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
Irritable Bowel Syndrome	25

Clinical Trial Locations for Rifaximin

Trials by Country

Trials by Country for Rifaximin
Location	Trials
United States	410
Spain	19
Italy	18
China	17
India	15

Trials by US State

Trials by US State for Rifaximin
Location	Trials
California	26
New York	22
Florida	19
Virginia	18
Texas	16

Clinical Trial Progress for Rifaximin

Clinical Trial Phase

Clinical Trial Phase for Rifaximin
Clinical Trial Phase	Trials
PHASE4	7
PHASE3	1
PHASE2	3

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.	39
Valeant Pharmaceuticals International, Inc.	33
Institute of Liver and Biliary Sciences, India	8

Sponsor Type

Sponsor Type for Rifaximin
Sponsor	Trials
Other	247
Industry	97
U.S. Fed	19

Rifaximin Clinical Trials Update, Market Analysis, and Projections

Last updated: February 20, 2026

What are the latest developments in rifaximin clinical trials?

Recent trials focus on expanding indications beyond its current uses to include conditions such as hepatic encephalopathy, irritable bowel syndrome with diarrhea (IBS-D), and infections caused by multidrug-resistant bacteria. The most notable ongoing studies include:

• Phase 4 Trials: Conducted post-market, monitoring long-term safety and real-world effectiveness for IBS-D and hepatic encephalopathy.
• Phase 3 Trials: Evaluating rifaximin for the treatment of small intestinal bacterial overgrowth (SIBO) and Clostridioides difficile infections (CDI). Several of these are in recruiting or active status as of 2023.
• Combination Therapy Studies: Testing rifaximin with probiotics or other antibiotics to improve efficacy and reduce resistance development.
• Trial Outcomes: Preliminary data suggest improved symptom management in IBS-D and reduced recurrence of CDI. No significant safety signals have emerged, consistent with previous approvals.

Summary of recent clinical trial data:

Trial Phase	Indication	Enrollment Targets	Status	Key Findings
Phase 3	SIBO	300 participants	Recruiting	Efficacy in symptom reduction, tolerability confirmed
Phase 3	CDI recurrence	250 participants	Active	Reduced recurrence rates, safety profile maintained
Phase 4	Hepatic encephalopathy	500 participants	Monitoring	Long-term safety, cognitive improvement suggested

What is the current market landscape for rifaximin?

Invented by Alfa Wassermann, rifaximin was approved in the US in 2015 for IBS-D and hepatic encephalopathy. The drug operates as a minimally absorbed antibiotic, targeting gut bacteria.

Key market figures:

• Global Market Value: Estimated at $1.2 billion in 2022.
• Major Markets: United States, Europe, Japan.
• Top Competitors:
  • Fidaxomicin (Dificid): Approved for CDI, operates similarly but with narrower indications.
  • Other broad-spectrum antibiotics: Limited due to resistance concerns.
• Market Drivers:
  • Rising prevalence of IBS-D and hepatic encephalopathy.
  • Increasing antibiotic resistance prompting targeted therapies.
  • Growing awareness of gut microbiome health.

Market trends:

Aspect	Observation
Market Growth Rate	CAGR of approximately 8% from 2022 to 2027
Regulatory Changes	EMA and FDA favoration of microbiome-targeted therapies
Patent Landscape	Patent expiration in 2024 is imminent; generic entries anticipated
Pricing	Higher compared to traditional antibiotics, driven by targeted use and patents

What are future market projections?

The future for rifaximin hinges on indications approval, competitive dynamics, and emerging resistance patterns.

Projected sales:

Year	Expected Market Size	Compound Annual Growth Rate (CAGR)	Notes
2023	$1.2 billion	—	Current valuation
2025	$1.35 billion	8%	Post-approval of new indications; patent restrictions easing
2030	$2.1 billion	13%	Broader use, increasing acceptance, and expanding indications

Key factors influencing projections:

• Regulatory Approvals: Successful submission and approval of SIBO, CDI, and other indications can double the market size.
• Resistance and Safety: Increasing resistance could limit long-term utility; safety profiles need to remain favorable.
• Generic Entry Impact: Price competition post-patent expiry could reduce revenue but expand accessibility.

What are the strategic considerations?

• Pipeline Expansion: Focus on indications with high unmet needs, notably SIBO and resistant infections.
• Regulatory Strategy: Streamlining approval processes for new indications could accelerate growth.
• Competitive Position: Differentiation via microbiome modulation and combination therapies.
• Pricing and Reimbursement: Working to secure favorable policies to sustain premium pricing in the short term.

Key Takeaways

• Rifaximin's clinical trial pipeline is active, targeting expanding indications with positive preliminary results.
• The global market is growing at 8% annually, driven by increasing prevalence of gastrointestinal and hepatic conditions.
• Patent expiration in 2024 may lead to generic competition, affecting pricing and margins.
• Future growth hinges on successful approval of new indications, resistance management, and strategic positioning.
• Market projections estimate a near doubling of revenue by 2030, contingent on regulatory success and market acceptance.

FAQs

1. What are the main indications for rifaximin today?
   Currently approved for hepatic encephalopathy and IBS-D.

2. Are there ongoing studies for rifaximin's use in COVID-19 or other viral infections?
   No, the focus remains on bacterial infections and microbiome-related conditions.

3. What challenges does rifaximin face in expanding its indications?
   Demonstrating efficacy and safety in new indications, resistance development, and regulatory hurdles.

4. How might generic competition affect rifaximin?
   Post-2024, generic versions could lower prices, potentially reducing revenue yet increasing access.

5. Which markets are the biggest for rifaximin?
   The US leads, followed by Europe and Japan, accounting for the majority of sales.

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References

[1] Food and Drug Administration (FDA). (2015). Rifaximin (Xifaxan) approval for travelers' diarrhea and hepatic encephalopathy.
[2] Allied Market Research. (2022). Global rifaximin market analysis, 2022-2030.
[3] European Medicines Agency (EMA). (2022). Guidelines on gut microbiome therapies.
[4] ClinicalTrials.gov. (2023). Rifaximin clinical trials list.