Case Report: Toripalimab Combined With Anlotinib in a Patient With Metastatic Upper Tract Urothelial Carcinoma After Pembrolizumab Failure

Research progress on PD-1 and PD-L1 inhibitors in the treatment of metastatic urothelial carcinoma

Urothelial carcinoma (UC) is a very common malignant tumor. In the past few decades, platinum-based chemotherapy has been regarded as the standard recommended regimen for patients with metastatic urothelial carcinoma (mUC) who can receive either cisplatin or carboplatin. The emergence of immune checkpoint inhibitors (ICIs) brought some hope for possible treatments for mUC patients who were unfit for platinum therapy. ICIs drugs have emerged as new potential weapons to overcome UC in our lifetime. ICIs block the binding of programmed death-1 (PD-1) to programmed death-ligand 1 (PD-L1), leading to enhancement of the immune function of antitumor T cells. In the treatment of UC, ICIs show an apparent ascendancy and effectively enhance survival rates. With good tolerability and remarkable effects, ICIs have given thousands of patients hope. This article mainly shows the application of PD-1 and PD-L1 inhibitors in mUC.

Advances in the structural characterization of complexes of therapeutic antibodies with PD-1 or PD-L1

Antibody-based immune checkpoint blockade (ICB)-based therapeutics have become effective clinical applications for cancers. Applications of monoclonal antibodies (mAbs) to de-activate the PD-1-PD-L1 pathway could effectively reverse the phenotype of depleted activated thymocytes (T cells) to recover their anti-tumoral activities. High-resolution structures of the complexes of the therapeutic monoclonal antibodies with PD-1 or PD-L1 have revealed the key inter-molecular interactions and provided valuable insights into the fundamental mechanisms by which these antibodies inhibit PD-L1-PD-1 binding. Each anti-PD-1 mAb exhibits a unique blockade mechanism, such as interference with large PD-1-PD-L1 contacting interfaces, steric hindrance by overlapping a small area of this site, or binding to an N-glycosylated site. In contrast, all therapeutic anti-PD-L1 mAbs bind to a similar area of PD-L1. Here, we summarized advances in the structural characterization of the complexes of commercial mAbs that target PD-1 or PD-L1. In particular, we focus on the unique characteristics of those mAb structures, epitopes, and blockade mechanisms. It is well known that the use of antibodies as anti-tumor drugs has increased recently and both PD-1 and PD-L1 have attracted substantial attention as target for antibodies derived from new technologies. By focusing on structural characterization, this review aims to aid the development of novel antibodies targeting PD-1 or PD-L1 in the future.