Pembrolizumab and salvage chemotherapy in EGFR T790M-positive non-small-cell lung cancer with high PD-L1 expression

Takehiro Tozuka,1 Masahiro Seike,1 Yuji Minegishi,1 Shingo Kitagawa,1 Tomomi Kato,1 Natsuki Takano,1 Kakeru Hisakane,1 Satoshi Takahashi,1 Kenichi Kobayashi,1 Takeru Kashiwada,1 Teppei Sugano,1 Susumu Takeuchi,1 Shinobu Kunugi,2 Rintaro Noro,1 Yoshinobu Saito,1 Kaoru Kubota,1 Akihiko Gemma1 1Department of Pulmonary Medicine and Oncology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan; 2Department of Analytic Human Pathology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan Abstract: Immuno-checkpoint inhibitors (ICI) have become an effective treatment option for non-small-cell lung cancer patients. However, ICI therapy was reported to be less effective in patients with epidermal growth factor receptor (EGFR) mutations than in those with wild-type EGFR. We report here that an non-small-cell lung cancer patient with the EGFR mutant T790M showed a programmed cell death ligand 1 (PD-L1) expression level that increased from 90% after eighth-line osimertinib therapy. He was treated with pembrolizumab as a ninth-line treatment, and attained stable disease. After the pembrolizumab therapy, he was treated with gemcitabine, which produced a good response despite being the 10th-line treatment. We should consider administering ICI and chemotherapy even to EGFR mutant patients after failure of EGFR tyrosine kinase inhibitor, especially in cases with high PD-LI expression. Keywords: programmed cell death ligand 1, epidermal growth factor receptor mutation, lung cancer, chemotherapy post immunotherapy