A0374 - C-Reactive Protein Is Not a Reliable Biomarker to Assess the Severity and Response of Immune-Mediated Diarrhea and Colitis

Cynthia Liu, MD¹, Malek Shatila, MD², Antony Mathew, MD³, Antonio Pizuorno Machado, MD⁴, Austin R. Thomas, DO⁴, Hao Chi Zhang, MD⁵, Anusha S. Thomas, MD², Yinghong Wang, MD, PhD^2
1University of Texas MD Anderson Cancer Center, Houston, TX; ²MD Anderson Cancer Center, Houston, TX; ³The University of Texas Health Science Center at Houston, Houston, TX; ⁴University of Texas Health Science Center, Houston, TX; ⁵UT MD Anderson Cancer Center, Houston, TX

Introduction: C-reactive protein (CRP) is an inflammatory marker used to stratify and monitor disease in many inflammatory conditions. However, CRP level is not specific to any organ system and is widely influenced by various factors nonspecific to bowel inflammation. Fecal calprotectin has recently been shown as a specific biomarker in evaluating and monitoring immune-mediated diarrhea and colitis (IMDC) disease response. We aimed to study the utility of CRP as a predictor of disease severity and of response in IMDC.

Methods: We performed a retrospective cohort study of patients diagnosed with IMDC and had CRP measured at disease onset and after IMDC treatment with biologics between 7/01/2015 and 8/30/2021 at MD Anderson Cancer Center. Patient demographics, clinical characteristics, and IMDC data were collected and analyzed.

Results: Our sample of 128 patients had a median age of 67 years and majority were male (84%) and Caucasian (90%). Fifteen (12%) were initially treated with CTLA-4, 41 (32%) with PD-(L)1, and 71 (56%) with a combination of both prior to development of IMDC. At the time of IMDC diagnosis, there was no significant difference in CRP level by CTCAE grade of diarrhea (p=0.274), CTCAE grade of colitis (p=0.991), or endoscopic findings (p=0.385). While CRP levels decreased after IMDC treatment (p< 0.001), there remained no significant difference in CRP levels amongst those who did or did not achieve clinical remission (p=0.485), endoscopic remission (p=0.467), or histologic remission (p=0.303). There also was no significant relationship between CRP level and recurrence of IMDC (p=0.473).

Discussion: CRP level is not a favorable surrogate marker to provide accurate assessment on IMDC severity, treatment response, or disease recurrence. Despite the reduction of CRP levels observed following IMDC treatment, this finding is deemed non-specific and potentially confounded by concurrent clinical factors such as underlying malignancy status or non-colitis processes and treatments. Further studies are warranted to investigate the role of CRP in cancer patients with IMDC.


Disclosures:


Cynthia Liu, MD¹, Malek Shatila, MD², Antony Mathew, MD³, Antonio Pizuorno Machado, MD⁴, Austin R. Thomas, DO⁴, Hao Chi Zhang, MD⁵, Anusha S. Thomas, MD², Yinghong Wang, MD, PhD². A0374 - C-Reactive Protein Is Not a Reliable Biomarker to Assess the Severity and Response of Immune-Mediated Diarrhea and Colitis, ACG 2022 Annual Scientific Meeting Abstracts. Charlotte, NC: American College of Gastroenterology.