Lung 32%
Brain or CNS
metastases
8%
Bone-only disease 3%
DESTINY-Breast06
(N=866)
Age, median 57 (range: 28-87)
HER2 IHC scoreg
IHC 1+ 55%
ISH 2+/ISH– 27%
IHC 0 with
membrane staining
18%
Prior CDK4/6 inhibitor in the metastatic setting 89%
Number of prior lines of ET in the metastatic setting
1 147/863; 17%
2 583/863; 68%
≥3 133/863; 15%
Time to progression on prior ET + CDK4/6 inhibitor
≤6 months 77/863; 9%
>6 months 786/863; 91%
Prior chemotherapy in non-metastatic setting 53%
Visceral disease 85%
Sites of metastases
Liver 67%
Lung 32%
Brain or CNS
metastases
8%
Bone-only disease 3%
  • Gender: 99.9% were female, 0.1% were male1
  • Race/ethnicity: 53% were White, 35% were Asian, 7% were Hispanic/Latino, 0.8% were Black or African American, and 0.1% were American Indian or Alaska Native1
  • ECOG PS: 59% had ECOG PS 0 and 39% had ECOG PS 1 at baseline1,h

In DESTINY-Breast06, ~85% of patients had received 1-2 lines of ET in the metastatic setting1

gIHC 1+ tumors and IHC 2+ tumors were ISH–.

h14 patients in the overall study population (5 patients in the ENHERTU group and 9 patients in the chemotherapy group) had missing ECOG PS scores at baseline but had a score of 0 or 1 recorded within 6 days after randomization.

1L, first line; BICR, blinded independent central review; CDK4/6, cyclin-dependent kinases 4 and 6; CNS, central nervous system; DOR, duration of response; ECOG, Eastern Cooperative Oncology Group; ET, endocrine therapy; HER2, human epidermal growth factor receptor 2; HR+, hormone receptor-positive; IHC, immunohistochemistry; ISH, in situ hybridization; IV, intravenous; mBC, metastatic breast cancer; mTOR, mammalian target of rapamycin; ORR, objective response rate; OS, overall survival; PFS, progression-free survival; PI3K, phosphatidylinositol 3-kinase; PS, performance score; Q3W, every 3 weeks.