Relationship between HER2 expression and efficacy with first-line trastuzumab emtansine compared with trastuzumab plus docetaxel in TDM4450g: a randomized phase II study of patients with previously untreated HER2-positive metastatic breast cancer

Table 1 Selected patient demographic and baseline characteristics by treatment arm

Characteristic	HT (n = 70)	T-DM1 (n = 67)
Median age, years (range)	52.0 (33 to 75)	55.0 (27 to 82)
World region, %
North America	28.6	31.3
Central and South America	28.6	23.9
Europe	42.9	44.8
Race, %
White	82.9	77.6
American Indian or Alaskan native	10.0	7.5
Black	4.3	4.5
Other or not available	2.9	10.4
ECOG PS, %
0	63.8^a	65.7
1	36.2^a	34.3
HER2 status by central laboratory, % ^b
HER2-positive	85.9	85.7
Normal	14.1	14.3
ER/PR status, %
ER-positive and/or PR-positive	54.3	49.3
ER-negative and PR-negative	41.4	47.8
ER and PR unknown	4.3	3.0
Stage at initial diagnosis, %
Stage I to III	68.1^a	58.2
Stage IV	29.0^a	34.3
Unknown	2.9^a	7.5
Number of distinct sites of involvement
1 to 2	49.3^a	35.8
>2	50.7^a	64.2
Lung or liver involvement. %
Yes	67.1	71.6
No	31.4	26.9
Unknown	1.4	1.5
Disease-free interval, %
≤24 months	64.3	59.7
>24 months	35.7	40.3
Prior treatment. %
Trastuzumab	27.1	17.9
Taxane	40.0	32.8
Anthracycline	48.6	44.8
Total number of prior chemotherapy agents, median (range)	3 (1 to 4)	3 (1 to 6)

Reproduced with permission from Hurvitz et al. [10]. ^aData were available for 69 patients in the HT arm. ^bCentral testing for HER2 status was performed for 64 patients in the HT arm and 63 patients in the T-DM1 arm. ECOG PS, Eastern Cooperative Oncology Group performance status; ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; HT, trastuzumab plus docetaxel; PR, progesterone receptor; T-DM1, trastuzumab emtansine.

ISSN: 1465-542X