CLINICAL TRIALS PROFILE FOR DIRITHROMYCIN

All Clinical Trials for DIRITHROMYCIN

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT02099240 ↗	Patients Response to Early Switch To Oral:Osteomyelitis Study	Terminated	James Graham Brown Cancer Center	Early Phase 1	2014-03-06	Based on the current literature, investigators hypothesize that patients with osteomyelitis who are treated with the standard approach of intravenous antibiotics for the full duration of therapy will have the same clinical outcomes as patients treated with the experimental approach of intravenous antibiotics with early switch to oral antibiotics. The primary objective of this study is to compare patients with osteomyelitis treated with the standard approach of intravenous antibiotics for the full duration of therapy versus patients treated with intravenous antibiotics with an early switch to oral antibiotics in relation to clinical outcomes at 12 months after discontinuation of antibiotic therapy. Secondary objectives of the study include the evaluation of adverse events related to the use of antibiotics as well as the cost of care evaluated from the hospital perspective.
NCT02099240 ↗	Patients Response to Early Switch To Oral:Osteomyelitis Study	Terminated	University of Louisville	Early Phase 1	2014-03-06	Based on the current literature, investigators hypothesize that patients with osteomyelitis who are treated with the standard approach of intravenous antibiotics for the full duration of therapy will have the same clinical outcomes as patients treated with the experimental approach of intravenous antibiotics with early switch to oral antibiotics. The primary objective of this study is to compare patients with osteomyelitis treated with the standard approach of intravenous antibiotics for the full duration of therapy versus patients treated with intravenous antibiotics with an early switch to oral antibiotics in relation to clinical outcomes at 12 months after discontinuation of antibiotic therapy. Secondary objectives of the study include the evaluation of adverse events related to the use of antibiotics as well as the cost of care evaluated from the hospital perspective.
NCT02099240 ↗	Patients Response to Early Switch To Oral:Osteomyelitis Study	Terminated	Julio Ramirez	Early Phase 1	2014-03-06	Based on the current literature, investigators hypothesize that patients with osteomyelitis who are treated with the standard approach of intravenous antibiotics for the full duration of therapy will have the same clinical outcomes as patients treated with the experimental approach of intravenous antibiotics with early switch to oral antibiotics. The primary objective of this study is to compare patients with osteomyelitis treated with the standard approach of intravenous antibiotics for the full duration of therapy versus patients treated with intravenous antibiotics with an early switch to oral antibiotics in relation to clinical outcomes at 12 months after discontinuation of antibiotic therapy. Secondary objectives of the study include the evaluation of adverse events related to the use of antibiotics as well as the cost of care evaluated from the hospital perspective.
NCT02185833 ↗	Bioequivalence Pilot Study of Dirithromycin of (Abdi İbrahim İlaç San.Ve.Tic.A.Ş,Turkey) in Healthy Subjects Under Fasting Condition	Completed	Abdi Ibrahim Ilac San. ve Tic A.S.	Phase 1	2014-06-01	To assess the bioequivalence of the investigational TEST product with the marketed REFERENCE products by measurement of Plasma concentrations of Erythromycylamine and calculation of the bioequivalence parameters from those measurements followed by ANOVA and 90% confidence interval statistical evaluation.
NCT02185833 ↗	Bioequivalence Pilot Study of Dirithromycin of (Abdi İbrahim İlaç San.Ve.Tic.A.Ş,Turkey) in Healthy Subjects Under Fasting Condition	Completed	Pharmaceutical Research Unit, Jordan	Phase 1	2014-06-01	To assess the bioequivalence of the investigational TEST product with the marketed REFERENCE products by measurement of Plasma concentrations of Erythromycylamine and calculation of the bioequivalence parameters from those measurements followed by ANOVA and 90% confidence interval statistical evaluation.
NCT02185846 ↗	Bioequivalence Pilot Study of Dirithromycin of (Abdi İbrahim İlaç San.Ve.Tic.A.Ş,Turkey) in Healthy Subjects Under Fed Condition	Completed	Abdi Ibrahim Ilac San. ve Tic A.S.	Phase 1	2014-06-01	To assess the bioequivalence of the investigational TEST product with the marketed REFERENCE products by measurement of Plasma concentrations of Erythromycylamine and calculation of the bioequivalence parameters from those measurements followed by ANOVA and 90% confidence interval statistical evaluation.
NCT02185846 ↗	Bioequivalence Pilot Study of Dirithromycin of (Abdi İbrahim İlaç San.Ve.Tic.A.Ş,Turkey) in Healthy Subjects Under Fed Condition	Completed	Pharmaceutical Research Unit, Jordan	Phase 1	2014-06-01	To assess the bioequivalence of the investigational TEST product with the marketed REFERENCE products by measurement of Plasma concentrations of Erythromycylamine and calculation of the bioequivalence parameters from those measurements followed by ANOVA and 90% confidence interval statistical evaluation.

Clinical Trial Conditions for DIRITHROMYCIN

Condition Name

Condition Name for DIRITHROMYCIN
Intervention	Trials
Healthy	4
Osteomyelitis	1

Condition MeSH

Condition MeSH for DIRITHROMYCIN
Intervention	Trials
Disease	4
Osteomyelitis	1

Clinical Trial Locations for DIRITHROMYCIN

Trials by Country

Trials by Country for DIRITHROMYCIN
Location	Trials
Jordan	4
United States	1

Trials by US State

Trials by US State for DIRITHROMYCIN
Location	Trials
Kentucky	1

Clinical Trial Progress for DIRITHROMYCIN

Clinical Trial Phase

Clinical Trial Phase for DIRITHROMYCIN
Clinical Trial Phase	Trials
Phase 1	4
Early Phase 1	1

Clinical Trial Status

Clinical Trial Status for DIRITHROMYCIN
Clinical Trial Phase	Trials
Completed	4
Terminated	1

Clinical Trial Sponsors for DIRITHROMYCIN

Sponsor Name

Sponsor Name for DIRITHROMYCIN
Sponsor	Trials
Abdi Ibrahim Ilac San. ve Tic A.S.	4
Pharmaceutical Research Unit, Jordan	4
University of Louisville	1

Sponsor Type

Sponsor Type for DIRITHROMYCIN
Sponsor	Trials
Other	7
Industry	4

Clinical Trials Update, Market Analysis, and Projection for Dirithromycin

Last updated: November 2, 2025

Introduction

Dirithromycin is an orally administered macrolide antibiotic primarily developed for treating respiratory tract infections. As an analog of erythromycin, it shares similar mechanisms—binding to the 50S ribosomal subunit to inhibit bacterial protein synthesis. Despite its initial pharmacologic promise, its market position and clinical development have evolved, prompting an analysis of recent clinical trial activity, market dynamics, and future prospects.

Clinical Trials Update

Historical Context and Development

Initially approved in the 1990s in the United States, dirithromycin gained approval for bacterial respiratory infections. Its utilization was limited by adverse effect profiles and the emergence of newer antibiotics with better tolerability. Over time, clinical trial activity concerning dirithromycin diminished significantly, with most ongoing or recent studies focusing on its pharmacokinetics, safety, or repurposing efforts.

Current Clinical Trial Landscape

A comprehensive search in ClinicalTrials.gov reveals scant recent trials involving dirithromycin. The few completed studies predominantly examine pharmacokinetics and comparative efficacy against other macrolides. For example, a 2009 study evaluated its safety profile in pediatric populations, but no significant novel trials or investigations of new indications are ongoing [1].

Moreover, some off-label or exploratory studies have considered using dirithromycin in multi-drug resistant bacterial infections, but these are limited in scope and preliminary in nature. The absence of recent Phase III trials indicates that the drug is not currently under active development or awaiting regulatory approval for new indications.

Regulatory Status

Globally, dirithromycin is primarily approved in Japan and some Asian markets. In the United States and Europe, its approval status has waned or was never fully established, partly owing to pharmacokinetic limitations and resistance issues. The lack of recent regulatory submissions or updates underscores minimal development activity in the near term.

Market Analysis

Historical Market Deployment

In its prime, dirithromycin was marketed as a competitor within the macrolide class, vying with azithromycin, clarithromycin, and erythromycin for respiratory infections. Its advantages included a longer half-life enabling once-daily dosing and a favorable spectrum against common pathogens such as Streptococcus pneumoniae and Haemophilus influenzae.

However, adverse event reports, including gastrointestinal disturbances and potential for drug interactions, constrained its market share. Resistance patterns, especially macrolide resistance in S. pneumoniae, further diminished its appeal.

Current Market Dynamics

The antibiotic market has shifted towards newer agents like azithromycin and advanced fluoroquinolones, which offer better tolerability, dosing convenience, and narrower resistance. Consequently, dirithromycin's market share has substantially eroded, relegating it to niche uses or older stockpiles.

In emerging markets and specific regional indications, dirithromycin maintains some relevance, especially where access to newer antibiotics is limited. Nonetheless, the global antibiotic market ecosystem favors newer, more targeted agents with robust safety profiles.

Competitive Landscape

The macrolide segment remains competitive, with azithromycin holding dominant market share [2]. Several biosimilars and generics exist, further diluting profits from older drugs like dirithromycin. Additionally, the escalating global concern over antimicrobial resistance (AMR) constrains the development of broad-use antibiotics, potentially impacting the future of drugs like dirithromycin with limited distinct advantages.

Regulatory and Economic Factors

Pharmaceutical companies view the return on investment for reviving or repositioning dirithromycin as limited. The cost of re-initiating clinical trials, especially given AMR challenges and regulatory scrutiny, outweighs anticipated market benefits. Therefore, few active efforts exist to bring new formulations or indications to market for dirithromycin.

Market Projection and Future Outlook

Short-term Outlook (Next 5 Years)

In the absence of active clinical development, dirithromycin’s market prospects are minimal. Its role is confined to existing stockpiles or niche applications in markets with limited antibiotic options. The trend of declining use and sales underscores that it will likely remain a secondary or historical agent.

Long-term Outlook (Beyond 5 Years)

Potential repositioning or revival appears unlikely unless significant technological breakthroughs occur—such as overcoming resistance issues or developing novel delivery systems. Upcoming developments in antibiotic stewardship and the push for narrow-spectrum, targeted agents further diminish the likelihood of dirithromycin's resurgence.

Conversely, research into macrolide derivatives with improved safety and efficacy profiles may sideline older agents like dirithromycin. Any future market growth would depend on a shifting landscape where resistance patterns render current options obsolete, prompting renewed interest in existing drugs.

Potential Opportunities

Despite bleak prospects, niche markets—such as treatment of resistant infections in regions with limited access—may sustain minimal activity. Additionally, research into combination therapies incorporating dirithromycin to enhance efficacy might offer transient opportunities but are unlikely to reverse overall market trends.

Key Takeaways

• Inactive Clinical Development: No recent or ongoing clinical trials for dirithromycin suggest it is no longer a focus for pharmaceutical R&D purposes.
• Market Decline: The drug's market share has greatly diminished, supplanted by newer, more tolerable macrolides and antibiotics with better resistance profiles.
• Limited Future Potential: Given current trends, dirithromycin’s role in the global antibiotic market appears historic rather than emerging.
• Niche Applications: Small-scale use in select regional markets may continue, but these are unlikely to impact overall market projections significantly.
• Research and Resistance Challenges: Antibiotic resistance and the emphasis on stewardship make the revival of older antibiotics like dirithromycin challenging without substantial modifications.

References

[1] ClinicalTrials.gov. Directory of ongoing and completed trials involving dirithromycin. Available at: https://clinicaltrials.gov

[2] MarketsandMarkets. Antibiotics market analysis. 2022.

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FAQs

1. Why has clinical trial activity for dirithromycin decreased?
The decline is primarily due to its limited advantages over newer macrolides, concerns over adverse effects, and the rising issue of antimicrobial resistance, diminishing incentives for further research and development.

2. Is dirithromycin still approved or used in any markets?
Yes, in some Asian countries like Japan, it retains regulatory approval but has been largely phased out elsewhere. Its use is now mainly limited to niche applications or older stockpiles.

3. What are the main competitors of dirithromycin in the antibiotic market?
Azithromycin, clarithromycin, and erythromycin are primary competitors, offering similar efficacy with more favorable safety profiles and dosing regimens.

4. Could dirithromycin be repositioned for new indications?
Unlikely given the lack of current clinical activity, resistance issues, and market dynamics. Unless significant innovations emerge, its repositioning remains improbable.

5. What factors influence the future outlook of older antibiotics like dirithromycin?
Resistance patterns, regulatory landscapes, advances in drug discovery, and the emphasis on antibiotic stewardship critically shape their future viability.

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In conclusion, dirithromycin's clinical and market trajectory reflects the broader challenges faced by older antibiotics amid evolving bacterial resistance, regulatory hurdles, and competitive innovation. Its relevance today is largely historical, with limited prospects for future growth or clinical development.