3. Subgroup analysis of progression-free survival, multivariate Cox regression analysis.

Variables	HR	95% CI	P
HR, hazard ratio; 95% CI, 95% confidence interval.
Lapatinib group vs. trastuzumab group	0.68	0.52−0.90	0.006
Age ≥45 years vs. <45 years	1.09	0.84−1.42	0.517
Hormone receptor status positive vs. negative	1.24	0.96−1.60	0.101
No. of metastatic sites ≤2 vs. >2	1.10	0.80−1.52	0.560
Brain metastases (yes vs. no)	0.91	0.67−1.24	0.544
Liver metastases (yes vs. no)	1.23	0.91−1.66	0.188
Visceral metastases (yes vs. no)	1.12	0.81−1.56	0.500
Duration of previous trastuzumab-containing regimen ≥6 months vs. <6 months first-line vs. second and third line	0.78	0.64−0.96	0.048