Remarkable response to combined immunochemotherapy in patients with metastatic triple-negative breast cancer

Background: Progress in immunotherapy (IT) has shifted treatment paradigms for multiple malignancies. In March 2019, the combination of nab-paclitaxel and atezolizumab was approved by the US FDA for patients with PD-L1 positive metastatic triple-negative breast cancer based on positive results of the Impassion130 trial. Although numerous studies have examined the prognostic role of PD-L1, the value of this test remains controversial. Results: Here, we presented the cases of three heavily pretreated women with metastatic triple-negative breast cancer who exhibited remarkable responses to combined IT and chemotherapy despite undetectable PD-L1. Conclusion: In our opinion, the current FDA-approved assessment for PD-L1 expression is a reasonable tool for deciding whether to start IT. However, because this approach has many limitations, patients with undetectable PD-L1 expression should still be considered for IT.