Atezolizumab and nab-paclitaxel for advanced breast cancer in Danish real-world patients.

Introduction: The Danish Medicines Council recommends that patients with estrogen receptor and human epidermal growth factor receptor 2-negative, programmed death-ligand 1 (PD-L1)-positive advanced breast cancer receive atezolizumab in combination with nab-paclitaxel. The approval was largely based on results from Impassion130 that showed a beneficial progression-free survival (PFS) and overall survival (OS) in PD-L1-positive patients who received atezolizumab and nab-paclitaxel.

Methods: We conducted a retrospective, population-based study that included patients who received atezolizumab for advanced breast cancer from October 2019 to September 2022. The primary endpoints were PFS and OS.

Results: This study included 74 advanced breast cancer patients. Their median age was 54.5 years, and 21 (28.4%) of the patients had de novo advanced disease. Most patients received first-line treatment with atezolizumab (83.8%). The median PFS was 6.0 months (95% confidence interval (CI): 4.7-8.4 months) and the median OS was 14.3 months (95% CI: 9.9-22.2 months). A total of 48 patients received atezolizumab and nab-paclitaxel in accordance with guidelines from the Danish Medicines Council.

Conclusions: This real-world study expectedly showed numerically lower survival outcomes than the phase III trial Impassion130, but met the standards of efficacy set by real-world studies in other countries. A need exists for increased attention to the criteria for receiving atezolizumab.

Funding: none.

Trial registration: The study was approved by the Oncological Committee of the DBCG, the Research Overview of the Capital (P-2022-828) and the Centre for Health of the Capital Region (R-22060674).