The precious study: a prospective, observational study of cd8+ biomarker based prognostic test in north american ibd patients

Abstract BACKGROUND The clinical course of IBD varies considerably among patients1. One barrier to personalized medicine in IBD is the lack of a reliable prognostic assay that can be used at diagnosis to guide effective therapy for each patient, to optimize clinical outcomes and minimize complications. To address this need, a whole-blood qPCR-based prognostic assay was developed to divide IBD patients into two subgroups2. This transcriptional signature yields CD8 T-cell exhaustion level data that correlated with disease outcomes among IBD patients in UK2. Here, we aimed to determine if this prognostic assay could stratify an ethnically diverse North American cohort of IBD patients at diagnosis into low and high-risk subgroups. METHODS PRECIOUS (Predicting Crohn’s & Colitis Outcomes in the United States) is a multi-centre, observational, double-blinded study of patients with active IBD, who are not receiving systemic steroids, immunomodulator, advanced small molecules or biologics. The study is recruiting up to 200 patients between 16-80 years of age, from 14 centres across the US and Canada. Patients are prospectively followed for >12 months after enrolment to monitor disease course, including the requirement for IBD-related surgery or treatment escalations. Patients and clinicians are blinded to the biomarker results and patients are treated according to local practice. RESULTS Of 120 patients recruited to date, 86 have reached the 12-month follow-up timepoint (Table 1). Of the 102 patients with complete race and ethnicity data (Table 1), 63.5% are non-Hispanic Whites, 13.7% identified as Hispanic/Latino, 11.8% Asian and 9.8% Black/African American. Biomarker results were obtained for 80 (88.8%) of the 90 samples tested to date – 10 (11.1%) of samples failed quality control. Of these 80 results, 38 patients (47.5%) were identified as high risk for disease progression and 42 (52.5%) as low risk – a similar breakdown to that seen in the UK cohort2. DISCUSSION This is the first trial of a prognostic biomarker for patients with CD and UC in North America. This patient population was significantly more diverse than the UK cohort which had ~98% White. This diversity is not generally reflected in clinical trials performed in the United States in which approximately 90% of participants for all conditions are White whereas non-Hispanic Whites represent approximately 60% of the U.S. population. 4,5. Our enrolment of only 63.5% non-Hispanic White subjects speaks to our targeted efforts to recruit a representative level of diversity into our study population to that represents the diversity of patients with IBD that are being diagnosed globally6.