ORLANDO – Changes in serum levels of cytokeratin fragments appear to reflect changes in liver histology in patients with nonalcoholic steatohepatitis, Dr. Raj Vuppalanchi reported at the annual Digestive Disease Week.
Among 231 participants in the PIVENS (Pioglitazone versus Vitamin E versus Placebo for the Treatment of Nondiabetic Patients with Nonalcoholic Steatohepatitis) trial, every 100-U/L decline in serum cytokeratin fragment (CK-18) level was significantly associated with overall histological improvement (P less than .001); resolution of NASH (P = .002); and improvement of at least 1 point in steatosis grade, hepatocellular ballooning, and nonalcoholic fatty liver disease (NAFLD) score (P less than .001 for all).
"We feel that serum CK-18 is a potentially useful surrogate marker for detection of improvement in clinical trials for NASH," said Dr. Vuppalanchi from Indiana University in Indianapolis.
Dr. Raj Vuppalanchi
Dr. Keith D. Lindor, executive vice provost for health at Arizona State University in Phoenix, said in an interview that CK-18 shows promise as a marker for disease activity in NASH but offers only limited information.
"It doesn’t hold the possibility of giving as much detailed information as a biopsy. We look at the amount of fat, amount of inflammation, amount of scarring – the biopsy lets us do that, but I don’t think a single serum assay will allow that," he said.
Dr. Lindor, who was not involved in the study, moderated the session at which the data were presented.
In previous cross-sectional studies, circulating CK-18 levels were shown to be associated with steatohepatitis in people with NAFLD, but it was unclear whether longitudinal changes in CK-18 would reflect changes in liver histology, Dr. Vuppalanchi said.
The investigators looked at CK-18 levels measured at baseline and at 16, 48, and 96 months among 231 of the 247 patients enrolled in the PIVENS trial, which compared vitamin E and/or pioglitazone against placebo in nondiabetic patients with NASH. The participants had liver biopsies at baseline and after 96 weeks of treatment.
The main trial results showed that vitamin E, but not pioglitazone, was significantly better than placebo at improvement of steatohepatitis.
Dr. Keith D. Lindor
In this substudy, the authors found that, compared with placebo, serum CK-18 levels were significantly lower in vitamin E–treated patients (P = .02 at 16 weeks, and P = .009 at 48 and 96 weeks). Among pioglitazone-treated patients, there was a similar pattern of lower CK-18 levels vs. placebo at all three time intervals (P = .001 for all).
Reductions in CK-18 correlated strongly with disease measures. For each 100-U/L decrease in CK-18 over 96 weeks, the odds ratios (ORs) were as follows: overall histological improvement (OR, 1.41; P less than .001); resolution of NASH (OR, 1.31; P = .002); and 1 point or more improvement in steatosis grade (OR, 1.45; P less than .001), hepatocellular ballooning (OR, 1.36; P less than .001), and NAFLD (OR, 1.41; P less than .001).
The study was supported by the National Institutes of Health with additional funding from Takeda Pharmaceuticals. Dr. Vuppalanchi and Dr. Lindor reported having no financial disclosures.