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Research Focus

Checkpoint Blockade Response



Despite some success with checkpoint inhibitors, many patients do not respond or develop resistance to these immune therapies.


To find biomarkers that help determine which patients may respond to certain immunotherapies, allowing for more personalized treatment that maximizes the chance of success.

Checkpoint inhibitor agents that target the checkpoint blockade pathway have emerged as breakthrough cancer immunotherapy treatments in the last few years. For patients with skin, lung and other types of cancer, these drugs have given hope by adding years to their lives.

However, for a significant percentage of cancer patients, checkpoint inhibitors do not slow cancer down. For others, the treatments may work initially but fail to succeed over time due to the development of drug resistance.

The Parker Institute for Cancer Immunotherapy is developing several clinical trials to investigate the reasons behind checkpoint inhibitor resistance so that more cancer patients may benefit from these revolutionary treatments, and so that new treatments can be developed that can overcome causes of resistance.


The Parker Institute’s first clinical trial to examine checkpoint inhibitor resistance in skin cancer patients opened at Memorial Sloan Kettering Cancer Center, followed by other Parker Institute research sites: the University of California, Los Angeles, University of California, San Francisco, the University of Pennsylvania and The University of Texas MD Anderson Cancer Center.

Investigators are seeking to understand why certain melanoma patients progressed or did not respond to initial treatments with checkpoint inhibitor drugs targeting the PD-1 or CTLA-4 immune checkpoint blockade pathways. They will receive additional treatment with either one immune therapy or a combination of two. In addition, scientists will screen for biomarkers that may explain why some patients respond to the treatments while others may not.

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