Reversal of resistance to chemotherapy following anti-programmed cell death-1 immunotherapy in metastatic lung adenocarcinoma: A case report

For metastatic non-small cell lung cancer with no epidermal growth factor receptor mutations or anaplastic lymphoma kinase gene rearrangements, programmed cell death-1 (PD-1) blockade is preferentially recommended post first-line chemotherapy. However, still many patients do not respond to these agents. After development of resistance to PD-1 blockade, further evaluation of chemotherapy regimen will be necessary. A 57-year old man had cough with minimal whitish expectoration. Computed tomography (CT) scans showed that he had an upper lobe mass of his left lung and multiple lymphadenectasis, including mediastinal and hilar lymph nodes, and also to the right intrapulmonary lymph nodes. The patient was diagnosed with adenocarcinoma after a biopsy was conducted on the upper lobe mass of his left lung. The patient received pemetrexed plus cisplatin (Pem-Cis) treatment for 6 cycles and sequential thoracic radiation as a therapeutic schedule. CT demonstrated a confirmed partial response after these treatments. Three months later, the tumors continued to grow. The patient received successive pemetrexed-based chemotherapy regimens; however, these regimens failed to stop tumor progression. The patient subsequently underwent 6 cycles of PD-1 mAb pembrolizumab treatment. Sensitivity of chemotherapy was restored, and the patient displayed a reduction in the size of enlarged mediastinal and hilar lymph nodes after 2 cycles of treatment with Pem-Cis, the initially used chemotherapy regimen. This outcome suggests that PD-1 blockade holds promise as a treatment strategy for reversion of chemotherapy resistance in refractory lung adenocarcinoma and warrants additional studies.