Advanced strategies for combinational immunotherapy of cancer based on polymeric nanomedicines

Although immunotherapy has revolutionized cancer therapy by providing efficient tumor growth suppression, long-term protection from recurrence as well as minimized side effects, the low response rate significantly limits the clinical application of immunotherapy in board types of solid tumors. In order to improve the therapeutic efficacy, conventional therapies including radiotherapy, chemotherapy, phototherapy and chemodynamic therapy are employed to combine with immunotherapy to elicit stronger antitumor immune responses. Polymer nanomedicines are frequently utilized in synergistic immunotherapy and other therapies owing to their tunable physiochemical properties, high drug loading capacity, ease of modification and low toxicity. With elaborate design and tailored properties, polymer nanomedicines can significantly enhance antitumor efficacy by enhancing tumor specificity, priming immune cells and amplifying immune responses in tumors. However, until now, there is no review solely dedicated to the comprehensive development of polymer-based platforms for combinational immunotherapy of cancers. Herein, this paper summarizes latest advances in the design, fabrication and application of polymer nanomedicines in combinational immunotherapy and traditional antitumor strategies including radiotherapy, chemotherapy, photothermal therapy, photodynamic therapy and other therapies. An outlook on the trajectory and potential challenges of polymer nanomedicines in bridging the gap between immunotherapy and conventional therapies is also discussed.