Phase III, multicenter, randomized, double-blind, placebo-controlled study of norursodeoxycholic acid in metabolic dysfunction-associated steatotic liver disease patients

Abstract

BACKGROUND

The norursodeoxycholic acid (norUDCA), a side chain-shortened derivative of ursodeoxycholic acid, exhibits unique pharmacological properties that may benefit patients with metabolic dysfunction-associated steatotic liver disease (MASLD).

AIM

To evaluate the efficacy, safety, and tolerability of norUDCA 1500 mg compared to placebo in the patients with MASLD.

METHODS

This phase III, randomized, double-blind, multi-centric, placebo-controlled trial enrolled patients with MASLD, and were randomized in 2:1 ratio to receive either norUDCA 1500 mg or placebo for 24 weeks. Efficacy and safety were rigorously evaluated through clinical, biochemical, and imaging assessments. Primary endpoints assessed alanine aminotransferase (ALT) normalization and improvement in liver stiffness (FibroScan^®) at week 12, while secondary endpoints included changes in nonalcoholic fatty liver disease fibrosis score, liver enzymes, lipid profile, glycosylated hemoglobin, and FibroScan-assessed liver stiffness. Safety was monitored throughout the study.

RESULTS

Of 165 randomized patients, 110 received norUDCA and 55 placebos. At week 12, ALT normalization was achieved in 89% of norUDCA-treated group compared to 76% of placebo-treated group (P = 0.022); with a statistically significant adjusted mean difference (P = 0.016). Fibrosis improvement was observed in 57% of norUDCA-treated vs 40% in placebo-treated (P = 0.035), with highly significant adjusted mean (P = 0.002). nonalcoholic fatty liver disease fibrosis score at week 18 and 24 (P = 0.041 and P = 0.032). Similarly, ALT reductions were significant at both week 18 and week 24 (P = 0.021 and P = 0.035). Improvements in lipid profile trended towards norUDCA without statistical significance. Liver stiffness has improved in 90 patients in norUDCA-treated vs 36 patients in placebo group (P = 0.009). NorUDCA demonstrated favorable safety profile, with no serious adverse events reported, and only mild to moderate adverse events were observed.

CONCLUSION

NorUDCA 1500 mg demonstrated clinically meaningful therapeutic efficacy in patients with MASLD, accompanied by consistently favorable safety profile.

Key Words: 24-norursodeoxycholic acid; Fatty liver; Liver diseases; Steatosis; Fibrosis; Metabolic dysfunction-associated steatotic liver disease; Nonalcoholic fatty liver disease

Core Tip: This phase III trial demonstrated that norursodeoxycholic acid (norUDCA) 1500 mg significantly improved liver function in metabolic dysfunction-associated steatotic liver disease patients, with a majority of patients achieving alanine aminotransferase normalization and showing fibrosis regression on FibroScan. Notably norUDCA demonstrated favorable safety profile with no serious adverse events reported. All adverse events reported were mild or moderate in intensity and recovered over time. These findings highlight the norUDCA’s efficacy and safety addressing the need for more approved promising therapies in managing metabolic dysfunction-associated steatotic liver disease.

INTRODUCTION

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly referred to as nonalcoholic fatty liver disease, is a spectrum of liver disorders characterized by the presence of hepatic steatosis in conjunction with one or more cardiometabolic risk factors, in the absence of significant alcohol consumption[1]. MASLD has emerged as leading cause of chronic liver disease worldwide and is now recognized as contributor to liver-related morbidity and mortality[2]. Current estimates indicate that MASLD affects approximately 30% of the adult population globally, with projections suggesting a rise to over 55% by 2040[3,4]. According to Indian National Association for Study of Liver, the prevalence of metabolic dysfunction-associated fatty liver disease in India is alarmingly high, with population-based studies reporting rates ranging from 9% to 53%, primarily driven by the rising burden of obesity, diabetes, and metabolic syndrome[5].

MASLD is strongly associated with obesity, insulin resistance, type 2 diabetes mellitus (T2DM), and dyslipidemia, reflecting its underlying metabolic etiology. The pathogenesis involves complex interactions including dysregulated lipid metabolism, chronic low-grade inflammation, oxidative stress, mitochondrial dysfunction, and alterations in gut microbiota[6]. The conditions often remain asymptomatic in the early stages, and is commonly detected through elevated liver enzymes, radiological evidence of steatosis, or histological assessment showing varying degrees of fibrosis[7-10]. In the absence of timely intervention, MASLD can progress to metabolic dysfunction-associated steatohepatitis, characterized by inflammation and hepatocyte injury, which may lead to progressive fibrosis, cirrhosis and hepatocellular carcinoma[11]. Furthermore, the European Association for Study of the Liver also reported that patients with MASLD, particularly those with advanced fibrosis are at an increased risk for extrahepatic complications including cardiovascular diseases, chronic kidney disease, type 2 diabetes and certain malignancies[12].

Despite the increasing prevalence and burden of MASLD, global pharmacological approvals remain limited. Currently, resmetirom (approved in United States), saroglitazar (approved in India), and more recently, semaglutide received accelerated Food and Drug Administration approval for the treatment of metabolic dysfunction-associated steatohepatitis in adults with moderate-to-advanced fibrosis. This new milestone highlights the evolving MASLD treatment landscape and emphasizes the continued unmet need for broadly accessible, targeted therapeutic interventions[13-16]. In the absence of widely approved pharmacotherapies, lifestyle modification remains the cornerstone of MASLD management. However, long-term success is often limited, particularly in individuals with obesity or metabolic comorbidities. Several pharmacological agents such as vitamin E, pioglitazone, glucagon-like peptide-1 receptor agonists, and sodium-glucose cotransporter-2 inhibitors have demonstrated varying degree of benefits, yet robust histological improvements remain elusive. Conversely, commonly used medications such as metformin, insulin, and statins have not demonstrated meaningful efficacy and are not recommended for MASLD management[16,17].

In light of these therapeutic limitations, there is an increasing interest in repurposing or developing novel agents with hepatoprotective properties. Ursodeoxycholic acid (UDCA), a naturally occurring bile acid, has been explored in MASLD due to its hepatoprotective, anti-inflammatory, immunomodulatory, antioxidant and anti-apoptotic properties. Although, UDCA has demonstrated biochemical improvements, particularly reductions in serum alanine aminotransferase (ALT) levels, randomized clinical trials have failed to show histological improvements in patients with non-alcoholic steatohepatitis (NASH)[18]. In contrast, 24-norursodeoxycholic acid (norUDCA), a synthetic side-chain-shortened C23 homologue of UDCA, exhibits enhanced pharmacological properties with relative resistance to side chain amidation, norUDCA undergoes cholehepatic shunting, leading to hepatic enrichment and prolonged activity in the liver[19,20]. These pharmacokinetic and pharmacodynamic characteristics indicate that norUDCA may offer histological and clinical benefits in MASLD/NASH beyond those achieved with UDCA.

Preclinical studies in animal models of NASH have shown that norUDCA reduces hepatic steatosis, inflammation, apoptosis, and fibrosis[21]. Preliminary clinical evidence also suggests that norUDCA improves liver enzymes and reduces steatosis in patients with MASLD, with a favorable safety profile even at higher doses[18,21-23]. Mechanistic studies indicate that norUDCA downregulates transforming growth factor β signaling and collagen type I expression, which are key mediators of fibrosis that promotes excessive extracellular matrix deposition, cell adhesion and migration processes, leading pathological tissue remodeling and scarring[24,25]. Through inhibition of these pathways, norUDCA exerts antifibrotic effects in the liver. In addition, norUDCA also modulates farnesoid X receptor (FXR) signaling not by direct FXR agonism, but by influencing FXR acetylation through attenuation of sirtuin 1 activity, a deacetylase that regulates FXR function[26]. Additionally, norUDCA regulates bile acid homeostasis and transporter expression and modulates other nuclear receptor pathways, including pregnane X receptor and constitutive androstane receptor, thereby acting as a pleiotropic regulator of hepatic metabolism and inflammation[26,27]. Collectively, these mechanisms provide a strong rationale for evaluating norUDCA as a therapeutic agent for MASLD/NASH. NorUDCA was also well tolerated at the dose of 1500 mg/day in healthy individuals, with a favorable pharmacokinetic profile supporting once-daily dosing[28].

Based on the favorable preclinical and early clinical findings of norUDCA, a randomized, double-blind, placebo-controlled phase III clinical trial was conducted to provide insights by evaluating a larger cohort of Indian patients, encompassing a broader range of disease stages, and assessing clinically relevant endpoints to determine the efficacy and safety of norUDCA at a total daily dose of 1500 mg in patients with MASLD.

MATERIALS AND METHODS

Study design and participation of study subjects

This prospective, randomized, double-blind, parallel-group, placebo-controlled, phase III study was conducted at 12 centers across India from October 2023 to July 2024. Inclusion criteria include patients willing to participate in the study, adhere to a stable diet, and abstain from alcohol throughout the study period. Male and female patients aged between 18 years to 65 years, with a body mass index (BMI) below 35 kg/m², diagnosed with MASLD by suggestive imaging findings by FibroScan, [A fibrosis score of F2-F3 (as per Metavir 5 scoring system), liver stiffness (> 7.5 kilopascals and < 14 kilopascals)] with abnormal ALT levels > 1.5 times and < 4 times the upper limit of normal and patients with child-bearing potential must agree to use medically acceptable forms of contraception during the study. Key exclusion criteria were patients with chronic liver disease, hepatic cirrhosis, portal hypertension, chronic renal disorders, or active viral infections. Patients with history of chronic use (≥ 12 months) of any drug known to be associated with MASLD development, prior or planned weight reduction surgery were excluded. Patients with uncontrolled diabetes [glycosylated hemoglobin (HbA1c) ≥ 9.5% or on insulin/glucagon-like peptide-1 receptor agonist/dipeptidyl peptidase-4 inhibitor therapy], uncontrolled thyroid disorders, recent cardiovascular events, uncontrolled hypertension, pregnancy, or breastfeeding were excluded. The study was approved by all relevant ethics committee, regulatory authorities at all centers, and has been registered at Clinical Trials Registry-India, registration identification number is CTRI/2023/08/055982.

Randomization and masking

Eligible patients were randomized in 2:1 ratio to receive norUDCA 1500 mg/day or matching placebo respectively. Randomization was conducted using a computer-generated block randomization schedule prepared by an independent statistician (using SAS version 9.4) and implemented via an Interactive Web Response System. Allocation codes were assigned sequentially upon enrollment and blinding was maintained for investigators, participants, and study staff.

Study procedure

The total duration of the study was approximately 29 weeks, including 7-day screening period, a 24-week treatment phase, and a 4-week post treatment safety follow-up after the completion of treatment. Eligible patients were randomized at baseline and received the investigational drug norUDCA or placebo. Patients were instructed to take three tablets of 500 mg (totaling 1500 mg) of either norUDCA or matching placebo once daily, with approximately 240 mL of drinking water after breakfast, at the same time each day. Study visits were scheduled at week 6, week 12 and week 18 (+ 2 days), during which the investigational product was dispensed. Patients recorded daily investigational product intake, adverse events (AEs), and concomitant medications in diary cards, which were reviewed and reissued at each visit. Drug accountability was documented in the electronic case report form. At week 28 (± 2 days), safety assessments including laboratory evaluations and a diary review were conducted.

Study endpoints

The primary endpoints were: (1) The proportion of patients achieving ALT normalization at week 12; and (2) The proportion of patients with improvement in liver stiffness (assessed by FibroScan) at week 12. Secondary endpoints included: (1) Change in nonalcoholic fatty liver disease fibrosis (NFS) score at week 6, 18, 24 from baseline; (2) Mean changes in serum ALT levels at week 6, 18, and 24 from baseline; (3) Aspartate aminotransferase (AST) levels at week 6, 12, 18, and 24 from baseline; (4) Mean change in lipid profile week 6, 12, 18, and 24; (5) Mean change in HbA1c at week 12, and 24 from baseline; and (6) The proportion of patients with comparative changes in liver stiffness (assessed by FibroScan) from baseline to week 24 and controlled attenuation parameter (CAP) score assessments. Safety endpoint included the incidence and severity of AEs and serious AEs (SAEs), as well as abnormal laboratory assessments from baseline to the end of the study.

Study assessment

Efficacy analyses were performed in both the intention-to-treat and per-protocol populations. The intention-to-treat population included all randomized patients who received at least one dose of study drug and had at least one post-baseline efficacy assessment, while the per-protocol population excluded patients with major protocol deviations. Missing data were handled using last observation carried forward. Liver stiffness was assessed noninvasively using FibroScan (transient elastography). Although liver biopsy remains gold standard for MASLD diagnosis and monitoring, its invasiveness limits its repeatability. FibroScan offers a validated, quantitative and reproducible alternative to assess liver fibrosis across the whole liver. FibroScan values for normal liver range from 2-6 kPa, with the device capable of measuring up to 75 kPa. Fibrosis staging was categorized as: F0-F1: No or mild fibrosis, F2: Moderate fibrosis, F3: Advanced fibrosis, and F4: Cirrhosis. Fibrosis improvement was defined as regression to a lower stage and no change in fibrosis stage (as per FibroScan) was considered as ‘no improvement’ in this study.

Statistical analysis

Sample size calculations were based on the primary composite endpoints (ALT normalization and liver stiffness improvement) The established literature values, assumed response rates in the placebo group were 15% for liver stiffness and 20% for ALT normalization[22]. The anticipated effect for FibroScan score were set at 0.01 and for ALT at 0.05, respectively[29]. Using a composite endpoint was the ‘odds ratio’ as the effect measure, zero correlation between endpoints, and assuming 5% type I error, and 20% type II error, the required sample size was estimated to be 132 patients. Assuming a 20% dropout rate, a total of 165 patients were enrolled (110 patients in norUDCA group, 55 in the placebo group).

Descriptive statistics were used to summarize continuous variables (mean ± SD) and nominal variables were presented as frequencies and percentages. Primary efficacy comparisons between groups were conducted using Pearson’s χ² test. The composite endpoints: Defined as ALT normalization and comparative changes in liver stiffness stage based on Fibro Scan score from baseline to week 12 were analyzed using matched-pairs approach and adjusted means 12 were estimated using analysis of covariance analysis of covariance. Liver steatosis was evaluated using the CAP score, measured with FibroScan probes and compared against liver biopsy results. Normal CAP values typically range from 100 dB/m to 400 dB/m. Secondary endpoints evaluated adjusted means for NFS score were assessed using analysis of covariance model. Between-group differences were tested for statistical significance. The mean changes in ALT, AST, lipid profiles, HbA1c, and FibroScan scores, controlling from baseline values. Mean changes from baseline to week 6, week 12, week 18 and week 24 were compared between two groups using independent samples t-test. The marginal homogeneity test was applied to compare fibrosis stage changes from baseline to week 24 between groups. The proportions of subjects with AE or SAE were compared using Pearson’s χ² test. AEs were classified and graded using CTCAE v5.0 and coded using MedDRA. Missing data were quantified, and the number of evaluable observations was reported. The study results were reported in accordance with the revised CONSORT 2025 statement[30].

RESULTS

Demographic and clinical characteristics of study subjects

A total of 165 patients meeting eligibility criteria were randomized in a 2:1 ratio to receive norUDCA 1500 mg daily (n = 110) or placebo (n = 55), respectively. Majority of enrolled participants were male (norUDCA group: 86.1% and placebo group: 81.8%) and of Asian descent. The mean age was 40.99 years in the norUDCA group and 42.09 years in the placebo group and the BMI values for the norUDCA group and placebo group are quite similar, with mean values of 25.46 kg/m² and 25.60 kg/m², respectively (Table 1). Two patients in the norUDCA group were lost to follow-up and eventually withdrew consent at week 24 (Figure 1).

Figure 1 Consort flow chart of subject deposition. MAFLD: Metabolic dysfunction-associated fatty liver disease; UDCA: Ursodeoxycholic acid.

Table 1 Baseline demographic data, n (%).

Variables	norUDCA group (n = 108)	Placebo group (n = 55)
Mean age (years)	40.99 (10.51)	42.09 (11.94)
Gender
Female	16 (13.9)	10 (18.2)
Male	94 (86.1)	45 (81.8)
BMI	25.46 (3.46)	25.60 (3.44)

norUDCA: Norursodeoxycholic acid; BMI: Body mass index.

Efficacy

The efficacy of the norUDCA was measured through normalization of ALT levels, and improvement in liver stiffness using FibroScan at week 12. A significantly higher proportion of patients in the norUDCA group achieved ALT normalization at week 12 compared to the placebo group (89.8% vs 76.4%; P = 0.022) (Figure 2, Table 2). The means of ALT levels (U/L) were adjusted with 95% confidence interval (CI) between two groups at various visits. At week 12, the ALT level was significantly lower in the norUDCA treated group (24.07 U/L; 95%CI: 21.01-27.13) than in the placebo group (30.59 U/L; 95%CI: 26.31-34.89; P = 0.016, Table 3).

Figure 2 Summary of patients achieving alanine aminotransferase normalization at week 12. ALT: Alanine aminotransferase; norUDCA: Norursodeoxycholic acid.

Table 2 Summary of patients achieved alanine aminotransferase normalization and improvements in the liver stiffness (using FibroScan) at week 12, n (%).

Visits	norUDCA group (n = 108)	Placebo group (n = 55)	P value
ALT normalization at week 12
Normalization	97 (89.8)	42 (76.4)	0.022
Abnormal	11 (10.2)	13 (23.6)
FibroScan stages at week 12
Improvement	62 (57.4)	22 (40.0)	0.035
No improvement	46 (42.6)	33 (34.5)

Normalization: Alanine aminotransferase ≤ 33 U/L for female and alanine aminotransferase ≤ 41 U/L for male; improvement: F2 to F0-F1; F3 to F0-F1; F3 to F2; No improvement: F2 to F2; F3 to F3. norUDCA: Norursodeoxycholic acid; ALT: Alanine aminotransferase.

Table 3 Summary of alanine aminotransferase in norursodeoxycholic acid and placebo groups at various visits, mean (95% confidence interval).

Visit	norUDCA	Placebo	P value
Visit 1/baseline	85.20 (81.34-89.06)	82.09 (77.37-86.82)	0.196
Visit 3/week 6	36.51 (28.88-44.24)	42.19 (31.49-52.89)	0.395
Visit 4/week 12	24.07 (21.01-27.13)	30.59 (26.31-34.89)	0.016
Visit 5/week 18	23.99 (20.54-27.46)	31.06 (26.21-35.92)	0.021
Visit 6/week 24	22.19 (18.13-26.25)	29.74 (24.04-35.44)	0.035

Mean of alanine aminotransferase are represented in U/L. norUDCA: Norursodeoxycholic acid.

The regression in liver stiffness at week 12 was observed in 62 (57.4%) patients in the norUDCA group, compared with 22 (40.0%) patients in the placebo group, with statistically significant difference between the groups (P = 0.035; Figure 3, Table 2). The means of FibroScan values were adjusted with 95%CI between two groups. At week 12, the norUDCA group showed FibroScan value of 7.46 kPa; 95%CI: 7.24-7.67, while placebo group showed 8.02 kPa; 95%CI: 7.73-8.32 with statistical significance (P = 0.002, Table 4). Secondary efficacy outcomes of norUDCA were further evaluated using NFS scores, improvements in liver enzymes, lipid profile parameters, HbA1c and improvements in liver stiffness.

Figure 3 Summary of patients showing improvements in fibrosis. A: At week 12; B: At week 24. norUDCA: Norursodeoxycholic acid.

Table 4 Summary of patients showing improvements in liver stiffness (using FibroScan) in norursodeoxycholic acid and placebo groups, mean (95% confidence interval).

Visits	norUDCA group (n = 108)	Placebo group (n = 55)	P value
Visit 4/week 12	7.46 (7.24-7.67)	8.02 (7.73-8.32)	0.002
Visit 6/week 24	6.46 (6.24-6.68)	7.12 (6.81-7.42)	0.001

norUDCA: Norursodeoxycholic acid.

NFS scores

The norUDCA group showed reduction in NFS score of -2.69 ± 1.34 from baseline to week 18, compared with -2.26 ± 1.55 in the placebo group, with this difference being statistically significant (P = 0.041). This trend continued in week 24, with NFS of -2.77 ± 1.31 for norUDCA and -2.26 ± 1.58 for placebo groups, respectively (P = 0.032, Figure 4).

Figure 4 Mean reductions from baseline to end of treatment in nonalcoholic fatty liver disease fibrosis scores. NFS: Nonalcoholic fatty liver disease fibrosis; norUDCA: Norursodeoxycholic acid.

Liver enzymes

The ALT levels declined in norUDCA treated group compared with placebo group at week 18 (23.99 U/L vs 31.06 U/L; P = 0.021) and at week 24 (22.19 U/L vs 29.74 U/L; P = 0.035; Table 3). Similarly, AST levels also declined during the course of the study in both groups; at baseline the AST level were 87.01 U/L in norUDCA and 92.29 U/L in placebo group, and by the week 24 the AST level decreased to 25.84 U/L in norUDCA and 32.36 U/L in placebo group. However, the reductions were statistically not significant (Table 5). Although other time points did not achieve statistical significance (P > 0.05), the trend towards lower AST levels in the treatment group supports a potential hepatoprotective benefit.

Table 5 Summary of aspartate aminotransferase levels in norursodeoxycholic acid and placebo groups at various visits, mean (95% confidence interval).

Visit	norUDCA	Placebo	P value
Visit 1/baseline	87.01 (76.80-97.22)	92.29 (78.68-105.90)	0.551
Visit 3/week 6	32.52 (25.46-39.58)	42.25 (32.35-52.15)	0.116
Visit 4/week 12	28.26 (23.91-32.61)	32.17 (26.08-38.27)	0.304
Visit 5/week 18	24.69 (21.28-28.12)	30.34 (25.55-35.13)	0.060
Visit 6/week 24	25.84 (20.42-31.26)	32.36 (24.76-39.96)	0.170

Mean of aspartate aminotransferase are represented in U/L. norUDCA: Norursodeoxycholic acid.

Lipid profile and HbA1c

A favorable trend with reductions in lipid parameters, including total cholesterol, high-density lipoprotein, low-density lipoprotein, and triglycerides was observed with norUDCA treatment, HbA1c levels remained relatively stable in both groups. However, these between-group differences were not statistically significant (Figure 5).

Figure 5 Mean reductions in lipid profile and glycosylated hemoglobin at baseline and end of the treatment. HbA1c: Glycosylated hemoglobin; norUDCA: Norursodeoxycholic acid; HDL: High-density lipoprotein; LDL: Low-density lipoprotein.

FibroScan assessment of fibrosis and steatosis

Treatment with norUDCA 1500 mg was associated with a statistically significant increase in positive treatment outcomes in the improvement of liver stiffness from baseline to week 24. Notably, at week 24, 90 (83.3%) patients in the norUDCA group demonstrated improvement vs 36 (65.5%) patients in the placebo group (P = 0.009) (Figure 3), confirming the antifibrotic benefit of the drug. Additionally, the CAP scores decreased in norUDCA group compared to placebo group at week 12 (243.40 dB/m vs 261.78 dB/m; P = 0.054), with a statistically significant mean change from baseline (P = 0.003) and at week 24 (228.0 dB/m vs 246.1 dB/m; P = 0.014; Table 6) establishing the anti-steatotic effect of norUDCA in MASLD.

Table 6 Summary of controlled attenuation parameter score in norursodeoxycholic acid and placebo groups at different time points.

Visit	norUDCA		Placebo		P value	Change from baseline (P value)
	n	mean ± SD	n	mean ± SD
Baseline	72	276.21 ± 47.56	38	271.74 ± 39.04	0.62
Visit 4/week 12	72	243.40 ± 45.14	38	261.78 ± 50.4	0.054	0.003
Visit 6/week 24	72	228.04 ± 45.69	38	246.10 ± 42.74	0.014	0.005

Means are represented in dB/m. norUDCA: Norursodeoxycholic acid.

Safety and tolerability

Treatment with norUDCA was well tolerated, with no SAEs reported. Of 110 patients, 42 (38.2%) in the norUDCA group and 14 (25.4%) in the placebo group experienced AEs mostly (96.4%) mild in severity. Of these, 42 (75.0%) AEs were assessed by investigators as unrelated to the study drug, 13 (23.2%) AEs were considered ‘unlikely’ related to study drug, while 1 (1.78%) AE was deemed ‘possibly related’ to study drug. Furthermore, 46 (27.9%) patients experienced at least one treatment-emergent AE, including 34 (30.9%) in the norUDCA group and 12 (21.8%) in the placebo group. The majority of AEs reported were gastrointestinal origin, including constipation, gastric irritation, epigastric pain, and abdominal discomfort (Table 7). Other reported AEs include dyslipidemia, and occurrence of new-onset of T2DM, which are likely attributed to intrinsic metabolic dysregulation associated with metabolic dysfunction-associated fatty liver disease, rather than a direct pharmacological effect of the study drug. Notably, the use of statins or insulin was prohibited to prevent confounding effect, which may have contributed to increased incidence of these AEs in both norUDCA and placebo groups.

Table 7 Summary of adverse events, n (%).

Adverse events	norUDCA 1500 mg (n = 108)	Placebo (n = 55)
Patients with at least one TEAE	34 (30.9)	12 (21.81)
Total number of adverse events	42 (38.2)	14 (25.4)
Adverse events
Abdominal bloating	1 (0.93)	0
Abdominal pain	1 (0.93)	0
Abrasion	1 (0.93)	0
Acidity	0	1 (0.02)
Body pain	1 (0.93)	0
Cold	1 (0.93)	0
Constipation	3 (2.78)	0
Cough	1 (0.93)	0
Diabetes (hyperglycaemia)	3 (2.78)	1 (0.02)
Dyslipidaemia	15 (13.89)	3 (5.5)
Elevated liver enzymes	1 (0.93)	0
Epigastric pain	1 (0.93)	0
Fever	2 (1.85)	1 (0.02)
Gastric irritation	2 (1.85)	0
Headache	2 (1.85)	1 (0.02)
Hyperglycemia (impaired fasting glucose)	0	1 (0.02)
Loose stool	0	1 (0.02)
Mild thrombocytopenia	0	1 (0.02)
Nausea	0	1 (0.02)
Raised bilirubin	1 (0.93)	0
Rhinitis	1 (0.93)	0
Thrombocytopenia	1 (0.93)	0
Type 2 diabetes mellitus	4 (3.70)	3 (0.05)

norUDCA: Norursodeoxycholic acid; TEAE: Treatment-emergent adverse events.

DISCUSSION

This phase III randomized placebo-controlled study provides robust evidence supporting the efficacy and safety of norUDCA 1500 mg/day in treatment of patients with MASLD. Over the 24-week treatment period, norUDCA resulted in significant improvements in key hepatic parameters, including ALT normalization and regression of liver stiffness and steatosis. These therapeutic benefits were evident within 12 weeks of treatment initiation and continued throughout the 24-week treatment period, indicating a rapid treatment effect.

This study achieved primary endpoint, as evidenced with a significantly higher proportion of patients in the norUDCA group achieving ALT normalization by week 12 compared with placebo. Maximal ALT normalization occurred at week 12 in the norUDCA group, after which relatively few patients required further normalization between weeks 12 and 24. This pattern suggests an early pharmacodynamic effect of norUDCA on hepatocellular injury and inflammation. This biochemical improvement was accompanied by a reduction in liver stiffness, consistent with clinically meaningful anti-inflammatory and antifibrotic properties of norUDCA. In contrast, the ALT improvements in the placebo group beyond week 12 can be attributed to lifestyle and behavioral changes (dietary modification, exercise, adherence to medical advice), which are frequently observed in MASLD clinical trials and may account for the reduced between-group difference at later time points. These findings are consistent with prior preclinical and phase I studies, which has established the therapeutic efficacy, and favorable safety of norUDCA in healthy volunteers[22,28]. Furthermore, the observed antifibrotic activity of norUDCA treatment demonstrates potential to reverse or halt fibrosis progression in MASLD. This multimodal action likely supports the observed improvements in liver stiffness and FibroScan staging in the patient cohort. These findings are in line with those reported by Traussnigg et al[23], whose phase II dose-finding study in patients with MASLD demonstrated a dose-dependent therapeutic effect, with biochemical and FibroScan based assessment of liver stiffness showing superior efficacy and safety at 1500 mg dose. The role of FibroScan in evaluating liver stiffness is well established, supported by comprehensive studies, and acknowledged by the United States Food and Drug Administration[31,32]. Similarly, in the present study, norUDCA treatment was associated with sustained structural improvements on FibroScan throughout the study period, while ALT normalization peaked at week 12, with few additional patients achieving normalization thereafter. This divergence likely reflects the distinct properties of the biomarkers: ALT reflects short-term hepatocellular injury, whereas FibroScan captures longer-term structural changes related to fibrosis and steatosis. Collectively, these findings reinforce the clinical relevance of norUDCA 1500 mg in achieving both biochemical and structural hepatic improvements.

A noteworthy observation in the present study was the measurable reductions in NFS scores, ALT levels and improvements in liver stiffness across all time points in norUDCA group, suggesting a treatment-specific effect rather than a placebo-driven improvement. However, a notable reduction in AST levels was observed in placebo group. This phenomenon was reported in other MASLD or NASH trials[33,34] and is often attributed to behavioural and physiological factors, including improved adherence to lifestyle recommendations, modest weight loss, and heightened patient engagement, collectively referred to as Hawthorne effect[35,36]. The absence of run-in period to stabilize such lifestyle-related improvements may have amplified the placebo effect in the current study. These observations highlight the need to carefully consider the placebo response in MASLD trial design, particularly with respect to endpoint selection, sample size calculation, and interpretation of efficacy outcomes[35]. Importantly, the efficacy observed in the placebo group over the study duration highlights the multifactorial nature of MASLD and the potential for a modest placebo response. Several mechanisms may underlie this effect including adherence to medical advice, healthier dietary habits, increased physical activity, reduced alcohol intake, and greater engagement with healthcare providers and lifestyle modifications which are known to improve hepatic biomarkers in MASLD, even in the absence of active pharmacologic therapy[37,38].

In this study, treatment with norUDCA was associated with modest reductions in total cholesterol, low-density lipoprotein, very-low-density lipoprotein, and triglyceride levels with relatively stable body weight, low-density lipoprotein and HbA1c levels. However, these differences were not statistically significant, suggesting the requirement of longer treatment durations to demonstrate statistical significance with norUDCA. Importantly, a substantial proportion of patients in norUDCA group demonstrated significant improvements in liver stiffness, confirming the antifibrotic benefit of the norUDCA. This aligns with the observations from preclinical and early-phase clinical studies that highlight its potential in ameliorating hepatic steatosis[22,28]. This study demonstrated a favorable safety and tolerability profile of norUDCA over 24-week treatment period, which is consistent with previous studies[23]. No SAEs were reported during the study duration, and no discontinuations occurred due to treatment-related AEs. The reported AEs were mild to moderate in severity and resolved without sequelae. The overall incidence of treatment-emergent AEs was similar between the norUDCA and placebo groups, suggesting a well-tolerated safety profile. These findings are consistent with the favorable safety profile of norUDCA reported in both early-phase clinical studies. In a phase I trial conducted by Panuganti et al[28], norUDCA was well tolerated with no dose-limiting toxicities, supporting its use at higher doses. Furthermore, in a phase II dose-finding study by Traussnigg et al[23], in patients with MASLD, norUDCA demonstrated a dose-dependent therapeutic effect with a favorable safety profile. Collectively, these data support the safety and tolerability of norUDCA in both healthy volunteers and patient populations.

Notably, the most frequently reported gastrointestinal AEs such as abdominal pain, bloating and constipation are in agreement with observations by Huang et al[39]. The incidence of these AEs did not differ significantly from placebo, further supporting the gastrointestinal tolerability of the drug[39]. A limited number of patients in norUDCA group experienced metabolic AEs, including dyslipidemia or new-onset T2DM, and hyperglycemia. Such findings align with observations from earlier dose-finding trials, where metabolic disturbances were either minimal or attributable to pre-existing comorbidities[23,28].

Overall, the findings of this trail offer substantial evidence to support the therapeutic potential of norUDCA in MASLD, particularly in addressing hepatic inflammation and fibrosis, which are the two key factors for disease progression. The early onset of efficacy, favorable safety profile and sustained improvements observed make norUDCA a viable first line treatment option for managing early stages of MASLD.

Limitation

A limitation of this study was the lack of a run-in period to control the lifestyle-related effects, which may have led to an overestimation of placebo responses and a relative underestimation of the treatment effect. Another limitation in this study was no independent data monitoring committee was established, but data quality was ensured through internal monitoring by the contract research organization’s and sponsor’s clinical quality assurance team and medical monitors, in line with good clinical practice standards. In addition, statistical analyses were performed by independent biostatisticians to provide external validation of the results. Another limitation of this study is the relatively short treatment duration of 24 weeks. MASLD is a chronic, slowly progressive disease, and longer study durations (≥ 48-72 weeks) are typically required to demonstrate durable antifibrotic efficacy and sustained safety outcomes. Additionally, liver biopsy, the gold standard for histological assessment, was not used due to its invasive nature; instead, FibroScan, a validated noninvasive alternative was employed. Transient elastography does not provide the same level of histopathological detail for spotting very early or mild liver damage. However, the Food and Drug Administration has recognized its clinical utility, supported by approximately 100 published clinical studies demonstrating strong concordance with biopsy findings justifies its use in the current study.

CONCLUSION

This phase III trial demonstrated that norUDCA at a dose of 1500 mg resulted in significant improvement in liver function, with a higher proportion of patients achieving ALT normalization, along with evidence of fibrosis regression as evidenced by FibroScan. These findings reinforce the therapeutic potential of norUDCA in patients with MASLD, offering a favorable balance of efficacy and safety. Given the current paucity of approved pharmacological therapies for MASLD, norUDCA may represent a viable treatment option for routine clinical use. Furthermore, a phase IV study may be warranted to evaluate effectiveness and AEs in broader populations.

ACKNOWLEDGEMENTS

We thank Ardent Clinical Research Service for successful execution and completion of the phase III clinical study.