Exploring novel systemic therapies for pancreatic cancer: a review of emerging anti-PD-1/PD-L1 combination therapy.

Despite attempts to apply single therapy such as surgical treatment, chemotherapy, or radiotherapy, pancreatic cancer (PC) is still one of the most lethal solid tumors. Moreover, immune checkpoint inhibitors against PD-1/PD-L1, which have shown good efficacies against many other solid tumors, have not shown encouraging results in PC treatment. Therefore, some studies are evaluating the efficacies of combination therapies based on anti-PD-1/PD-L1 for PC. In this review, we summarized the emerging anti-PD-1/PD-L1 combination therapies for PC in these years. We realized that anti-PD-1/PD-L1-based combination therapies have the potential to be efficacious in PC treatment, and further relevant studies are needed. Moreover, we elucidated the reasons for the ineffectiveness of anti-PD-1/PD-L1 alone in PC treatment. We concluded that this was mainly because PC has an immunosuppressive tumor microenvironment and develops drug resistance during treatment. Anti-PD-1/PD-L1-based combination therapeutic regimens that alter the immunosuppressive tumor microenvironment and reduce the development of drug resistance in PC are summarized in this review, and we expect that these regimens will achieve good clinical application prospects.