AACR17: Immunotherapy efficacy may be influenced by the patient’s immune system

According to the early results of a study from researchers at the University of Pittsburg Cancer Institute (UPCI) (PA, US), the findings of which were presented at The American Association of Cancer Research Annual Meeting 2017 (held 1-5 April 2017, DC, US), variations in the levels of particular immune cells in cancer patients may be associated with how well they respond to immunotherapy.

The research was an extension of the recently completed phase III clinical trial, CheckMate 141.
Checkmate 141, which was co-chaired by Robert Ferris (UPCI, US), demonstrated that the checkpoint inhibitor, nivolumab, significantly increased survival and resulted in fewer adverse events in patients with recurrent head and neck cancer.

As the treatment was not equally as effective in all the patients, however, Ferris and colleagues sought to discoverer whether differences in patients’ immune system profiles may be associated with the variations in responses to immunotherapy.

The team demonstrated that longer overall survival rates and an increased likelihood of response to nivolumab was associated with high levels of tumor-associated immune cells that expressed PD-L1 protein. Tumor-associated immune cells, which are tumor-infiltrating cells, are thought to play a crucial role in tumor growth.

Researchers also noted that when testing blood samples taken prior to the patients beginning the immunotherapy course, patients with elevated levels of circulating cytotoxic CD8 T cells and reduced levels of regulatory T cells were associated with a more favorable response to treatment.

“Our study shows that immune cells in the microenvironment around the tumor could play a critical role in how patients respond to immunotherapy. By determining the nature of these cells and how they are affected by treatments, we may be able to significantly improve the effectiveness of current therapies and help a greater number of patients,” stated Ferris.

UPMC press release: www.upmc.com/media/NewsReleases/2017/Pages/ferris-aacr17.aspx