A tumor-responsive nanostrategy for reducing the risk of immunotherapy-related myocarditis

Immune checkpoint blockade (ICB) therapy using anti-programmed cell death 1 (PD1) and cytotoxic T lymphocyte antigen 4 (CTLA4), either individual or in combination, has emerged as a pioneer in clinical immunotherapy for various human cancers. However, immune-related adverse effects (irAEs) remain the significant hindrances to their clinical development. In particular, immune-related myocarditis has emerged as a fatal adverse event with the highest fatality rate. For this purpose, we report herein the first example of uncoupling efficacy and myocarditis toxicity in checkpoint blockade cancer therapy. This efficient, yet highly safe access to ICB therapy was achieved by a simple nanoplatform that masked anti-PD1/CTLA4 antibodies to albumin via a ROS-cleavable linker. An in-depth investigation of the experimental autoimmune myocarditis (EAM) mouse model revealed the avoiding exacerbation of myocarditis of our nanomedicine. Notably, the on-demand release of antibodies at the tumor sites enables the combined checkpoint antibody activity. The present study uncouples the ICB efficacy and toxicity, and highlights the irresistible charm of TME-responsive nanoantibodies in clinical cancer immunotherapy, offering solutions to challenges in the advancement of TME-responsive drug delivery toward clinical application.