Routine clinical and laboratory markers predicted histologic response to obeticholic acid therapy among patients with nonalcoholic steatohepatitis (NASH), investigators reported in Gastroenterology.
In a secondary analysis of data from the FLINT trial, histologic response at treatment week 24 correlated significantly with baseline nonalcoholic fatty liver disease activity score (NAS) greater than 5, baseline triglycerides 154 mg/dL or less, baseline international normalized ratio no greater than 1, baseline aspartate aminotransferase (AST) level no greater than 49 U/L, and at least a 17-U/L decrease from baseline in alanine aminotransferase (ALT) level.
A stepwise logistic regression model including these variables and receipt of obeticholic acid distinguished histologic responders from nonresponders with an area under the receiver operating characteristic curve (AUROC) of 0.83 (95% confidence interval, 0.77-0.89; P less than .0001). These parameters “are readily available clinical and biochemical characteristics that are routinely available to clinicians and may be applied to daily practice,” wrote Rohit Loomba, MD, of the University of California, San Diego, with his associates. They may show “that the patients most likely to achieve histologic response are those with higher disease activity, but still with largely conserved liver function, allowing for potential healing or improvement.”
NASH is expected to become the leading reason for liver transplantation in the next few decades. Several treatments can induce histologic hepatic improvement, but none are approved for NASH. Obeticholic acid (Ocaliva) is a selective agonist of the farsenoid X receptor ligand and is indicated for treating primary biliary cholangitis (PBC) in combination with ursodeoxycholic acid (UDCA).
In the 72-week, multicenter, randomized, double-blind FLINT trial, noncirrhotic adults with biopsy-confirmed NASH received once-daily obeticholic acid (25 mg) or placebo. Blinded pathologists interpreted biopsies. The primary endpoint (improvement in liver histology) was met in the interim analysis, so the researchers stopped collecting final liver biopsies.
The secondary analysis included all patients with baseline and final biopsies, including 73 histologic responders and 127 nonresponders. “[The] trends for each of the selected predictors was the same when comparing histologic responders to nonresponders, regardless of treatment group (obeticholic acid versus placebo),” the researchers wrote. The predictors are biologically feasible, the researchers contended – for example, high baseline NAS would be more susceptible to significant improvement, while lower baseline triglyceride levels might reflect a liver that “is less burdened by triglyceride secretion” and, therefore, might have greater capacity to heal. Both AST and ALT “are metrics of liver injury,” and lower baseline AST, in combination with greater reduction in ALT at week 24, probably reflected “AST and ALT levels that are closer to normal,” they added.
Nonetheless, the researchers acknowledged several possible sources of bias. Trial participants were recruited from tertiary care settings and had complete biopsy data, which might not reflect the overall NASH population. Overfitting also could have biased the model because the number of variables assessed approached the number of events being predicted. Furthermore, the model assessed no treatment other than obeticholic acid. “A more robust model could potentially be developed if multiple pharmacological interventions could be considered simultaneously,” the researchers noted. The ongoing phase 3 REGENERATE trial aims to confirm the benefit of obeticholic acid in patients with NASH, they added. Topline results are expected in October 2022.
The FLINT trial was funded by Intercept Pharmaceuticals and the National Institute of Diabetes and Digestive and Kidney Diseases. Dr. Loomba cochaired the FLINT trial protocol writing committee, is on the steering committee of the ongoing REGENERATE trial, and has received research funding from Intercept Pharmaceuticals, which developed and markets obeticholic acid. Several other coinvestigators reported ties to Intercept and to other pharmaceutical companies.
SOURCE: Loomba R et al. Gastroenterology. 2018 Sep 14. doi: 10.1053/j.gastro.2018.09.021.