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Immune-mediated diarrhea and colitis with normal biochemical, endoscopic and histologic findings: a retrospective
Malek Shatila1, Sharada Wali1, Carolina Colli Cruz1
1The University of Texas MD Anderson Cancer Center, Department of Gastroenterology, Hepatology, and Nutrition, Houston, TX (Malek Shatila, Sharada Wali*, Carolina Colli Cruz*, Krishnavathana Varatharajalu, Anusha Shirwaiker Thomas, Yinghong Wang).
Insights
Immune-mediated diarrhea and colitis (IMDC) without inflammation markers is linked to PD-1/PD-L1 inhibitors. These patients experience milder symptoms and fewer hospitalizations, though some still need immunosuppression.
Area of Science:
- Oncology
- Gastroenterology
- Immunology
Background:
- Immune-mediated diarrhea and colitis (IMDC) can occur with checkpoint inhibitors.
- A subset of patients presents with IMDC but lacks stool biomarker, endoscopic, or histologic evidence of inflammation.
- Understanding the treatment and outcomes for this specific IMDC group is limited.
Purpose of the Study:
- To describe the characteristics of IMDC patients with no inflammatory evidence.
- To clarify the role of immunosuppressive treatments in managing this IMDC subset.
- To investigate potential links between PD-1/PD-L1 inhibitors and this specific IMDC presentation.
Main Methods:
- Single-center, retrospective study.
- Inclusion criteria: patients treated with immune checkpoint inhibitors who developed clinical IMDC symptoms without inflammatory evidence (fecal calprotectin, endoscopy, histology).
- Study period: January 2010 to February 2024.
Main Results:
- 11.4% of IMDC patients (131/1151) showed no inflammation.
- These patients had higher PD-1/L1 agent exposure and less severe diarrhea, with lower hospitalization rates.
- Approximately 40% required immunosuppressive treatment, with no significant difference in symptoms or severity between those who did and did not receive it.
Conclusions:
- This is the first study on IMDC with normal inflammatory markers.
- PD-1/PD-L1 inhibition may predispose to this IMDC form, associated with milder outcomes.
- Despite milder presentation, immunosuppressive treatment is often necessary, and some patients may later develop colonic inflammation.
Background:
Immune-mediated diarrhea and colitis (IMDC) due to checkpoint inhibition infrequently presents with normal stool biomarkers and no endoscopic or histologic evidence of inflammation. Little is known about the treatment needs and outcomes of this subset of patients. We aimed to describe this entity and clarify the role of immunosuppressive treatments in its management.
Method:
This was a single-center, retrospective study of patients treated with immune checkpoint inhibitors who developed clinical symptoms of IMDC, with no evidence of inflammation based on fecal calprotectin or endoscopic/histologic evaluation, between January 2010 and February 2024.
Results:
Of 1151 patients with IMDC, 131 (11.4%) had no evidence of inflammation. These patients more frequently had PD-1/L1 agent exposure (P=0.019) and presented with less severe diarrhea than patients with evidence of inflammation (P<0.001). This group had a lower rate of hospitalization (P=0.003). Around 40% of patients with no evidence of inflammation required immunosuppressive treatment. There was no difference in clinical symptoms or severity between patients requiring immunosuppression and those who did not.
Conclusions:
Our study is the first to explore IMDC with no elevations in calprotectin and normal endoscopic/histologic findings. We found that PD-1/PD-L1 inhibition may predispose patients to developing this form of IMDC, which is associated with a lower severity of diarrhea, fewer hospitalizations and lower recurrence rates. Many patients still require immunosuppressive treatment, and a small subset later develop colonic inflammation. Future studies are needed to further elucidate the treatment needs and outcomes of this patient population.
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