Atezolizumab and nab-paclitaxel for advanced triple-negative breast cancer in real-world practice

Introduction . Advances in molecular biology and biotechnology have enhanced the understanding of triple-negative breast cancer (TNBC) biology and facilitated the identification of patient subgroups that may potentially benefit from novel therapeutic approaches. Objective . The aim of this study is to evaluate the efficacy of the combination of atezolizumab and nab-paclitaxel in patients with locallyadvanced/metastatic TNBC in real-world clinical practice in the Russian Federation. Methods . This retrospective multicenter study included 65 patients with metastatic TNBC who received the atezolizumab and nab-paclitaxel in the second line of treatment and patients with early progression following neoadjuvant/adjuvant chemotherapy (≤12 months, primary resistance population) from October 2019 to September 2023 in routine clinical practice. Results. At the median follow-up of 11.5 months the median progression-free survival (mPFS) was 11.43 months (95 % CI, 6.59–16.28) in the ITT population. There was only factor associated with worsened mPFS – recurrence-free interval of ≤12 months following anthracycline/taxane-based neoadjuvant/adjuvant chemotherapy. mPFS was 15.8 months for primary metastatic or anthracycline/taxane-sensitive TNBC vs. 6.4 months for primary resistance population (OR 0.52, 95 % CI 0.54–0.97; p=0.03). A trend towards improved PFS was observed in the BRCA1/2 wt subgroup and patients with objective response. The mPFS for BRCA1/2 wt patients was 13.9 months vs. 5.6 months for BRCA1/2 mut patients (p=0.14). mPFS in patients with an objective response was 21.9 months vs 13.9 months in those without an objective response (p=0.63). Conclusions . This analysis represents the first multicenter study evaluating the efficacy of the combination of atezolizumab and nab-paclitaxel in real-world clinical practice in Russian population. The combination allows for an objective response rate of 20 % and mPFS of 11.43 months for patients as in the second line of treatment as with primary resistance.