Autoimmune complications of immunotherapy: pathophysiology and managementBMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m736 (Published 06 April 2020) Cite this as: BMJ 2020;369:m736
- Karmela K Chan, assistant professor of medicine,
- Anne R Bass, professor of clinical medicine
- Correspondence to A Bass
Immune checkpoint inhibitors (ICIs) are monoclonal antibodies that target inhibitory molecules, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), or its ligand, programmed cell death protein ligand 1 (PD-L1), and lead to immune activation in the tumor micro-environment. ICIs can induce durable treatment responses in patients with advanced cancers, but they are commonly associated with immune related adverse events (irAEs) such as rash, colitis, hepatitis, pneumonitis, and endocrine and musculoskeletal disorders. Almost all patients experience some form of irAE, but high grade irAEs occur in approximately half of those on combination therapy (eg, anti-CTLA-4 plus anti-PD-1), and up to one quarter receiving ICI monotherapy. Fatal irAEs occur in approximately 1.2% of patients on CTLA-4 blockade and 0.4% of patients receiving PD-1 or PD-L1 blockade, and case fatality rates are highest for myocarditis and myositis. IrAEs typically occur in the first three months after ICI initiation, but can occur as early as one day after the first dose to years after ICI initiation. The mainstay of treatment is with corticosteroids, but tumor necrosis factor inhibitors are commonly used for refractory irAEs. Although ICIs are generally discontinued when high grade irAEs occur, ICI discontinuation alone is rarely adequate to resolve irAEs. Consensus guidelines have been published to help guide management, but will likely be modified as our understanding of irAEs grows.
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Competing interests: The BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the following other interests: none.
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Contributorship statement and guarantor: Drs Bass and Chan contributed equally to drafting the first draft of this manuscript. Dr Bass was responsible for overall content and final edits, and serves as the guarantor.
Provenance and peer review: commissioned; externally peer reviewed.