Therapeutic proteins are playing increasingly important
roles in
treating numerous types of diseases. However, oral administration
of proteins, especially large ones (e.g., antibodies), remains a great
challenge due to their difficulties in penetrating intestinal barriers.
Herein, fluorocarbon-modified chitosan (FCS) is developed for efficient
oral delivery of different therapeutic proteins, in particular large
ones such as immune checkpoint blockade antibodies. In our design,
therapeutic proteins are mixed with FCS to form nanoparticles, lyophilized
with appropriate excipients, and then filled into enteric capsules
for oral administration. It has been found that FCS could promote
transmucosal delivery of its cargo protein via inducing transitory
rearrangement of tight junction associated proteins between intestinal
epithelial cells and subsequently release free proteins into blood
circulation. It is shown that at a 5-fold dose oral delivery of anti-programmed
cell death protein-1 (αPD1) or its combination with anti-cytotoxic
T-lymphocyte antigen 4 (αCTLA4) using this method could achieve
comparable antitumor therapeutic responses to that achieved by intravenous
injection of corresponding free antibodies in various types of tumor
models and, more excitingly, result in significantly reduced immune-related
adverse events. Our work successfully demonstrates the enhanced oral
delivery of antibody drugs to achieve systemic therapeutic responses
and may revolutionize the future clinical usage of protein therapeutics.