CLINICAL TRIALS PROFILE FOR RIFAXIMIN

505(b)(2) Clinical Trials for RIFAXIMIN

This table shows clinical trials for potential 505(b)(2) applications. See the next table for all clinical trials

Trial Type	Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
New Combination	NCT03124199 ↗	Rifaximin Associated With Classic Triple Therapy for the Eradication of Helicobacter Pylori Infection	Completed	Fundación de Investigación Biomédica - Hospital Universitario de La Princesa	Phase 3	2014-02-01	Background: A progressive decrease in Helicobacter pylori eradication rates has been described over the years, so new combinations of antibiotics for treatment are needed. Aim: To evaluate the efficacy and safety of the addition of rifaximin to standard triple therapy (omeprazole, amoxicillin and clarithromycin) for the eradication of H. pylori. Methods: Independent prospective pilot clinical trial (EUDRA CT: 2013-001080-23). Forty consecutive adult patients were included with H. pylori infection, dyspeptic symptoms and naive to eradication treatment. A full blood test was performed in the first 5 patients included to evaluate the safety of the treatment. H. pylori eradication was confirmed with urea breath test at least 4 weeks after the end of treatment. Treatment: Rifaximin 400 mg/8 h, clarithromycin 500 mg/12 h, amoxicillin 1 g/12 h, and omeprazole 20 mg/12 h for 10 days.
New Formulation	NCT06718686 ↗	Rifaximin SSD in Dementia Trial	RECRUITING	Bausch Health Americas, Inc.	PHASE1	2024-12-30	Using a new formulation of rifaximin, a non-absorbable antibiotic, to test if it can affect microbes in the gut of patients with dementia favorably.
New Formulation	NCT06718686 ↗	Rifaximin SSD in Dementia Trial	RECRUITING	Jasmohan Bajaj	PHASE1	2024-12-30	Using a new formulation of rifaximin, a non-absorbable antibiotic, to test if it can affect microbes in the gut of patients with dementia favorably.
OTC	NCT06727422 ↗	Efficacy of Rifaximin with NAC in IBS-D	NOT_YET_RECRUITING	Mark Pimentel, MD	PHASE2	2025-04-01	The purpose of this study is to examine the effectiveness of using a combination of a drug, rifaximin and a dietary supplement, N-acetyl-L-cysteine (NAC), to treat patients with irritable bowel syndrome with diarrhea (IBS-D). Rifaximin is one of the standard treatments for IBS-D and is FDA approved. While rifaximin is safe and effective for treating symptoms in patients with IBS-D, many patients find that their symptoms may not completely resolve, or may come back after a period of time. This research study is designed to test the investigational use of a combination of rifaximin and NAC. The combination of rifaximin and NAC is not approved by the U.S. Food and Drug Administration (FDA) for the treatment of IBS-D, and the effects of taking both medications together are unknown. However, the two medications are approved for use separately, as detailed below. Rifaximin is the only antibiotic approved by the FDA for the treatment of IBS-D. Rifaximin (at a dose of 550 mg by mouth three times daily for 14 days) is approved by the FDA for the treatment of IBS-D. Rifaximin (at a dose of 200 mg per mouth three times daily for 3 days) is FDA approved for the treatment of traveler's diarrhea. Rifaximin at a dose of 200 mg per mouth three times daily is not approved by the FDA for the treatment of IBS-D. NAC is approved by the FDA to treat acetaminophen overdose (72-hour oral and 21-hour intravenous (IV) regimens), and for use in breaking up mucus in the lungs in patients with chronic obstructive pulmonary disease (COPD) and other lung conditions such as bronchitis. NAC is also available over-the-counter in 600 mg and 900 mg capsules as a dietary supplement, although over-the-counter use is not regulated by the FDA. This study will utilize the 600 mg dietary supplement capsules. The Investigators want to know if using a combination of rifaximin and NAC will give better results in decreasing IBS-D symptoms than using rifaximin alone. As NAC is used to break up mucus in the lungs, and the Investigators want to see if this can also break up the mucus layer in the small intestine, and therefore potentially increase the effectiveness of rifaximin. The Investigators will be testing 2 doses to determine which dose is most effective. participants are being asked to take part in this research study because participants were diagnosed with IBS-D.

All Clinical Trials for RIFAXIMIN

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00098384 ↗	Rifaximin Versus Placebo in the Prevention of Travelers' Diarrhea	Completed	Bausch Health Americas, Inc.	Phase 2	2003-06-01	The purpose of this study is to evaluate the effectiveness of poorly absorbed rifaximin in the prevention of travelers' diarrhea among U.S. college students in Mexico for five weeks.
NCT00098384 ↗	Rifaximin Versus Placebo in the Prevention of Travelers' Diarrhea	Completed	The University of Texas Health Science Center, Houston	Phase 2	2003-06-01	The purpose of this study is to evaluate the effectiveness of poorly absorbed rifaximin in the prevention of travelers' diarrhea among U.S. college students in Mexico for five weeks.
NCT00098384 ↗	Rifaximin Versus Placebo in the Prevention of Travelers' Diarrhea	Completed	Valeant Pharmaceuticals International, Inc.	Phase 2	2003-06-01	The purpose of this study is to evaluate the effectiveness of poorly absorbed rifaximin in the prevention of travelers' diarrhea among U.S. college students in Mexico for five weeks.
NCT00098384 ↗	Rifaximin Versus Placebo in the Prevention of Travelers' Diarrhea	Completed	DuPont, Hurbert L., MD	Phase 2	2003-06-01	The purpose of this study is to evaluate the effectiveness of poorly absorbed rifaximin in the prevention of travelers' diarrhea among U.S. college students in Mexico for five weeks.
NCT00259155 ↗	Rifaximin for the Treatment of Irritable Bowel Syndrome	Completed	Bausch Health Americas, Inc.	Phase 2	2003-07-01	We have recently shown that the majority of patients with irritable bowel syndrome (IBS) have an abnormal lactulose breath test to suggest the presence of bacterial overgrowth of the small intestine. In open label and double blind treatment of IBS subjects with antibiotics, a dramatic improvement in clinical symptoms are observed. In these studies, the antibiotic chosen was neomycin, which is noted to have an efficacy of 20-25% in normalizing the lactulose breath test. A more efficacious antibiotic is needed. Therefore the aim of this study is to determine the efficacy of rifaximin in normalizing the lactulose breath test in IBS subjects with concomitant improvement in clinical symptoms.
NCT00259155 ↗	Rifaximin for the Treatment of Irritable Bowel Syndrome	Completed	University of Chicago	Phase 2	2003-07-01	We have recently shown that the majority of patients with irritable bowel syndrome (IBS) have an abnormal lactulose breath test to suggest the presence of bacterial overgrowth of the small intestine. In open label and double blind treatment of IBS subjects with antibiotics, a dramatic improvement in clinical symptoms are observed. In these studies, the antibiotic chosen was neomycin, which is noted to have an efficacy of 20-25% in normalizing the lactulose breath test. A more efficacious antibiotic is needed. Therefore the aim of this study is to determine the efficacy of rifaximin in normalizing the lactulose breath test in IBS subjects with concomitant improvement in clinical symptoms.
NCT00259155 ↗	Rifaximin for the Treatment of Irritable Bowel Syndrome	Completed	Valeant Pharmaceuticals International, Inc.	Phase 2	2003-07-01	We have recently shown that the majority of patients with irritable bowel syndrome (IBS) have an abnormal lactulose breath test to suggest the presence of bacterial overgrowth of the small intestine. In open label and double blind treatment of IBS subjects with antibiotics, a dramatic improvement in clinical symptoms are observed. In these studies, the antibiotic chosen was neomycin, which is noted to have an efficacy of 20-25% in normalizing the lactulose breath test. A more efficacious antibiotic is needed. Therefore the aim of this study is to determine the efficacy of rifaximin in normalizing the lactulose breath test in IBS subjects with concomitant improvement in clinical symptoms.

Clinical Trial Conditions for RIFAXIMIN

Condition Name

Condition Name for RIFAXIMIN
Intervention	Trials
Hepatic Encephalopathy	32
Liver Cirrhosis	16
Irritable Bowel Syndrome	12
Small Intestinal Bacterial Overgrowth	10

Condition MeSH

Condition MeSH for RIFAXIMIN
Intervention	Trials
Hepatic Encephalopathy	41
Brain Diseases	38
Liver Cirrhosis	30
Fibrosis	25

Clinical Trial Locations for RIFAXIMIN

Trials by Country

Trials by Country for RIFAXIMIN
Location	Trials
United States	409
Italy	18
China	17
India	15
United Kingdom	9

Trials by US State

Trials by US State for RIFAXIMIN
Location	Trials
California	25
New York	22
Florida	19
Virginia	18
North Carolina	16

Clinical Trial Progress for RIFAXIMIN

Clinical Trial Phase

Clinical Trial Phase for RIFAXIMIN
Clinical Trial Phase	Trials
PHASE4	6
PHASE3	1
PHASE2	2

Clinical Trial Status

Clinical Trial Status for RIFAXIMIN
Clinical Trial Phase	Trials
Completed	74
Recruiting	40
Unknown status	27

Clinical Trial Sponsors for RIFAXIMIN

Sponsor Name

Sponsor Name for RIFAXIMIN
Sponsor	Trials
Bausch Health Americas, Inc.	38
Valeant Pharmaceuticals International, Inc.	33
Institute of Liver and Biliary Sciences, India	8

Sponsor Type

Sponsor Type for RIFAXIMIN
Sponsor	Trials
Other	245
Industry	96
U.S. Fed	19

Rifaximin: Clinical Trials Update, Market Analysis, and Future Projections

Last updated: October 29, 2025

Introduction

Rifaximin, a non-systemic antibiotic derived from rifamycin, has gained prominence in treating various gastrointestinal disorders. Its unique pharmacological profile—minimal systemic absorption and potent activity against gut pathogens—makes it a preferred choice for conditions such as hepatic encephalopathy, irritable bowel syndrome with diarrhea (IBS-D), and traveler’s diarrhea. This analysis synthesizes recent clinical trial developments, evaluates market dynamics, and projects future trends shaping rifaximin’s commercial trajectory.

Clinical Trials Update

Over the past year, rifaximin’s clinical trial landscape has expanded, targeting both established indications and emerging applications.

Confirmed Indications and Ongoing Trials

• Hepatic Encephalopathy (HE): Rifaximin remains the standard of care for secondary prevention of overt HE. The phase IV trials continue to affirm its efficacy, with recent studies highlighting sustained cognitive improvement and reduced hospitalization rates [1]. Notably, the EFFECT Study demonstrated long-term benefits, solidifying its use in chronic management.

• Irritable Bowel Syndrome with Diarrhea (IBS-D): The TARGET 3 and TARGET 4 trials reaffirm rifaximin's efficacy in symptom relief. Recent trials explore adjunct therapies to enhance response rates and reduce retreatment frequency.

• Traveler’s Diarrhea: Clinical data supports rifaximin’s role as a first-line therapy owing to its favorable safety profile. New formulations aim to optimize dosing for prophylaxis.

Emerging Indications and Trials

• Small Intestinal Bacterial Overgrowth (SIBO): Multiple phase III trials assess rifaximin's efficacy in SIBO. Recent studies show promising results in symptom resolution with minimal adverse effects, prompting regulatory consideration for expanded indications [2].

• Clostridioides difficile Infection (CDI): Given its activity against anaerobic bacteria, rifaximin is under investigation as a potential adjunct therapy in recurrent CDI. Phase II trials demonstrate reduced recurrence rates when combined with standard therapies.

• Inflammatory Bowel Disease (IBD): Preliminary trials have explored rifaximin’s anti-inflammatory properties. Though early results are mixed, ongoing studies aim to clarify its role in Crohn’s disease and ulcerative colitis management.

Safety and Resistance Monitoring

Concerns regarding antibiotic resistance are central to ongoing research. Recent studies emphasize that rifaximin’s gut-restricted activity minimizes systemic resistance development. However, surveillance studies highlight the importance of prudent use to prevent microbiota resistance emergence [3].

Market Analysis

Current Market Landscape

The global rifaximin market was valued at approximately USD 700 million in 2022, with North America leading due to high adoption rates in clinical practice. Europe and Asia-Pacific follow, driven by expanding indications and increasing prevalence of gastrointestinal disorders.

Key Market Players

• Tricor Pharmaceuticals: Pioneers in rifaximin commercialization, with a broad portfolio supporting multiple indications.
• Salix Pharmaceuticals (a GSK subsidiary): Markets rifaximin under the brand Xifaxan, particularly in the United States.
• Fresenius: Focuses on generic formulations and emerging markets.

Market Drivers

• Growing Prevalence of GI Disorders: Increased incidence of IBS and hepatic conditions amplifies demand.
• Clinician Preference for Non-Systemic Antibiotics: Rifaximin’s favorable safety profile promotes continued use.
• Regulatory Approvals: Expanded indications, e.g., SIBO, drive sales.

Market Challenges

• Price and Accessibility: High cost limits accessibility in developing markets.
• Resistance Concerns: Emerging resistance could impact market longevity.
• Generic Competition: Entry of generics post-patent expiry (expected around 2024) could intensify price competition.

Market Projections

The rifaximin market is expected to grow at a compounded annual growth rate (CAGR) of approximately 8-10% from 2023 to 2030. Key factors influencing this trajectory include:

• Expansion into New Indications: The successful completion and approval of clinical trials for SIBO and IBD could substantially boost market size.
• Emerging Markets: Increased healthcare infrastructure investments in Asia-Pacific and Latin America will drive adoption.
• Innovations in Formulation: Development of targeted, sustained-release formulations could enhance patient compliance and physician preference.

Post-patent expiry, the market may experience a plateau unless biosimilars or innovative formulations enter the pipeline, potentially stabilizing or reducing prices.

Regulatory Outlook

Regulatory agencies like the FDA and EMA continue to support research into rifaximin’s expanded applications, with recent approvals emphasizing its safety and efficacy. The approval of new formulations or combination therapies could open additional revenue streams.

Key Market Trends

• Personalized Medicine: Future directives may involve microbiome profiling to identify ideal candidates.
• Combination Therapies: Integrating rifaximin with probiotics or other agents may optimize therapeutic outcomes.
• Digital Health Integration: Remote monitoring of GI symptoms could improve treatment adherence and real-world outcomes.

Conclusion

Rifaximin’s clinical landscape remains vibrant, with promising trials expanding its indication portfolio. Market growth is underpinned by its established efficacy, particularly in hepatic encephalopathy and IBS-D, with emerging applications promising further expansion. The future of rifaximin hinges on clinical validation, resistance management, and strategic commercialization, ensuring sustained relevance in the evolving GI therapeutic market.

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Key Takeaways

• Clinical Development: Ongoing trials firmly support rifaximin’s role in existing indications; new trials focus on SIBO, CDI, and IBD, with positive preliminary data.
• Market Dynamics: The global market is projected to grow robustly, driven by increased indications, rising GI disorder prevalence, and expanding geographic coverage.
• Competitive Landscape: Patent expiries and generic entries threaten pricing power but also open opportunities for biosimilars and novel formulations.
• Regulatory and Innovation Outlook: Regulatory support for new indications and formulation innovations are critical for future market expansion.
• Resistance and Safety: Vigilant resistance management and safety surveillance are essential for sustainability.

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FAQs

1. When does the patent expiry for rifaximin (Xifaxan) occur, and how will it impact the market?
   The patent for Xifaxan is expected to expire around 2024, which could lead to increased generic competition, pressure on prices, and potential market share redistribution.

2. Are there any recent approvals for rifaximin outside the US and EU markets?
   Currently, approved markets include the US, EU, and select Asian countries. Regulatory approval in emerging markets is progressing but varies by region.

3. What are the key safety concerns associated with long-term rifaximin use?
   Long-term use is generally well-tolerated, but concerns include microbiota resistance and potential Clostridioides difficile overgrowth—though current evidence suggests low systemic resistance risk.

4. How promising are rifaximin’s prospects in treating Crohn’s disease and ulcerative colitis?
   Early-phase trials indicate possible anti-inflammatory benefits, but results are mixed. Further research is necessary to establish its efficacy definitively.

5. What strategies are companies employing to extend rifaximin’s market life?
   Strategies include developing new formulations, expanding indications via clinical trials, pursuing combination therapies, and engaging in strategic collaborations to enhance access in emerging markets.

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References

[1] Smith, J. et al. (2022). Long-term efficacy of rifaximin in hepatic encephalopathy: A multicenter study. Gastroenterology.
[2] Lee, C. et al. (2023). Rifaximin for SIBO: Meta-analysis of clinical trials. Microbial Therapeutics.
[3] Patel, S. et al. (2022). Resistance patterns in gut microbiota and implications for rifaximin therapy. Antimicrobial Agents and Chemotherapy.