Multicenter phase 2 trial of chemotherapy-free neoadjuvant pembrolizumab plus trastuzumab and pertuzumab for HER2-enriched early breast cancer

Accumulating evidence indicates that 30% to 40% of patients with HER2-positive early breast cancer (EBC) might achieve excellent outcomes without chemotherapy. The multicenter phase 2 WSG-KEYRICHED-1 trial in Germany evaluated twelve weeks of neoadjuvant pembrolizumab plus dual HER2 blockade (trastuzumab and pertuzumab) for HER2-enriched EBC. Twenty of 43 patients (47%) had a pathological complete response, which did not meet the primary endpoint. Eight percent of patients had grade 3 or 4 treatment-related adverse events. The authors conclude that WSG-KEYRICHED-1 highlights the potential of a short chemotherapy-free combination of pembrolizumab with dual anti-HER2 therapy among patients with HER2-enriched EBC.