Clinical Characteristics and Treatment of Immune-Related Adverse Events of Immune Checkpoint Inhibitors

Abstract

Immune checkpoint inhibitors (ICIs) have been changing the paradigm of cancer treatment. However, immune-related adverse effects (irAEs) have also increased with the exponential increase in the use of ICIs. ICIs can break up the immunologic homeostasis and reduce T-cell tolerance. Therefore, inhibition of immune checkpoint can lead to the activation of autoreactive T-cells, resulting in various irAEs similar to autoimmune diseases. Gastrointestinal toxicity, endocrine toxicity, and dermatologic toxicity are common side effects. Neurotoxicity, cardiotoxicity, and pulmonary toxicity are relatively rare but can be fatal. ICI-related gastrointestinal toxicity, dermatologic toxicity, and hypophysitis are more common with anti- CTLA-4 agents. ICI-related pulmonary toxicity, thyroid dysfunction, and myasthenia gravis are more common with PD-1/PD-L1 inhibitors. Treatment with systemic steroids is the principal strategy against irAEs. The use of immune-modulatory agents should be considered in case of no response to the steroid therapy. Treatment under the supervision of multidisciplinary specialists is also essential, because the symptoms and treatments of irAEs could involve many organs. Thus, this review focuses on the mechanism, clinical presentation, incidence, and treatment of various irAEs.

Keywords: Adverse events; Immune checkpoint inhibitor; Programmed cell death 1.

Figure 1. Enterocolitis related to immune checkpoint inhibitors. (A) Before steroid treatment, axial contrast computed tomography scan shows wall thickening and abnormal enhancement in intestine. (B) After steroid treatment, intestinal wall thickening and abnormal enhancement are reduced.

Figure 2. Inflammatory arthritis related to immune checkpoint inhibitors on both knees; axial contrast computed tomography scan show moderate joint effusion of both knees (right > left) with associated synovial thickening.

Figure 3. Exacerbation of psoriasis under immune checkpoint inhibitors; plaque psoriasis with silvery scales on trunk.