Association of phosphatase and tensin homolog low and phosphatidylinositol 3-kinase catalytic subunit alpha gene mutations on outcome in human epidermal growth factor receptor 2-positive metastatic breast cancer patients treated with first-line lapatinib plus paclitaxel or paclitaxel alone

Table 3 Summary of Cox regression model for OS with treatment, PIK3CA mutation, PTEN low, and interaction adjusting for stratification factors

Covariate	HR (95% CI)	Two-sidedPvalue
PIK3CA mutation ^a
Treatment (Lap + Pac/Pbo + Pac) (n = 171)	0.88 (0.53, 1.46)	0.611
HR status (negative/positive)	0.82 (0.55, 1.23)	0.343
Metastatic sites (visceral/nonvisceral only)	0.52 (0.30, 0.92)	0.024
PIK3CA mutation (yes/no)	2.24 (1.29, 3.88)	0.004
Treatment^a PIK3CA interaction	0.91 (0.41, 2.02)	0.809
PTEN low
Treatment (Lap + Pac/Pbo + Pac) (n = 355)	1.00 (0.67, 1.50)	0.998
HR status (negative/positive)	1.17 (0.89, 1.53)	0.256
Metastatic sites (visceral/nonvisceral only)	0.50 (0.33, 0.76)	0.001
PTEN low (yes/no)	1.16 (0.80, 1.69)	0.425
Treatment^a PTEN low interaction	0.62 (0.36, 1.07)	0.088

^aPatients with a PIK3CA indeterminate tumor status were excluded. CI, confidence interval; HR, hazard ratio; Lap, lapatinib; OS, overall survival; Pac, paclitaxel; Pbo, placebo; PIK3CA, phosphatidylinositol 3-kinase subunit alpha gene; PTEN, phosphatase and tensin homolog.

ISSN: 1465-542X