Outcomes of Immune Check Point Inhibitor Use in US Veterans With Pre-Existing Idiopathic Inflammatory Myopathies: Case Series and Literature Review

Our plain-English summary of Outcomes of Immune Check Point Inhibitor Use in US Veterans With Pre-Existing Idiopathic Inflammatory Myopathies: Case Series and Literature Review, by D. Krutko, S. Rubino, G.A. Kunkel, et al (ACR Open Rheumatology, 2026).

The study

• Authors: D. Krutko, S. Rubino, G.A. Kunkel, J.A. Walsh, J. Rojas, B.C. Sauer, S. Patel, G.W. Cannon, T.J. Braaten
• Journal: ACR Open Rheumatology
• Published: 2026;8(8):e90127
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: Our objective was to identify and describe the clinical characteristics and outcomes in patients with pre-existing idiopathic inflammatory myopathies (IIMs) in the Veterans Health Administration (VHA) treated with immune checkpoint inhibitors (ICIs).

Methods: All veterans receiving ICI infusions were identified. Patients with at least two International Classification of Disease codes for IIM before first ICI infusion underwent chart review to identify patients with confirmed IIM by American College of Rheumatology/EULAR criteria. The demographics, cancer diagnoses, laboratory findings, clinical course, and mortality rates were reported. IIM cases were also reviewed to determine if patients developed IIM flare following ICI treatment.

Results: We identified 29,539 veterans who received at least one ICI infusion in the VHA between June 6, 2011, and February 14, 2023. The eight patients with confirmed IIM before ICI treatment were mostly White men with an average age of 71.7 years at first ICI infusion. The IIM diagnoses were dermatomyositis in three patients, polymyositis in two, antisynthetase syndrome in two, and one rheumatoid arthritis (RA)/myositis overlap. Cancer diagnoses were lung (two), melanoma (two), head and neck (two), kidney/other urinary (one), and mesothelioma (one). Diagnosis of IIM was made on average 3.1 years before ICI treatment. One patient had an IIM flare after ICI. No IIM flares were identified in other patients.

Conclusion: Our findings show that an IIM flare after ICI therapy can occur, but most patients did not develop a flare. These observations suggest ICIs can be considered as an option in patients with cancer with IIM with shared decision-making and close monitoring.

© 2026 The Author(s). ACR Open Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.

In plain English

This brief report combined a case series from the US Veterans Health Administration (VHA) with a literature review. The authors identified 29,539 veterans who received at least one infusion of an immune checkpoint inhibitor, a type of cancer drug, between June 6, 2011, and February 14, 2023. Of these, 13 met screening criteria for a pre-existing idiopathic inflammatory myopathy (autoimmune myositis). Chart review confirmed 8: 3 dermatomyositis, 2 polymyositis, 2 antisynthetase syndrome and 1 RA/myositis overlap. All were men, and all but one Pacific Islander were White. Their cancers were lung (2), melanoma (2), head and neck (2), kidney/other urinary (1) and mesothelioma (1). Four received nivolumab and four pembrolizumab. One patient with dermatomyositis had a myositis flare after two doses and was treated with glucocorticoids and intravenous Ig. The other seven had no flares, and one patient had drug-induced colitis. The literature review found four previously reported cases, three of which flared. The authors concluded that these drugs can be considered in such patients with close monitoring. They noted that the small, all-male group makes it difficult to generalize the findings. The article does not discuss asbestos exposure.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective case series from VHA national databases with chart review, plus a literature review of previously published cases
• Who was studied: 29,539 US veterans who received at least one immune checkpoint inhibitor infusion in the VHA between June 6, 2011, and February 14, 2023. Of these, 13 met screening criteria for pre-existing idiopathic inflammatory myopathy and 8 were confirmed by EULAR/ACR criteria. All 8 were men with an average age of 71.7 years at first infusion; seven were White and one was Pacific Islander.
• Exposure: Immune checkpoint inhibitor cancer treatment: nivolumab (4 patients) or pembrolizumab (4 patients). Asbestos exposure is not addressed.
• Main results:
  • Among the 13 veterans who met screening criteria, 8 had confirmed idiopathic inflammatory myopathy: 3 dermatomyositis, 2 polymyositis, 2 antisynthetase syndrome and 1 RA/myositis overlap.
  • Primary cancers among the 8 patients were lung (2), melanoma (2), head and neck (2), kidney/other urinary (1) and mesothelioma (1).
  • In the 8 patients, the myositis diagnosis was made on average 3.1 years before the first checkpoint inhibitor treatment.
  • One patient with dermatomyositis had a myositis flare after two doses and was treated with glucocorticoids and intravenous Ig. In Table 1 this patient's cancer site is listed as pleura.
  • No myositis flares were identified in the other seven patients.
  • One patient had checkpoint inhibitor-induced colitis. No other patients developed immune-related adverse events.
  • According to the authors, the patient who flared died five months after the flare because of cancer progression.
  • The literature review found four previously published cases of pre-existing myositis treated with checkpoint inhibitors. Three of the four developed flares after one or two doses.
• The authors' conclusion: The authors concluded that checkpoint inhibitor use in patients with pre-existing myositis is not always associated with a flare, although flares can occur. They suggested that the therapy can be considered in such patients with close monitoring and shared decision-making.
• Limitations the authors state:
  • All patients were male, which reflects the VHA population.
  • There was little racial diversity: seven patients were White and one was Pacific Islander.
  • Only two checkpoint inhibitor drugs were used: pembrolizumab and nivolumab.
  • The time between cancer diagnosis and start of treatment varied widely.
  • Classification scores were minimal estimates, because some criteria were not adequately recorded in the health record.
  • Because the condition is rare, accurate incidence estimates may carry estimate error.
  • These limitations make it difficult to generalize the findings to other populations.

Topics

Medical terms in this study, explained in our Lexicon: Idiopathic, checkpoint inhibitors, Mesothelioma.

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