Neoadjuvant trastuzumab-pertuzumab plus endocrine versus chemotherapy in HR+/HER2+ EBC: survival analysis of WSG TP-II

Primary analysis of the multicenter phase 2 WSG TP-II trial found that among patients with HR-positive/HER2-positive early stage breast cancer (HR+ HER2+ eBC), the pathologic complete response (pCR) rate was superior with neoadjuvant once-weekly paclitaxel plus trastuzumab plus pertuzumab (CT-HP group; pCR rate 56.4%) compared to the pCR rate with endocrine therapy (ET) plus trastuzumab plus pertuzumab (ET-HP group; 23.7%). Five-year survival analysis has now been published. A total of 207 patients were randomized 1:1 to both groups; all patients received dual HER2 blockade in the adjuvant setting. At 5 years, the overall survival rate was 100% (95% 100.0-100.0) in the ET-HP group versus 97.9% (95.0-100.0) in the CT-HP group; the 5-year event-free survival-ductal carcinoma in situ rates were 92.1% (86.6-97.9) versus 94.8 (90.5-99.3), respectively; and the 5-year invasive disease-free survival rates were 97.7% (94.5-100.0) versus 79.8% (55.6-100.0), respectively. The authors conclude that patients with HR+ HER2+ eBC had excellent survival outcomes with de-escalated chemotherapy or ET in combination with HP in the neoadjuvant setting.