PD-L1 blockade by immune checkpoint inhibitors impairs sensitivity to osimertinib in EGFR-mutant non-small cell lung cancer cells.

In the previous studies, it was shown that osimertinib plus durvalumab did not achieve satisfactory efficacy, even inferior to osimertinib alone. We found that PD-L1 blockade impaired the efficacy of osimertinib in EGFR-mutant NSCLC cells despite the presence of the tumor microenvironment. Therefore, durvalumab has no synergistic effect on osimertinib, and combination therapy will not enhance the efficacy of osimertinib.