Background: T cell activation via the blockade of PD-1 pathway has been
recognized as an emerging drug target for cancer immunotherapy which provides a rationale
for clinical trials in cancer patients. The recent breakthrough approvals of T cell
checkpoint inhibitors targeting PD-1 pathway boost the era of immuno-oncology drugs.
Methods: The progress of PD-1 checkpoint inhibitor as a single agent in the field of
immuno-oncology is reviewed. Antibodies targting PD-1 and PD-L1 with regulatroy
approvals are discussed with the current coverage of indications. Other candidates in
clinical investigations are also summarized.
Results: Monoclonal antibodies that block protein-protein interactions between PD-1
and its ligand have shown the promise for the treatment of a variety of cancer types. The
fast growing family of PD-1 checkpoint inhibitors been observed both in regulatroy approvals
and clinical investigations.
Conclusion: The potential use of PD-1 checkpoint inhibitor alone or in combination
with other agents is substantial, and will further reveal the important role of PD-1 pathway
in immunomodulation and disease control.