Therapies that activate the immune system through blocking the binding of programmed death ligand 1 (PD-L1) present on tumors and PD-1 (programmed death 1) present on activated immune cells are revolutionizing the care for cancer patients. These therapies work by inhibiting negative regulators of the immune system thereby decreasing a tumor's ability to evade the immune system. The side effects of anti-PD-1/PD-L1 therapies are generally mild and as expected are related to autoimmune reactions. Two of the most common side effects of anti-PD-1/PD-L1 therapies include rash and pruritus occurring in ~20% of patients. While the rash is generally recognized to be immune-mediated, the exact mechanisms of the rash remain unclear. Herein, we report three cases of lichenoid dermatitis in three patients treated with MK-3475 (anti-PD-1) that were characterized with marked T-cell infiltrates with few PD-1-positive cells. The rashes in all three patients were relatively mild allowing treatment to continue despite the rashes.
- Received July 14, 2014.
- Revision received August 20, 2014.
- Accepted September 9, 2014.
- Copyright © 2014, American Association for Cancer Research.