The Nature letter published results showing that the monoclonal antibody targeting PD-1 had antitumor activity, but more importantly, the response was greater in patients overexpressing the PD-L1 receptor, thereby opening the doors for targeted therapy.
Treatment with an immune checkpoint inhibitor led to consistent responses across multiple types of cancer, particularly in patients with suppressed immune systems that appeared to be "reinvigorated" by the therapy, investigators reported.
Response rates of 20% to 25% were seen in patients with advanced cancers, including lung, kidney, and head and neck cancers, as well as melanoma. The overall response to the engineered antibody MPDL3280A increased to 46% in patients whose tumors exhibited overexpression of programmed death-ligand 1, a protein associated with immune suppression in multiple types of cancer, as reported a research letter in Nature.
The antitumor activity was encouraging, but the identification of markers predictive of response could prove to be equally important if not more so, according to Roy S. Herbst, MD, PhD, of the Yale Cancer Center.
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