Enhanced Cancer Immunotherapy by Microneedle Patch-Assisted Delivery of Anti-PD1 Antibody.

Despite recent advances in melanoma treatment through the use of anti-PD-1 (aPD1) immunotherapy, the efficacy of this method remains to be improved. Here we report an innovative self-degradable microneedle (MN) patch for the sustained delivery of aPD1 in a physiologically controllable manner. The microneedle is composed of biocompatible hyaluronic acid integrated with pH-sensitive dextran nanoparticles (NPs) that encapsulate aPD1 and glucose oxidase (GOx), which converts blood glucose to gluconic acid. The generation of acidic environment promotes the self-dissociation of NPs and subsequently results in the substantial release of aPD1. We find that a single administration of the MN patch induces robust immune responses in a B16F10 mouse melanoma model compared to MN without degradation trigger or intratumoral injection of free aPD1 with the same dose. Moreover, this administration strategy can integrate with other immunomodulators (such as anti-CTLA-4) to achieve combination therapy for enhancing antitumor efficacy.

Synergistic Transcutaneous Immunotherapy Enhances Antitumor Immune Responses through Delivery of Checkpoint Inhibitors.

Despite the promising efficacy of immunoregulation in cancer therapy, the clinical benefit has been restricted by inefficient infiltration of lymphocytes in the evolution of immune evasion. Also, immune-related adverse events have often occurred due to the off-target binding of therapeutics to normal tissues after systematic treatment. In light of this, we have developed a synergistic immunotherapy strategy that locally targets the immunoinhibitory receptor programmed cell death protein 1 (PD1) and immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO) for the treatment of melanoma through a microneedle-based transcutaneous delivery approach. The embedded immunotherapeutic nanocapsule loaded with anti-PD1 antibody (aPD1) is assembled from hyaluronic acid modified with 1-methyl-dl-tryptophan (1-MT), an inhibitor of IDO. This formulation method based on the combination strategy of "drug A in carriers formed by incorporation of drug B" facilitates the loading capacity of therapeutics. Moreover, the resulting delivery device elicits the sustained release and enhances retention of checkpoint inhibitors in the tumor microenvironment. Using a B16F10 mouse melanoma model, we demonstrate that this synergistic treatment has achieved potent antitumor efficacy, which is accompanied by enhanced effective T cell immunity as well as reduced immunosuppression in the local site.