Table I. Baseline patient characteristics.

Patient Characteristics (n = 24)	Total number with (range) for age and (percentages) for others
Age, y (range)	56 (39–69)
Sex, n (%)
Female	24 (100)
Race, n (%)
Black	2 (8.3)
White	22 (91.7)
Hormone receptor status, n (%)
Positive	20 (83.3)
Negative	4 (16.7)
HER2 receptor status, n (%)
1+ IHC	2 (8.3)
2+ IHC	8 (33.3)
Not amplified by FISH	4
FISH not performed	2
FISH amplified	2
3+ IHC	14 (58.3)
Visceral metastases, n (%)
Yes	19 (79.2)
No	5 (20.8)
CNS metastases, n (%)
Yes	2 (8.3)
No	22 (91.7)
Prior lines of chemotherapy in the advanced setting, n (%)
0	8 (33.3)
1	11 (45.8)
2	4 (16.7)
3+	1 (4.2)
Prior trastuzumab
Yes	14 (58.3)
No	10 (41.7)

Assessments included hormone receptor positivity, presence of visceral metastases, prior lines of chemotherapy, use of trastuzumab, and/or previous HER2-directed therapies. Data exclude the two patients who died before receiving treatment on trial.