Immune thrombocytopenia in patients treated with immune checkpoint inhibitors

R Rebecca K. Leaf (Department of Medicine, Massachusetts General Hospital, Boston) J Jodi V. Mones (3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY) T Tushar Shenoy (4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA) M Mohamed Warsame (5Department of Hospital Internal Medicine, Mayo Clinic Health System, Mankato, MN) M Marina Beltrami-Moreira (6Division of Hematology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH) S Sandhya Panch (7Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA) A Andrew D. Leavitt (9Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA) R Rebecca L. Zon (2Harvard Medical School, Boston, MA) E Ellen K. Kendall (12Department of Medicine, Massachusetts General Hospital, Boston, MA) S Sahar Shahamatdar (12Department of Medicine, Massachusetts General Hospital, Boston, MA) T Tristan L. Lim (12Department of Medicine, Massachusetts General Hospital, Boston, MA) C Can Cui D Debbie Jiang (1Division of Hematology and Oncology, Mass General Brigham Cancer Institute, Boston, MA) S Sarah A. Kaunfer (4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA) L Lavanya Durai (4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA) S Steven T. Hoge (4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA) J Julie-Alexia Dias (4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA) C Carrie Sha (3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY) A Aaron N. Holmes (3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY) N Neela Easton (3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY) E Elizabeth M. Corley (3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY) E Ethan Zhao (3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY) X Xingyi Li A Amy Spelman (15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX) C Christina Briggs Amos (15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX) D Doris Soebbing (15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX) M Maria Shabih (15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX) T Trevor Jamison (15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX) B Bolun Liu (5Department of Hospital Internal Medicine, Mayo Clinic Health System, Mankato, MN) G Guleid Hussein (5Department of Hospital Internal Medicine, Mayo Clinic Health System, Mankato, MN) S Sumeet Yadav (5Department of Hospital Internal Medicine, Mayo Clinic Health System, Mankato, MN) M Mohamed I. Elsaid D Dwight H. Owen A Alexa Meara (17Division of Medical Oncology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH) P Patrick K. Juras (18Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH) A Arvind Suresh M Marina Heskel (10Department of Medicine, University of California San Francisco, San Francisco, CA) J Jennifer J. Huang (7Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA) I Ilya G. Glezerman (19Renal Service, Memorial Sloan Kettering Cancer Center, New York, NY) R Ronald S. Go (9Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN) K Kerry L. Reynolds (1Division of Hematology and Oncology, Mass General Brigham Cancer Institute, Boston, MA) H Hanny Al-Samkari (Department of Medicine, Massachusetts General Hospital, Boston) M Michael H. Kroll (15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX) D David E. Leaf (Division of Renal Medicine, Brigham and Women’s Hospital, Boston)

Abstract

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.

Article Details

Journal Blood
Volume / Issue Vol. 147, Issue 12
Published March 19, 2026
Pages 1351-1364
ISSN 0006-4971
Publisher Elsevier BV

Journal Info

Blood

Elsevier BV

ISSN: 0006-4971 Health Sciences

Authors (44)

R

Rebecca K. Leaf

Department of Medicine, Massachusetts General Hospital, Boston

J

Jodi V. Mones

3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY

T

Tushar Shenoy

4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA

M

Mohamed Warsame

5Department of Hospital Internal Medicine, Mayo Clinic Health System, Mankato, MN

M

Marina Beltrami-Moreira

6Division of Hematology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH

S

Sandhya Panch

7Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA

A

Andrew D. Leavitt

9Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA

R

Rebecca L. Zon

2Harvard Medical School, Boston, MA

E

Ellen K. Kendall

12Department of Medicine, Massachusetts General Hospital, Boston, MA

S

Sahar Shahamatdar

12Department of Medicine, Massachusetts General Hospital, Boston, MA

T

Tristan L. Lim

12Department of Medicine, Massachusetts General Hospital, Boston, MA

C

Can Cui

D

Debbie Jiang

1Division of Hematology and Oncology, Mass General Brigham Cancer Institute, Boston, MA

S

Sarah A. Kaunfer

4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA

L

Lavanya Durai

4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA

S

Steven T. Hoge

4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA

J

Julie-Alexia Dias

4Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA

C

Carrie Sha

3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY

A

Aaron N. Holmes

3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY

N

Neela Easton

3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY

E

Elizabeth M. Corley

3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY

E

Ethan Zhao

3Hematology Service, Memorial Sloan Kettering Cancer Center, New York, NY

X

Xingyi Li

A

Amy Spelman

15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX

C

Christina Briggs Amos

15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX

D

Doris Soebbing

15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX

M

Maria Shabih

15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX

T

Trevor Jamison

15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX

B

Bolun Liu

5Department of Hospital Internal Medicine, Mayo Clinic Health System, Mankato, MN

G

Guleid Hussein

5Department of Hospital Internal Medicine, Mayo Clinic Health System, Mankato, MN

S

Sumeet Yadav

5Department of Hospital Internal Medicine, Mayo Clinic Health System, Mankato, MN

M

Mohamed I. Elsaid

D

Dwight H. Owen

A

Alexa Meara

17Division of Medical Oncology, Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH

P

Patrick K. Juras

18Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, Columbus, OH

A

Arvind Suresh

M

Marina Heskel

10Department of Medicine, University of California San Francisco, San Francisco, CA

J

Jennifer J. Huang

7Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA

I

Ilya G. Glezerman

19Renal Service, Memorial Sloan Kettering Cancer Center, New York, NY

R

Ronald S. Go

9Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN

K

Kerry L. Reynolds

1Division of Hematology and Oncology, Mass General Brigham Cancer Institute, Boston, MA

H

Hanny Al-Samkari

Department of Medicine, Massachusetts General Hospital, Boston

M

Michael H. Kroll

15Section of Hematology, The University of Texas MD Anderson Cancer Center, Houston, TX

D

David E. Leaf

Division of Renal Medicine, Brigham and Women’s Hospital, Boston