Disruption of the programmed cell death protein 1 (PD-1) pathway with immune checkpoint inhibitors represents a major breakthrough in the treatment of non-small cell lung cancer. We hypothesized that a combined inhibition of C5a/C5aR1 and PD-1 signaling may have an antitumor synergistic effect. RMP1-14 antibody was used to block PD-1 and an L-aptamer to inhibit signaling of complement C5a with its receptors. Using syngeneic models of lung cancer we demonstrate that the combination of C5a and PD-1 blockade markedly reduces tumor growth and metastasis, and leads to prolonged survival. This effect is accompanied by a negative association between the frequency of CD8 T cells and myeloid-derived suppressor cells (MDSCs) within the tumors, which may result in a more complete reversal of CD8 T-cell exhaustion. Our study provides support for the clinical evaluation of anti-PD-1 and anti-C5a drugs as a novel combination therapeutic strategy for lung cancer.
- Received October 20, 2016.
- Revision received March 8, 2017.
- Accepted March 10, 2017.
- Copyright ©2017, American Association for Cancer Research.