The within-individual reproducibility of the disease severity index from the HepQuant SHUNT test of liver function and physiology

Liver function and portal-systemic shunting quantified by the oral cholate challenge test and risk for large oesophageal varices

BACKGROUND

The quantitative HepQuant SHUNT test of liver function and physiology generates a disease severity index (DSI) that correlates with risk for clinical complications, such as large oesophageal varices (LEVs). A derivative test, HepQuant DuO, generates an equivalent DSI and simplifies testing by requiring only oral administration of the test solution and two blood samples at 20 and 60 min.

AIMS

Since the DSIs measured from DuO and SHUNT are equivalent, we compared the diagnostic performance for large oesophageal varices (LEVs) between the DSIs measured from DuO and SHUNT tests.

METHODS

This study combined the data from two prospectively conducted US studies: HALT-C and SHUNT-V. A total of 455 subjects underwent both the SHUNT test and esophagogastroduodenoscopy (EGD).

RESULTS

DSI scores correlated with the probability of LEVs (p < 0.001) and demonstrated a stepwise increase from healthy lean controls without liver disease to subjects with chronic liver disease and no, small or large varices. Furthermore, a cutoff of DSI ≤ 18.3 from DuO had a sensitivity of 0.98 (missing only one case) and, if applied to the endoscopy (EGD) decision, would have prevented 188 EGDs (41.3%). The AUROC for DSI from DuO did not differ from that of the reference SHUNT test method (0.82 versus 0.81, p = 0.3500).

CONCLUSIONS

DSI from HepQuant DuO links liver function and physiology to the risk of LEVs across a wide spectrum of patient characteristics, disease aetiologies and liver disease severity. DuO is minimally invasive, easy to administer, quantitative and may aid the decision to avoid or perform EGD for LEVs.

Hepatic Dysfunction Quantified by HepQuant DuO Outperforms Child-Pugh Classification in Predicting the Pharmacokinetics of Ampreloxetine

HepQuant tests quantify liver function from clearance of deuterium- and 13C-labeled cholates administered either intravenously and orally (SHUNT) or orally (DuO). Hepatic impairment studies have relied on clinical or laboratory criteria like Child-Pugh classification to categorize the degree of hepatic dysfunction. We compared HepQuant tests with Child-Pugh classification in predicting the pharmacokinetics of ampreloxetine. Twenty-one subjects with hepatic impairment (8 Child-Pugh A, 7 Child-Pugh B, and 6 Child-Pugh C), and 10 age- and sex-matched controls were studied. The pharmacokinetics of ampreloxetine were measured after oral administration of a single dose of 10 mg. Disease severity index (DSI), portal-systemic shunting (SHUNT%), hepatic reserve, and hepatic filtration rates (HFRs) were measured from serum samples obtained after intravenous administration of [24-13C]-cholate and oral administration of [2,2,4,4-2H]cholate. Ampreloxetine plasma exposure (AUC0-inf) was similar to controls in Child-Pugh A, increased 1.7-fold in subjects with Child-Pugh B, and 2.5-fold in subjects with Child-Pugh C and correlated with both Child-Pugh score and HepQuant parameters. The variability observed in ampreloxetine exposure (AUC0-inf) in subjects with moderate (Child-Pugh B) and severe hepatic impairment (Child-Pugh C) was explained by HepQuant parameters. Multivariable regression models demonstrated that DSI, SHUNT%, and Hepatic Reserve from SHUNT and DuO were superior predictors of ampreloxetine exposure (AUC0-inf) compared to Child-Pugh score. HepQuant DSI, SHUNT%, and hepatic reserve were more useful predictors of drug exposure than Child-Pugh class for ampreloxetine and thus may better optimize dose recommendations in patients with liver disease. The simple-to-administer, oral-only DuO version of the HepQuant test could enhance clinical utility.

Hepatic improvement within 27 days of avenciguat treatment in Child-Pugh A cirrhosis detected by an oral cholate challenge test

New methods for measuring hepatic improvement in clinical trials and the clinic are needed. One new method, HepQuant SHUNT, detected dose-dependent improvements in hepatic function and portal physiology in the phase 1b study (NCT03842761) of avenciguat, an activator of soluble guanylyl cyclase that is being developed for the treatment of portal hypertension. Herein, we examined whether HepQuant Duo, an easy-to-administer test version, could similarly detect the effects of avenciguat. Twenty-three patients with Child-Pugh A cirrhosis and liver stiffness >15 kPa received either a placebo (n = 5) or a maximum twice-daily avenciguat dose of 1, 2, or 3 mg (n = 6 per group) for 28 days. The DuO test was performed at baseline and on days 11 and 27 in each subject. The test involved administering 40 mg of d4-cholate orally, measuring d4-cholate concentrations in serum at 20 and 60 minutes, and calculating portal hepatic filtration rate, disease severity index, portal-systemic shunting (SHUNT%), and hepatic reserve (HR%). Avenciguat demonstrated dose-dependent improvement in all test parameters. Changes from baseline in SHUNT% after 27 days' treatment were 0.1 ± 9.0% for placebo, 1.7 ± 5.5% for 1 mg twice-daily, -3.2 ± 2.7% for 2 mg twice-daily, and -6.1 ± 5.0% for 3 mg twice-daily (paired t test for change from baseline p = 0.98, 0.48, 0.04, and 0.03, respectively). The changes detected by HepQuant DuO were similar to those previously observed and reported for HepQuant SHUNT. The results support further study of avenciguat in treating portal hypertension and spotlight the utility of HepQuant DuO in the development of drug therapy for liver disease. HepQuant DuO facilitates the use of function testing to measure hepatic improvement in clinical trials and the clinic.

Within-individual reproducibility of a dual sample oral cholate challenge test (DuO) and simplified versions of the HepQuant SHUNT test

Current noninvasive liver tests measure fibrosis, inflammation, or steatosis and do not measure function. The HepQuant platform of noninvasive tests uniquely assesses both liver function and physiology through the hepatic uptake of stable isotopes of cholate. However, the prototypical HepQuant SHUNT test (SHUNT V1.0) is cumbersome to administer, requiring intravenous and oral administration of cholate and six peripheral venous blood samples over 90 min. To alleviate the burden of test administration, we explored whether an oral only (DuO) version, and other simplified versions, of the test could provide reproducible measurements of liver function. DuO requires only oral dosing and two blood samples over 60 min. The simplified SHUNT test versions were SHUNT V1.1 (oral and IV dosing but four blood samples) and SHUNT V2.0 (oral and IV dosing but only two blood samples over 60 min). In this paper, we describe the reproducibility of DuO and the simplified SHUNT tests relative to that of SHUNT V1.0; equivalency is described in a separate paper. Data from two studies comprising 236 SHUNT tests in 94 subjects were analyzed retrospectively by each method. All simplified methods were highly reproducible across test parameters with intraclass correlation coefficients >0.93 for test parameters Disease Severity Index (DSI) and Hepatic Reserve. DuO and SHUNT V2.0 improved reproducibility in measuring portal-systemic shunting (SHUNT%). These simplified tests, particularly DuO and SHUNT V2.0, are easier to administer and less invasive, thus, having the potential to be more widely accepted by care providers administering the test and by patients receiving the test.

Advances in noninvasive measurement of liver function and physiology: The HepQuant DuO test

Current noninvasive liver tests are surrogates for fibrosis and lack ability to directly measure liver function. HepQuant tests measure liver function and physiology through hepatic uptake of stable cholate isotopes. HepQuant SHUNT (V1.0) involves oral and intravenous dosing and six blood samples over 90 min. We developed simplified test versions: SHUNT V2.0 (oral and intravenous dosing, two blood samples over 60 min) and DuO (oral dosing only, two blood samples over 60 min). The aim of this study was to evaluate equivalency of the simplified tests to the original SHUNT test. Data from three studies comprising 930 SHUNT tests were retrospectively analysed by each method. Equivalence was evaluated in terms of proportion of tests in which the difference between methods was less than any clinically meaningful difference and additionally by two one-sided t-test and bioequivalence methods. DuO and SHUNT V2.0 were equivalent to the original SHUNT test for Disease Severity Index, with >99% and >96% of tests falling within equivalence bounds. DuO and SHUNT V2.0 met equivalency criteria by two one-sided t-tests and bioequivalence. DuO and SHUNT V2.0 are easier to administer, are less invasive than the original SHUNT test and have potential to be more accepted by patients and providers.

Safety and pharmacokinetics of BI 685509, a soluble guanylyl cyclase activator, in patients with cirrhosis: A randomized Phase Ib study

BACKGROUND

Portal hypertension is a severe complication of cirrhosis. This Phase Ib study (NCT03842761) assessed the safety, tolerability, and pharmacokinetics of soluble guanylyl cyclase activator BI 685509 in patients with mild or moderate hepatic impairment (Child-Pugh [CP] A or B cirrhosis) and healthy volunteers (HVs).

METHODS

In this single-center, randomized, placebo-controlled study, patients received BI 685509 (maximum doses: 1, 2, or 3 mg, twice daily [BID]) or placebo for 28 days. HVs received one 0.5 mg dose of BI 685509 or placebo.

RESULTS

In total, 64 participants (CP-A, n=24; CP-B, n=25; HVs, n=15) were included; most commonly with NAFLD (36.7%), alcohol-associated (30.6%), or chronic viral hepatitis-related cirrhosis (28.6%). In patients with CP-A cirrhosis, drug-related adverse events (AEs) occurred in 5.6% of BI 685509-treated patients and 16.7% of placebo recipients. In patients with CP-B cirrhosis, drug-related AEs occurred in 26.3% of BI 685509-treated patients only. No serious AEs occurred in patients with CP-A cirrhosis; in patients with CP-B cirrhosis, serious AEs (not drug-related) occurred in 10.5% of BI 685509-treated patients and 16.7% of patients receiving placebo. BI 685509 was rapidly absorbed; exposure increased with dosage and was similar between etiologies and between patients with CP-A cirrhosis and patients with CP-A cirrhosis but lower in HVs. The mean percentage portal-systemic shunt fraction was measured in patients with CP-A cirrhosis and decreased at the end of treatment in the 2 mg BID (-11.2 ± 11.9%) and 3 mg BID (-14.0 ± 8.4%) BI 685509 dose groups, but not in the placebo group (+1.0 ± 27.3%).

CONCLUSION

BI 685509 was generally well tolerated, with 3 serious, not drug-related AEs reported in patients with CP-B cirrhosis. In patients with CP-A cirrhosis, portal-systemic shunt fraction in the exploratory efficacy analysis was reduced by 2 mg BID and 3 mg BID BI 685509.

Compartmental model describing the physiological basis for the HepQuant SHUNT test

The HepQuant SHUNT test quantifies hepatic functional impairment from the simultaneous clearance of cholate from the systemic and portal circulations for the purpose of monitoring treatment effects or for predicting risk for clinical outcome. Compartmental models are defined by distribution volumes and transfer rates between volumes to estimate parameters not defined by noncompartmental analyses. Previously, a noncompartmental analysis method, called the minimal model (MM), demonstrated reproducible and reliable measures of liver function (Translational Research 2021). The aim of this study was to compare the reproducibility and reliability of a new physiologically based compartmental model (CM) vs the MM. Data were analyzed from 16 control, 16 nonalcoholic steatohepatitis (NASH), and 16 hepatitis C virus (HCV) subjects, each with 3 replicate tests conducted on 3 separate days. The CM describes transfer of cholates between systemic, portal, and liver compartments with assumptions from measured or literature-derived values and unknown parameters estimated by nonlinear least-squares regression. The CM was compared to the MM for 6 key indices of hepatic disease in terms of intraclass correlation coefficient (ICC) with a lower acceptable limit of 0.7. The CM correlated well with the MM for disease severity index (DSI) with R² (95% confidence interval) of 0.96 (0.94-0.98, P < 0.001). Acceptable reproducibility (ICC > 0.7) was observed for 6/6 and 5/6 hepatic disease indices for CM and MM, respectively. SHUNT, a measure of the absolute bioavailability, had ICC of 0.73 (0.60-0.83, P = 0.3095) for MM and 0.84 (0.76-0.90, P = 0.0012) for CM. The CM, but not the MM, allowed determination of anatomic shunt and hepatic extraction and improved the within individual reproducibility.

HepQuant SHUNT Detects Portal Hypertension in Early Stages of Clinically Compensated Chronic Liver Disease

Physicians use portal pressure measurements in clinical practice and research but the methods are invasive, can cause complications, and are resource intensive.^1-3 Herein we describe preliminary findings of the minimally invasive HepQuant-SHUNT test in the diagnosis of portal hypertension in precirrhotic and compensated cirrhotic patients.

Value of Liver Function Tests in Cirrhosis

The liver comprises both parenchymal and non-parenchymal cells with varying functions. Cirrhosis is often complicated by the development of portal hypertension and its associated complications. Hence, assessment of liver in cirrhosis should include assessment of its structural, function of both hepatic and non-hepatic tissue and haemodynamic assessment of portal hypertension. There is no single test that can evaluate all functions of liver and assess prevalence and severity of portal hypertension. Commonly available tests like serum bilirubin, liver enzymes (alanine [ALT] and aspartate aminotransferase [AST], serum alkaline phosphatase [ALP], gamma glutamyl transpeptidase [GGT]), serum albumin and prothrombin time for assessment of liver functions partly assess liver functions. quantitative liver functions like indocyanine clearance tests [ICG-K], methacetin breath test [MBT] were developed to assess dynamic status of liver but has its own limitation and availability. Imaging based assessment of liver by transient elastography, MRI based 99 mTc-coupled asialoglycoprotein mebrofenin scan help the clinician to assess liver function, functional volume of liver left after surgery and portal hypertension [PH]. Hepatic venous pressure gradient still remains the gold standard for the assessment of portal hypertension but is invasive and not available in all centres. Combinations of blood parameters in form of various indices like fibrosis score of 4 [FIB-4], Lok index, scores like model for end stage liver disease (MELD) and Child-Turcotte Pugh score are commonly used for assessing liver function in clinical practice.