OBJECTIVES: To evaluate the cost-effectiveness of atezolizumab in combination with nab-paclitaxel in women with locally advanced or metastatic triple-negative breast cancer that cannot be treated surgically and whose tumors are PD-L1-positive in France.

METHODS: A partition survival model adapted to the French setting was used to estimate clinical outcomes and costs of atezolizumab + nab-paclitaxel, paclitaxel, capecitabine and bevacizumab + paclitaxel on a lifetime horizon. Costs and outcomes were discounted at 4%. Parametric functions were fitted to the phase III IMpassion130 trial data regarding progression-free survival (PFS) and overall survival (OS). PFS and OS of paclitaxel, capecitabine and bevacizumab + paclitaxel were estimated using a piecewise network meta-analysis as the proportional hazard assumption was violated for both PFS and OS in several trials of the network. As the network was disconnected, a matching-adjusted indirect comparison was used. Health state utilities were estimated from the Impassion130 trial using EQ-5D-5L mapped to EQ-5D-3L to apply French preference scores. Costs (2019) were calculated from a collective perspective. Probabilistic and deterministic sensitivity analyses were carried out to explore model assumption and parameter uncertainty.

RESULTS: Strategies were ranked based on total costs and quality-adjusted life years (QALYs) on the efficient frontier in increasing order: capecitabine, paclitaxel, bevacizumab + paclitaxel and atezolizumab + nab-paclitaxel. Bevacizumab + paclitaxel was extendedly dominated by atezolizumab + nab-paclitaxel. Compared to paclitaxel, the therapeutic combination atezolizumab + nab-paclitaxel was associated with a gain of 0.852 QALY (1.941 vs 1.089) and an incremental cost of €79,813 resulting in an incremental cost-utility ratio (ICUR) of €88,358/QALY.

CONCLUSIONS: Results of the present evaluation showed that atezolizumab + nab-paclitaxel is the most effective and the most costly strategy. The ICUR showed that atezolizumab + nab-paclitaxel seems to be a cost-effective strategy bringing substantial health benefit to the patients at an acceptable additional cost for the payer.