In vitro and in vivo synergistic efficacy of ceritinib combined with programmed cell death ligand-1 inhibitor in anaplastic lymphoma kinase-rearranged non-small-cell lung cancer.

Abstract

Both ceritinib (CER) and programmed cell death (PD)‐1/PD ligand‐1 (PD‐L1) have brought significant breakthroughs for anaplastic lymphoma kinase (ALK)‐rearranged non‐small‐cell lung cancer (NSCLC). However, the overall clinical efficacy of either CER or PD‐1/PD‐L1 inhibitor monotherapy has been limited to a large extent. In addition, the antitumor effect of combined CER and PD‐L1 inhibitor in ALK‐rearranged NSCLC is not fully understood. In H2228 cells, we examined the tumor killing effect of CER plus PD‐L1 inhibitor in vitro by quantitative RT‐PCR, flow cytometry, ELISA, western blot analysis, PBMC coculture system, and plasmid and transfection experiments. A Ba/F3 (EML4‐ALK‐WT) xenograft mouse model was also utilized to further evaluate the synergistic anticancer effects of CER and PD‐L1 inhibitor in vivo. The coculture system of PBMCs with H2228 cells promotes the expression of PD‐L1 and phospho‐ERK, and combined treatments facilitate lymphocyte proliferation and activation, inhibit PD‐L1 expression, and enhance lymphocyte cytotoxicity and cell death. In the in vivo NSCLC xenograft model, the volumes of tumors treated with CER and PD‐L1 inhibitor in combination were significantly smaller than those treated with CER or PD‐L1 alone. The relative tumor growth inhibitions were 84.9%, 20.0%, and 91.9% for CER, PD‐L1 inhibitor, and CER plus PD‐L1 groups, respectively. Ceritinib could synergize with PD‐1/PD‐L1 blockade to yield enhanced antitumor responses along with favorable tolerability of adverse effects. Ceritinib and PD‐L1 inhibitor combined produced a synergistic antineoplastic efficacy in vitro and in vivo, which provides a key insight and proof of principle for evaluating CER plus PD‐L1 blockade as combination therapy in clinical therapeutic practice.