A Multistage-Responsive Antibody-Delivery Strategy to Improve Immunotherapy for NSCLC Brain Metastasis by Ultrasensitive Releasing and Tumor-Anchoring

Immune checkpoint blockade (ICB) therapy has emerged as a promising approach in clinical oncology. For brain metastases, the presence of the robust blood–brain barrier (BBB) and potential immune-related adverse events (irAEs) pose significant challenges. Here, a multistage-responsive antibody-delivery strategy is developed for non-small cell lung cancer (NSCLC) brain metastases, with the ultra-pH sensitivity borate bonds. The antibody-delivery nanoformulation (MB-aPDL1) is able to maintain the “silent state” in health tissue, cross the BBB/BTB by the GLUT1-mediated transcytosis, release the functionalized aPDL1 responsively, and promote the aPDL1 tumor-anchoring. In the in vivo tumor region, the MB-aPDL1 rapidly releases the activated BPA 6 -aPDL1, which successfully anchors to the tumor cells and improves the efficiency of ICB therapy. The two in vivo ICB therapy studies show a significant tumor growth inhibition from the MB-aPDL1 with an encouraging cure rate of 20% for the NSCLC brain metastases, due to enhanced immune response in tumor, commendably with less behavioral adverse reactions and liver damage. Taken together, this antibody-delivery strategy holds substantial potential for application in clinical treatment of brain metastases.