Impact of adding pertuzumab to trastuzumab plus chemotherapy in neoadjuvant treatment of HER2 positive breast cancer patients: a multicenter real-life HER2PATH study

Abstract

Aim To investigate the pathological complete response (pCR) achieved after neoadjuvant therapy with versus without adding pertuzumab (P) to trastuzumab (H) plus neoadjuvant chemotherapy (NCT) in HER2+ breast cancer (BC) patients in a real-life setting. Methods A total of 1528 female HER2+ BC patients who received NCT plus H with or without P were included in this retrospective real-life study. Primary endpoint was pCR rate (ypT0/Tis ypN0). Clinicopathological characteristics, event-free survival (EFS) time, and relapse rates were evaluated with respect to HER2 blockade (NCT-H vs. NCT-HP) and pCR. Results Overall, 62.2% of patients received NCT-H and 37.8% received NCT-HP. NCT-HP was associated with a significantly higher pCR rate (66.4 vs. 56.8%, p < 0.001) and lower relapse (4.5 vs. 12.2%, p < 0.001) in comparison to NCT-H. Patients with pCR had a significantly lower relapse (5.6 vs. 14.9%, p < 0.001) and longer EFS time (mean(SE) 111.2(1.9) vs. 93.9(2.7) months, p < 0.001) compared to patients with non-pCR. Patients in the NCT-HP group were more likely to receive docetaxel (75.0 vs. 40.6%, p < 0.001), while those with pCR were more likely to receive paclitaxel (50.2 vs. 40.7%, p < 0.001) and NCT-HP (41.5 vs. 32.1%, p < 0.001). Hormone receptor status and breast conservation rates were similar in NCT-HP vs. NCT-H groups and in patients with vs. without pCR. Invasive ductal carcinoma (OR, 2.669, 95% CI 1.596 to 4.464, p < 0.001), lower histological grade of the tumor (OR, 4.052, 95% CI 2.446 to 6.713, p < 0.001 for grade 2 and OR, 3.496, 95% CI 2.020 to 6.053, p < 0.001 for grade 3), lower T stage (OR, 1.959, 95% CI 1.411 to 2.720, p < 0.001) and paclitaxel (vs. docetaxel, OR, 1.571, 95% CI 1.127 to 2.190, p = 0.008) significantly predicted the pCR. Conclusions This real-life study indicates that adding P to NCT-H enables higher pCR than NCT-H in HER2+ BC, while pCR was associated with lower relapse and better EFS time.