Table 3 PI3K pathway activation and Efficacy of HER2-Targeted Drugs
From: PI3K pathway activation results in low efficacy of both trastuzumab and lapatinib
| Â | PI3KCA mutation | PTEN expression | PI3K pathway activation | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Â | Mutation (n = 7) | WT (n = 50) | P | Loss (n = 18) | WT (n = 39) | P | Activation (n = 22) | WT (n = 35) | P |
Lapatinib plus Capecitabine | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Overall response No.(%) | 1 (14.3%) | 12 (24%) | NS | 2 (11.1%) | 11 (28.2%) | NS | 2 (9.1%) | 11 (31.4%) | 0.050 |
Clinical benefit No. (%) | 3 (42.9%) | 29 (58%) | NS | 6 (33.3%) | 26 (66.7%) | 0.018 | 8 (36.4%) | 24 (68.6%) | 0.017 |
Median PFS months (95% CI) | 6 (2.7-9.3) | 6.5 (4.3-8.7) | NS | 5 (4.0-6.0) | 8 (5.6-10.4) | NS | 5 (3.5-6.6) | 8 (5.1-10.9) | NS |
Median OS months (95% CI) | 17 (2.5-31.5) | 17 (11.8-22.2) | NS | 19.5 | 15 | NS | 19.5 | 15 | NS |
First Trastuzumab Regimen | Â | Â | Â | Â | Â | Â | Â | Â | Â |
Median PFS months (95% CI) | 4.5 (0.7-8.3) | 8 (5.2-10.8) | NS | 6 (3.3-8.7) | 9 (7.1-10.9) | 0.024 | 4.5 (2.0-7.0) | 9 (7.6-10.4) | 0.013 |