Immune thrombocytopenia in patients treated with immune checkpoint inhibitors

Immune checkpoint inhibitor-associated immune thrombocytopenia (ICI-ITP) has been described in case reports and small case series, but comprehensive data on its incidence, risk factors, clinical features, treatment, and outcomes are lacking. We reviewed medical records of all adults initiating ICI therapy between 2016 and 2023 at 29 US hospitals across 7 major cancer centers to identify patients with ICI-ITP. Multivariable logistic regression was used to identify risk factors, and Cox modeling was performed to assess the association between ICI-ITP, its severity, and mortality. Among 86 467 patients, ICI-ITP occurred in 214 (0.25%). Independent risk factors included lower baseline platelet count, combination ICI therapy, stage IV cancer, and additional immune-related adverse events. ICI-ITP occurred at a median of 8 weeks (interquartile range [IQR], 4-18) after ICI initiation, with a median nadir platelet count of 41 × 109/L (IQR, 17 × 109/L to 64 × 109/L). Patients were treated with glucocorticoids (n = 106 [49.5%]), immune globulin (n = 39 [18.2%]), and thrombopoietin receptor agonists (n = 29 [13.6%]). Recovery occurred in 161 patients (75.2%) at a median of 2.3 weeks (IQR, 1.0-5.3). Of 76 patients rechallenged with ICIs, 23 (30.3%) developed recurrent ICI-ITP. ICI-ITP and its severity were associated with higher all-cause mortality, with a nearly threefold increase in risk among patients with severe ICI-ITP than those without ICI-ITP (adjusted hazard ratio, 2.96 [95% confidence interval, 2.14-4.08]). These findings establish ICI-ITP as a rare but clinically significant complication of ICI therapy, provide, to our knowledge, the first large-scale description of its risk factors and clinical course, and underscore the importance of timely recognition and management.

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Journal
Blood
Published
2025-12-08
DOI
https://doi.org/10.1182/blood.2025031449
Citations
1
Primary Topic
Platelet Disorders and Treatments
Type
article
Field-Weighted Citation Impact
1.77
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Immune thrombocytopenia in patients treated with immune checkpoint inhibitors

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Immune thrombocytopenia in patients treated with immune checkpoint inhibitors

Mohamed Warsame, Rebecca L. Zon, Marina Heskel, Michael H. Kroll, Jodi V. Mones, David E. Leaf, Bolun Liu, Ronald S. Go, Rebecca Karp Leaf, Marina Beltrami Moreira, Elizabeth M. Corley, Kerry L. Reynolds, Carrie Sha, Trevor Jamison, Ethan Zhao, Guleid Hussein, Ilya Glezerman, Doris Soebbing, Julie‐Alexia Dias, Hanny T. Al-Samkari, Sahar Shahamatdar, Debbie Jiang, Patrick K. Juras, Mohamed I. Elsaid, Sumeet K. Yadav, Can Cui, Tushar Shenoy, Aaron Holmes, Arvind Suresh, Ellen K. Kendall, Dwight Hall Owen, Sarah Allison Kaunfer, Xingyi Li, Jennifer J. Huang, Tristan Lim, Andrew D. Leavitt, Alexa Mera, Neil Easton, Amy Spelman, Lavanya Durai, Maria Shabih, Sandhya Panch, Steven T. Hoge
article en
1 citations

Abstract

Immune checkpoint inhibitor-associated immune thrombocytopenia (ICI-ITP) has been described in case reports and small case series, but comprehensive data on its incidence, risk factors, clinical features, treatment, and outcomes are lacking. We reviewed medical records of all adults initiating ICI therapy between 2016 and 2023 at 29 US hospitals across 7 major cancer centers to identify patients with ICI-ITP. Multivariable logistic regression was used to identify risk factors, and Cox modeling was performed to assess the association between ICI-ITP, its severity, and mortality. Among 86 467 patients, ICI-ITP occurred in 214 (0.25%). Independent risk factors included lower baseline platelet count, combination ICI therapy, stage IV cancer, and additional immune-related adverse events. ICI-ITP occurred at a median of 8 weeks (interquartile range [IQR], 4-18) after ICI initiation, with a median nadir platelet count of 41 × 109/L (IQR, 17 × 109/L to 64 × 109/L). Patients were treated with glucocorticoids (n = 106 [49.5%]), immune globulin (n = 39 [18.2%]), and thrombopoietin receptor agonists (n = 29 [13.6%]). Recovery occurred in 161 patients (75.2%) at a median of 2.3 weeks (IQR, 1.0-5.3). Of 76 patients rechallenged with ICIs, 23 (30.3%) developed recurrent ICI-ITP. ICI-ITP and its severity were associated with higher all-cause mortality, with a nearly threefold increase in risk among patients with severe ICI-ITP than those without ICI-ITP (adjusted hazard ratio, 2.96 [95% confidence interval, 2.14-4.08]). These findings establish ICI-ITP as a rare but clinically significant complication of ICI therapy, provide, to our knowledge, the first large-scale description of its risk factors and clinical course, and underscore the importance of timely recognition and management.

BloodVol. 147(12)
Brigham and Women's Hospital (US), Mayo Clinic (US), Memorial Sloan Kettering Cancer Center (US), NewYork–Presbyterian Hospital (US), The University of Texas MD Anderson Cancer Center (US), Harvard University (US), City College of San Francisco (US), University of California, San Francisco (US), University of Washington (US), Cornell University (US), Jacksonville College (US), WinnMed (US), Massachusetts General Hospital (US), Fred Hutch Cancer Center (US), Presbyterian Hospital (US), Dana-Farber Cancer Institute (US), Mayo Clinic Health System (US), Global Cancer Institute (US), Mayo Clinic in Florida (US), The Ohio State University (US), University of San Francisco (US)
Openalex Percentile: Top 10%
Platelet Disorders and Treatments
1.77
DOISourceOpenAlex
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