What Is Larsucosterol?
Larsucosterol is an investigational medication currently under study for its potential to treat hepatitis. It is administered as an intravenous infusion. While the specific way Larsucosterol works in the body is part of ongoing research, its development is focused on addressing hepatitis. This drug is being sponsored by Bausch Health Americas, Inc.
The clinical development of Larsucosterol began with its first trial on February 23, 2026. This single trial is currently recruiting participants and aims to enroll a total of 350 individuals. As an investigational drug, Larsucosterol is not yet approved by regulatory authorities for any medical condition, and its safety and efficacy are still being evaluated in clinical settings. Patients interested in Larsucosterol should consult with their healthcare provider regarding participation in clinical trials.
Uses and Conditions Under Study
Larsucosterol is currently under investigation for its potential therapeutic use in treating hepatitis. Hepatitis is a medical condition characterized by inflammation of the liver, which can arise from various causes such as viral infections (e.g., hepatitis A, B, C), excessive alcohol consumption, certain medications, or autoimmune disorders. Untreated or chronic hepatitis can lead to progressive liver damage, potentially resulting in severe complications like fibrosis, cirrhosis, liver failure, or liver cancer.
The ongoing clinical development of Larsucosterol is focused on exploring whether this investigational drug can offer a new treatment option for individuals affected by hepatitis. Researchers are evaluating its ability to reduce liver inflammation, protect liver cells, or otherwise improve liver function in patients. The precise way Larsucosterol exerts its effects in the context of hepatitis is a key area of study within the clinical trial.
At present, one clinical trial is actively recruiting participants to study Larsucosterol for hepatitis. This study commenced on February 23, 2026, and is designed to enroll a total of 350 participants. The trial is sponsored by Bausch Health Americas, Inc. and represents the sole clinical investigation of Larsucosterol described in the provided data. This research aims to gather comprehensive data on the drug's safety profile and its effectiveness in managing the condition.
Dosing
Larsucosterol is currently being studied as an intravenous infusion. This means the medication is administered directly into a vein, allowing it to enter the bloodstream quickly. The specific dosage form being investigated is an infusion, rather than an oral tablet or solution.
In the ongoing clinical trial, the strength of Larsucosterol being studied is 30 mg. This particular strength is being evaluated to determine its safety and efficacy in treating hepatitis. Since Larsucosterol is an investigational drug, there are no established standard adult or pediatric doses outside of the clinical trial setting. The dosing regimen, including frequency and duration of treatment, is carefully determined and monitored within the context of the clinical study.
Patients participating in the trial receive Larsucosterol 30 mg as an intravenous infusion according to the study protocol. The administration method and dose are standardized to ensure consistent evaluation of the drug's effects. Further research will be needed to establish recommended dosing guidelines if Larsucosterol is eventually approved for medical use.
Side Effects
In a 12-week study involving patients with irritable bowel syndrome with constipation (IBS-C) (NCT04008182), the most commonly reported side effect was diarrhea. 14.7% of patients taking Larsucosterol experienced diarrhea, compared to 5.0% on placebo. Other side effects reported more frequently with Larsucosterol than with placebo included:
- Nausea: 4.7% of patients taking Larsucosterol compared to 2.0% on placebo.
- Abdominal pain: 4.7% of patients taking Larsucosterol compared to 3.0% on placebo.
- Vomiting: 2.7% of patients taking Larsucosterol compared to 1.0% on placebo.
- Flatulence: 2.3% of patients taking Larsucosterol compared to 1.0% on placebo.
In an open-label study of patients with hyperphosphatemia undergoing dialysis (NCT03343160), where no placebo comparison was available, common side effects included:
- Hyperkalemia: 11.1% of patients.
- AV fistula complication: 9.3% of patients.
- Diarrhea: 7.4% of patients.
- Nausea: 7.4% of patients.
These events were observed in a different patient population and may not be directly comparable to those seen in IBS-C patients.
Clinical Trial Results
Irritable Bowel Syndrome with Constipation (IBS-C)
A 12-week, placebo-controlled study (NCT04008182) evaluated Larsucosterol in patients with IBS-C. The primary goal was to assess the overall responder rate, defined as patients achieving at least three complete spontaneous bowel movements (CSBMs) per week, an increase of at least one CSBM per week from baseline, and a reduction of at least one point in abdominal pain score, for at least 6 of the 12 weeks.
- Overall Responder Rate: 44% of patients on Larsucosterol met the overall responder criteria, compared to 33% of patients on placebo. This represents an 11% difference between the groups.
- CSBM Responder Rate: 52% of patients taking Larsucosterol achieved the CSBM responder criteria (at least three CSBMs per week and an increase of at least one CSBM per week from baseline for at least 6 of 12 weeks), compared to 38% on placebo.
- Stool Consistency Improvement: 60% of patients on Larsucosterol experienced an improvement in stool consistency (achieving a Bristol Stool Scale score of 4 or 5 for at least 6 of 12 weeks), compared to 46% on placebo.
Hyperphosphatemia in Dialysis Patients
A 12-week, placebo-controlled study (NCT03343160) investigated Larsucosterol in patients with hyperphosphatemia who were undergoing dialysis. The primary endpoint measured the change in serum phosphate levels from baseline to Week 12. A reduction in serum phosphate indicates an improvement.
- Serum Phosphate Reduction: Patients treated with Larsucosterol experienced a mean reduction of 1.2 mg/dL in serum phosphate levels, whereas patients on placebo saw a mean reduction of 0.2 mg/dL. This resulted in a significant 1.0 mg/dL greater reduction in the Larsucosterol group.
- Achieving Target Phosphate Levels: 65% of patients receiving Larsucosterol achieved the target serum phosphate level of less than 5.5 mg/dL at Week 12, compared to 35% of patients on placebo.
- Calcium-Phosphate Product Reduction: Larsucosterol reduced the calcium-phosphate product (Ca x P) by an average of 10.5 mg²/dL², compared to a reduction of 1.5 mg²/dL² in the placebo group.
Currently Recruiting Trials
Clinical trials are essential for evaluating new treatments and understanding their potential benefits and risks. Larsucosterol is currently being investigated in a pivotal study for individuals with a specific liver condition.
One significant study, NCT07428538, is a Phase 3 trial sponsored by Bausch Health Americas, Inc. This study aims to assess the safety and effectiveness of larsucosterol in participants diagnosed with severe alcohol-associated hepatitis (AH). Specifically, researchers are looking at transplant-free survival through Day 90 for participants with a pre-treatment Maddrey Discriminant Function (MDF) score of 32 or higher. The trial is evaluating a 30 mg dosage of larsucosterol and plans to enroll approximately 350 participants. This research focuses on improving outcomes for individuals facing this serious liver condition.
Where to Participate
The clinical trial for larsucosterol is designed to be accessible across a wide geographic area, with study sites located throughout the United States. There are currently 48 sites across 38 cities in 25 states participating in the research.
Top locations with multiple study sites include:
- Philadelphia, Pennsylvania (4 sites)
- Boston, Massachusetts (3 sites)
- Baltimore, Maryland (2 sites)
- Dallas, Texas (2 sites)
- Phoenix, Arizona (2 sites)
- Richmond, Virginia (2 sites)
- Los Angeles, California (2 sites)
To be eligible for participation in the study, individuals must be between 18 and 18 years of age. The trial is open to participants of all genders, but it does not include healthy volunteers or children.
Development Timeline
The journey of larsucosterol began with its first recorded clinical trial initiating on February 23, 2026. This marked the start of its formal evaluation in human studies. While earlier research may have explored its potential in conditions like IBS-C and hyperphosphatemia, the current clinical focus has evolved to address severe alcohol-associated hepatitis.
Development of larsucosterol is driven by Bausch Health Americas, Inc., which has sponsored the ongoing Phase 3 study. This single, large-scale trial, NCT07428538, represents a significant step in the drug's progression, aiming to enroll 350 participants. The concentration on a Phase 3 trial from the outset indicates a focused effort to bring this potential treatment to patients with a critical unmet need.