The WSG-ADAPT-HER2+/HR study showed good survival rates in patients with a pathological complete response after 12 weeks of trastuzumab plus pertuzumab with or without weekly paclitaxel. Omitting further chemotherapy did not affect invasive disease-free survival in patients with a pathological complete response.
The aim of WSG-ADAPT-HER2+/HR- was to define an early response biomarker to identify a subset of patients with HER2+ HR early breast cancer and a strong response to anti-HER2 therapy who can safely withhold chemotherapy. Patients were randomized 5:2 to 12 weeks of trastuzumab+pertuzumab or trastuzumab+pertuzumab plus paclitaxel. The primary objective was to compare the proportion of patients with a pathological complete response to surgery between early responders in the trastuzumab+pertuzumab group versus all patients (regardless of early response) in the trastuzumab+pertuzumab plus paclitaxel group. This primary endpoint has been reported previously; now the 5-year survival data were presented.
Between March 2014 and October 2015, 134 patients were randomized. The median follow-up in survivors was 59.9 months (IQR 53.4-61.4). There were no significant survival differences between the groups. In the trastuzumab+pertuzumab plus paclitaxel group and in the trastuzumab+pertuzumab group, the 5-year survival rates were 98 and 87 for invasive disease-free survival, respectively (HR 0.32; p = 0.15); 98 and 89 for recurrence-free survival (HR 0.41; p = 0.25); 100 and 95 for locoregional recurrence-free survival (HR 0.41; p = 0.43); 98 and 92 for distant disease-free survival (HR 0.35; p = 0.36) and 98 and 94 for overall survival (HR 0.41; p = 0.43). In addition, a pathological complete response was associated with a better invasive disease-free survival (HR 0.14; p = 0.011).
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