Table 1.

Patient Demographics and Clinical Characteristics

Characteristic	T-DXd 5.4 mg/kg N = 184^a

Median age (range), years	55.0 (28–96)

Age group, n (%)
<65 years	140 (76.1)
≥65 years	44 (23.9)

Female, n (%)	184 (100.0)

Region, n (%)
Asia	63 (34.2)
North America	53 (28.8)
Europe	68 (37.0)

ECOG PS, n (%)
0	102 (55.4)
1	81 (44.0)
2	1 (0.5)

Hormone receptor, n (%)
Positive	97 (52.7)
Negative	83 (45.1)
Unknown	4 (2.2)

HER2 expression,^b n (%)
IHC 3+	154 (83.7)
IHC 2+/IHC 1+, ISH+	28 (15.2)
Not evaluable	2 (1.1)

History of visceral disease at baseline, n (%)	169 (91.8)

History of brain metastases,^c n (%)	24 (13.0)
Presence of brain metastases at baseline,^c n (%)	7 (3.8)

Sum of diameters of target lesions, median (range), cm²	5.8 (1.2–24.5)

Median number of prior treatments for metastatic disease (range)	6 (2–27)

Prior treatment for metastatic disease, n (%)
Trastuzumab	184 (100.0)
T-DM1	184 (100.0)
Pertuzumab	121 (65.8)
Other anti-HER2	100 (54.3)
Hormone therapy	90 (48.9)
Other systemic therapy	183 (99.5)

Best response to prior T-DM1 therapy, n (%)
CR	5 (2.7)
PR	35 (19.0)
SD	39 (21.2)
PD	66 (35.9)
Not evaluable	39 (21.2)

CR, complete response; ECOG PS, Eastern Cooperative Oncology Group performance status; HER2, human epidermal growth factor receptor 2; IHC, immunohistochemistry; ISH, in situ hybridization; PD, progressive disease; PR, partial response; SD, stable disease; T-DM1, trastuzumab emtansine; T-DXd, trastuzumab deruxtecan.

Data cutoff March 26, 2021.

All 184 patients received 1 or more dose of T-DXd.

HER2 status was centrally assessed on the most recent archival tissue according to the American Society of Clinical Oncology/College of American Pathologists guidelines.

Includes treated and asymptomatic brain metastases.