Delivery Strategies for Immune Checkpoint Blockade

Immune checkpoint blockade, which blocks the regulatory pathways that express on immune cells to improve antitumor immunological responses, is becoming one of the most promising approaches for antitumor therapy. This therapy has achieved important clinical advancement and provided a new opportunity against a variety of cancers. However, limitations of checkpoint inhibitors application, including the risk of autoimmune disease, low objective response rates, and high cost, still largely affect their broad applications in patients. Therefore, it is desirable to seek effective delivery methods to further enhance the therapeutic efficacy and reduce drawbacks of immune checkpoint blockade. This brief review summarizes strategies to increase the antitumor immunity, including the local and targeted delivery of checkpoint inhibitors, and a combination of different checkpoint inhibitors or with other therapeutic treatments.