Real-life analysis of pathologic complete response with neoadjuvant trastuzumab plus taxane with or without pertuzumab therapy in HER2 positive locally-advanced breast cancer (HER2PATH Study).

Abstract

e12610 Background: Studies in HER2+ locally-advanced breast cancer (LABC) patients with neoadjuvant dual HER2 blockage therapy demonstrated high rates of pathologic complete response (pCR). This study evaluates neoadjuvant chemotherapy (NCT) plus trastuzumab (H) with or without pertuzumab (P) therapy with a nation-wide real world setting. Methods: In this study, 1528 female HER2+ LABC patients’ data received NCT plus H with or without P were collected retrospectively from 21 centers. Ethics committee approved the study (NCT04765124). Primary end point was pCR rate (ypT0/Tis ypN0 in the current AJCC staging system). Results: Of the 1528, 951 (62.2%) were received NCT-H, 577 (37.8%) were received NCT-HP, follow-up durations were 30 months and 15 months, median ages were similar between 2 groups (47 years, range: 20-81 and 47 years, range 22-88, respectively). According to the menopausal and hormone receptor status 60% and 53.7% of patients were classified as premenopausal, 56% and 57.8% as estrogen receptor positive and 46.2% and 47.2% as progesterone receptor positive respectively at NCT-HP and NCT-H groups. Despite the patients at NCT-HP group mostly received docetaxel (75%), NCT-H group received weekly paclitaxel (59.4%) as taxane (p<0.001). pCR rate for patients treated with NCT-HP was significantly better than that for patients received NCT-H (66.4% vs. 56.8%, respectively, p<0.001) and there were not any statistical difference according to hormone receptor status. Two-years event-free survival (EFS) rates were 93.5% and 93.2% for NCT-HP and NCT-H groups, respectively (p=0.655), however, two years EFS rate was statistically significant in patients who achieved pCR compared to those who did not achieve pCR (95.1% vs. %90.6, p<0.001). There was not any toxicity leading to death. Conclusions: Our analysis of this real world data shows higher rates of pCR than in clinical trials, also adding pertuzumab to NCT-H demonstrates higher pCR rates and EFS rates compared with NCT-H in patients with HER2+ LABC.