The cost-effectiveness of atezolizumab in first-line for metastatic triple negative breast cancer is heavily linked to PD-L1 level.

The present analysis was conducted to assess the pharmacological costs of atezolizumab as first-line treatment in triple negative metastatic breast cancer (mBC). Pivotal phase III randomized controlled trial (RCT) was considered. Nine hundred and two patients were included. Differences in costs between the 2 arms (atezolizumab plus nabpaclitaxel versus placebo plus nab-paclitaxel) was 17 398 €, with a cost of 7564 €per month of OS-gain in the overall population and 2485 €per month of OS-gain in PD-L1-positive (≥1) population. Combining pharmacological costs of drugs with the measure of efficacy represented by the OS, atezolizumab could be considered cost-effective in first-line treatment for triple-negative mBC only in PD-L1-positive population, but a reduction of costs is mandatory.