GeparOLA: A randomized phase II trial to assess the efficacy of paclitaxel and olaparib in comparison to paclitaxel/carboplatin followed by epirubicin/cyclophosphamide as neoadjuvant chemotherapy in patients (pts) with HER2-negative early breast cancer (BC) and homologous recombination deficiency (HRD).

Abstract

506 Background: The efficacy and toxicity of olaparib in early BC pts with homologous DNA repair deficiency (here defined as HRD score high tumors +/- germline (g) or tumor (t) BRCA mutation) is not well described. GeparOLA investigates olaparib in HER2 negative early BC with HRD. Methods: GeparOLA (NCT02789332) randomized 102 pts to either paclitaxel 80 mg/m² weekly (Pw) plus olaparib 100 mg twice daily for 12 weeks (PwO n = 65) or Pw plus carboplatin (Cb) AUC2 weekly for 12 weeks (PwCb n = 37), both followed by EC. Randomization was stratified by hormone receptor-status (HR+ vs HR-) and age ( < 40 vs ≥40 years). Pts with untreated primary cT2 - cT4a-d or cT1c with either cN+ or pNSLN+ or triple negative or Ki-67 > 20% were included, with either g/t BRCA mutation and/or high HRD score. The primary endpoint is pathological complete response (pCR; ypT0/is ypN0). A one group χ2-test was planned to exclude the pCR rate of ≤55% in PwO→EC arm. Secondary endpoints are other pCR definitions, breast conservation rate, clinical and imaging response, tolerability and safety. Results: A total of 107 pts were randomized between 9/2016 and 7/2018; 106 started treatment. Median age was 47.0 years [range 25.0-71.0]; 36.2% of pts had cT1, 61.0% cT2, 2.9% cT3, and 31.8% cN-positive tumors; G3: 86.8%; Ki-67 > 20%: 89.6%; TNBC 72.6%; confirmed g /tBRCA 1/2 mutation: 60.4%. pCR rate with PwO was 55.1% (90%CI 44.5%-65.3%) vs PwCb 48.6% (90%CI 34.3%-63.2%). Analysis for the stratified subgroups showed higher pCR rates with PwO in the cohorts of pts < 40 years and HR+ pts Clinical trial information: NCT02789332. Conclusions: GeparOla could not exclude a pCR rate of ≤55% in the PwO arm. Subgroup analysis is hypothesis generating and need further confirmation.[Table: see text]