NIS2+^TM, an optimisation of the blood-based biomarker NIS4^? technology for the detection of at-risk NASH: A prospective derivation and validation study

Background & Aims: NIS4((R)) is a blood-based non-invasive test designed to effectively rule in/rule out at-risk non-alcoholic steatohepatitis (NASH), defined as non-alcoholic fatty liver disease activity score >= 4 and significant fibrosis (stage >= 2), among patients with metabolic risk factors. Robustness of non-invasive test scores across characteristics of interest including age, type 2 diabetes mellitus, and sex, and optimised analytical aspects are critical for large-scale implementation in clinical practice. We developed and validated NIS2+(TM), an optimisation of NIS4((R)), specifically designed to improve score robustness. Methods: A well-balanced training cohort (n = 198) included patients from the GOLDEN-505 trial. The validation (n = 684) and test (n = 2,035) cohorts included patients from the RESOLVE-IT trial. Well-matched subgroups were created to avoid potential confounding effects during modelling and analysis of score robustness. Models were trained using logistic regressions for at-risk NASH detection and compared using Bayesian information criteria. Performance of NIS2+(TM) was compared with that of NIS4((R)), Fibrosis-4, and alanine aminotransferase using area under the receiver operating characteristic curve, and robustness was analysed through score distribution. Results: Using the training cohort to compare all combinations of NIS4((R)) biomarkers, NIS2 (miR-34a-5p, YKL-40) was identified as the best combination of parameters. To correct for the sex effect on miR-34a-5p (validation cohort), sex and sex * miR-34a-5p parameters were added, creating NIS2+(TM). In the test cohort, NIS2+(TM) exhibited a statistically higher area under the receiver operating characteristic curve (0.813) vs. NIS4((R)) (0.792; p = 0.0002), Fibrosis-4 (0.653; p < 0.0001), and alanine aminotransferase (0.699; p < 0.0001). NIS2+(TM) scores were not affected by age, sex, BMI, or type 2 diabetes mellitus status, providing robust clinical performances irrespective of patient characteristics. Conclusion: NIS2+(TM) constitutes a robust optimisation of NIS4((R)) technology for the detection of at-risk NASH.