CLINICAL TRIALS PROFILE FOR BOSENTAN

All Clinical Trials for BOSENTAN

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00023296 ↗	Nitric Oxide and Transfusion Therapy for Sickle Cell Patients With Pulmonary Hypertension	Completed	Mallinckrodt	Phase 1	2001-07-27	This study will test whether inhaling nitric oxide (NO) gas mixed with room air can improve pulmonary hypertension (high blood pressure in the lungs) in patients with sickle cell anemia. Patients with sickle cell disease 18 years of age or older may be eligible to participate in one or more parts of this three-stage study, as follows: Stage 1 Patients undergo the following tests to determine the cause of their pulmonary hypertension: blood tests; echocardiogram (heart ultrasound); asthma test; oxygen breathing study with measurement of arterial blood oxygen levels; chest X-ray; lung scans; MRI of the heart; 6-minute walk test; night-time oxygen measurement while sleeping; and exercise studies. Stage 2 Patients have a detailed MRI evaluation of the heart and are admitted to the NIH Clinical Center intensive care unit (ICU) for the following test: A plastic tube is placed in a vein in the patient's arm and another tube is placed in a deeper neck or leg vein. A third tube is inserted through the vein into the heart and the lung artery to measure blood pressures in the heart and lungs directly. Following baseline measurements, three medications (inhaled oxygen, infused prostaglandin, and inhaled NO) are delivered for 2 hours each, separated by a 30-minute washout period. A small blood sample is drawn during the NO administration. Patients who cannot be treated with nitric oxide or for whom the treatment does not work may receive monthly exchange transfusions for 3 months. For this procedure, 3 to 5 five units of the patient's blood is removed and replaced with 3 to 5 units that do not have sickle hemoglobin. Some patients who do not respond to NO or exchange transfusions may receive an alternative therapy, such as oxygen, prostacyclin, L-arginine, bosentan or sidenafil. Stage 3 Patients remain in the ICU with catheters in place for another 24 hours. During this time they breathe NO. Lung pressures are measured every 4 hours and blood is drawn every 8 hours. They then stay in the hospital 1 more day for observation. Patients then breathe nitric oxide continuously for 2 months using a tank of gas that delivers the NO through tubes placed in the nose. They may do this at home on an outpatient basis or may remain in the hospital for the 2 months. Patients have an echocardiogram and blood tests every week and do a 6-minute walk test every 2 weeks....
NCT00023296 ↗	Nitric Oxide and Transfusion Therapy for Sickle Cell Patients With Pulmonary Hypertension	Completed	National Heart, Lung, and Blood Institute (NHLBI)	Phase 1	2001-07-27	This study will test whether inhaling nitric oxide (NO) gas mixed with room air can improve pulmonary hypertension (high blood pressure in the lungs) in patients with sickle cell anemia. Patients with sickle cell disease 18 years of age or older may be eligible to participate in one or more parts of this three-stage study, as follows: Stage 1 Patients undergo the following tests to determine the cause of their pulmonary hypertension: blood tests; echocardiogram (heart ultrasound); asthma test; oxygen breathing study with measurement of arterial blood oxygen levels; chest X-ray; lung scans; MRI of the heart; 6-minute walk test; night-time oxygen measurement while sleeping; and exercise studies. Stage 2 Patients have a detailed MRI evaluation of the heart and are admitted to the NIH Clinical Center intensive care unit (ICU) for the following test: A plastic tube is placed in a vein in the patient's arm and another tube is placed in a deeper neck or leg vein. A third tube is inserted through the vein into the heart and the lung artery to measure blood pressures in the heart and lungs directly. Following baseline measurements, three medications (inhaled oxygen, infused prostaglandin, and inhaled NO) are delivered for 2 hours each, separated by a 30-minute washout period. A small blood sample is drawn during the NO administration. Patients who cannot be treated with nitric oxide or for whom the treatment does not work may receive monthly exchange transfusions for 3 months. For this procedure, 3 to 5 five units of the patient's blood is removed and replaced with 3 to 5 units that do not have sickle hemoglobin. Some patients who do not respond to NO or exchange transfusions may receive an alternative therapy, such as oxygen, prostacyclin, L-arginine, bosentan or sidenafil. Stage 3 Patients remain in the ICU with catheters in place for another 24 hours. During this time they breathe NO. Lung pressures are measured every 4 hours and blood is drawn every 8 hours. They then stay in the hospital 1 more day for observation. Patients then breathe nitric oxide continuously for 2 months using a tank of gas that delivers the NO through tubes placed in the nose. They may do this at home on an outpatient basis or may remain in the hospital for the 2 months. Patients have an echocardiogram and blood tests every week and do a 6-minute walk test every 2 weeks....
NCT00070590 ↗	Efficacy and Safety of Oral Bosentan in Pulmonary Fibrosis Associated With Scleroderma	Completed	Actelion	Phase 2/Phase 3	2003-07-01	Clinical and experimental studies suggest that bosentan could delay the progression of interstitial lung disease (ILD) associated with systemic sclerosis (SSc), a condition for which no established efficacious treatment is available. The present trial investigates a possible use of oral bosentan, which is currently approved for the treatment of symptoms of pulmonary arterial hypertension (PAH) WHO Class III and IV, to a new category of patients suffering from ILD associated with SSc.
NCT00071461 ↗	Efficacy and Safety of Oral Bosentan in Patients With Idiopathic Pulmonary Fibrosis	Completed	Actelion	Phase 2/Phase 3	2003-08-01	Endothelin-1 (ET-1) is expressed in a variety of pulmonary pathological conditions including pulmonary vascular disease and pulmonary fibrosis. Bosentan (an oral dual ET-1 receptor antagonist) could delay the progression of idiopathic pulmonary fibrosis (IPF), a condition for which no established treatment is available. The present trial investigates a possible use of bosentan, which is currently approved for the treatment of symptoms of pulmonary arterial hypertension (PAH) WHO class III and IV, to a new category of patients suffering from IPF. It was decided to offer Open Label treatment (bosentan) for patients willing to continue in the BUILD 1 study.

Clinical Trial Conditions for BOSENTAN

Condition Name

Condition Name for BOSENTAN
Intervention	Trials
Pulmonary Arterial Hypertension	30
Pulmonary Hypertension	24
Hypertension, Pulmonary	8
Systemic Sclerosis	7

Condition MeSH

Condition MeSH for BOSENTAN
Intervention	Trials
Hypertension	69
Pulmonary Arterial Hypertension	47
Familial Primary Pulmonary Hypertension	43
Hypertension, Pulmonary	40

Clinical Trial Locations for BOSENTAN

Trials by Country

Trials by Country for BOSENTAN
Location	Trials
United States	399
Germany	41
Canada	36
France	32
Australia	28

Trials by US State

Trials by US State for BOSENTAN
Location	Trials
California	32
Texas	26
New York	23
Pennsylvania	21
Colorado	21

Clinical Trial Progress for BOSENTAN

Clinical Trial Phase

Clinical Trial Phase for BOSENTAN
Clinical Trial Phase	Trials
PHASE2	3
PHASE1	2
Phase 4	24

Clinical Trial Status

Clinical Trial Status for BOSENTAN
Clinical Trial Phase	Trials
Completed	78
Terminated	21
Unknown status	17

Clinical Trial Sponsors for BOSENTAN

Sponsor Name

Sponsor Name for BOSENTAN
Sponsor	Trials
Actelion	50
University of California, Los Angeles	5
Johns Hopkins University	4

Sponsor Type

Sponsor Type for BOSENTAN
Sponsor	Trials
Other	156
Industry	83
NIH	7

Clinical Trials Update, Market Analysis, and Projection for Bosentan

Last updated: October 27, 2025

Introduction

Bosentan, marketed under the brand name Tracleer among others, is an oral endothelin receptor antagonist approved predominantly for pulmonary arterial hypertension (PAH). Since its debut in 2001, Bosentan has played a pivotal role in the management of PAH, marking a significant milestone in treating this rare, life-threatening condition. As the pharmaceutical landscape evolves, continuous updates on clinical trial activity, market dynamics, and future projections remain vital for stakeholders. This article synthesizes recent clinical developments, analyzes current market trends, and forecasts Bosentan's trajectory over the upcoming years.

Clinical Trial Landscape and Updates

Ongoing and Recent Clinical Trials

Bosentan continues to attract research interest, primarily focusing on expanding its indications, optimizing dosing strategies, and understanding long-term safety profiles. According to ClinicalTrials.gov, numerous ongoing studies explore its utility beyond PAH, including potential applications in systemic sclerosis-associated PAH, congenital heart disease, and other vascular disorders. Notably:

• Bosentan in Systemic Sclerosis: A phase 3 trial (NCTXXXXXX) is evaluating its efficacy in reducing skin thickness and pulmonary involvement in systemic sclerosis, with preliminary results expected within the next year. This aligns with earlier findings suggesting vasculoprotective benefits.

• Combination Therapy Trials: Several studies assess Bosentan in combination with new PAH-targeting agents such as selexipag or riociguat. These trials aim to determine synergistic effects, optimize treatment regimens, and improve patient outcomes.

• Long-term Safety and Pharmacokinetics: Extended observational studies are providing insights into Bosentan's safety profile, focusing on hepatic toxicity and hematologic effects, critical for ongoing clinician confidence and patient management.

Regulatory Updates and Labeling Changes

The European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) regularly review Pharmacoepidemiological data to monitor Bosentan's safety profile. Recently, the FDA issued updates emphasizing hepatic monitoring protocols, reinforcing safety measures during therapy—a move consistent with the drug’s known hepatotoxicity risks. Such regulatory adaptations influence clinical trial designs and post-marketing surveillance strategies.

Market Analysis

Current Market Size and Regional Distribution

As of 2023, Bosentan remains a cornerstone in PAH management, with an estimated global market value of approximately $300 million[1]. The drug maintains strong market penetration across North America, Europe, and select Asian markets, driven by its efficacy, established safety data, and inclusion in multiple clinical guidelines.

Key regional insights include:

• North America: Dominating the market due to high diagnosis rates of PAH and robust healthcare infrastructure, supported by stringent reimbursement policies.

• Europe: Similar market size with expanding indications, particularly in systemic sclerosis, bolstering sales.

• Asia-Pacific: Growing market, underpinned by rising PAH prevalence and expanding healthcare access, though influenced by drug pricing and regulatory considerations.

Market Dynamics and Competitive Landscape

Bosentan's primary competitors include other endothelin receptor antagonists like ambrisentan and macitentan, which offer improved safety profiles and simplified dosing. However, Bosentan's advantages—such as proven long-term efficacy and extensive clinical data—help sustain its market share.

Current challenges include:

• Safety Concerns: Hepatotoxicity remains a significant issue, impacting prescribing habits.
• Generic Competition: Patent expirations are imminent or recent in key markets, leading to generic versions that threaten branded sales.
• Regulatory Hesitance: Stricter safety monitoring requirements influence market access and physician prescribing behaviors.

Future Market Projection

Forecasts suggest moderate growth, reaching approximately $450 million by 2027[2]. Growth drivers include:

• Extended Indications: Clinical trial successes in systemic sclerosis and congenital heart disease could broaden the patient base.
• Combination Therapies: Adoption of Bosentan as part of multi-drug regimens may stimulate sales, especially if demonstrated to improve clinical outcomes.
• Emerging Markets: Increasing awareness and diagnosis in low-to-middle-income countries will open new revenue streams, despite pricing challenges.

However, the rate of growth will likely be tempered by increasing competition, safety concerns, and pricing pressures. The global trend toward biosimilars and patent expirations will influence the competitive landscape over the next five years.

Future Projections and Strategic Outlook

The future of Bosentan hinges on its adaptation to evolving clinical standards and technology:

• Regulatory Expansion: Successful trials could lead to expanding indications, increasing market access.
• Personalized Medicine: Biomarker-driven patient selection may optimize therapy efficacy, boosting prescriber confidence.
• Combination Therapies: Demonstrating superior outcomes with combination regimens will be critical for maintaining market relevance.

From a commercial standpoint, companies investing in post-marketing surveillance and real-world evidence collection will strengthen their case for broader use and reimbursement. Moreover, leveraging digital health tools to monitor long-term safety profiles can mitigate regulatory risks.

Key Takeaways

• Clinical Development: Bosentan remains under active investigation, particularly for expanding its therapeutic scope. New clinical trials focusing on systemic sclerosis and combination protocols are poised to influence future treatment guidelines.

• Market Position: Despite generic competition and safety concerns, Bosentan maintains a significant market share, especially in regions with established PAH management protocols.

• Growth Drivers: Broadened indications, combination therapies, and emerging markets will fuel growth, although tempered by increased safety monitoring and competition.

• Strategic Focus: Continuous safety profiling, regulatory engagement, and exploration of new indications are essential for sustaining and expanding Bosentan's commercial viability.

• Long-term Outlook: With ongoing clinical validation and strategic positioning, Bosentan has the potential to retain a conservative but steady growth trajectory through 2027 and beyond.

FAQs

Q1: What are the primary safety concerns associated with Bosentan?
A1: Hepatotoxicity is the most significant safety concern, requiring regular liver function monitoring. Other adverse effects include anemia, headache, and edema.

Q2: How is Bosentan currently positioned compared to newer PAH therapies?
A2: While newer agents like macitentan and ambrisentan offer better safety profiles and simplified dosing, Bosentan retains a strong position due to its extensive clinical evidence and efficacy in long-term management.

Q3: Are there ongoing efforts to expand Bosentan's indications?
A3: Yes, multiple clinical trials are investigating its role in systemic sclerosis, congenital heart disease, and as part of combination therapies, aiming to broaden its therapeutic scope.

Q4: What impact will patent expirations have on Bosentan's market?
A4: Patent expirations will facilitate generic entry, exerting downward pressure on prices and potentially reducing branded sales. Strategic differentiation through clinical benefits will be necessary to sustain market share.

Q5: How might emerging biomarkers influence Bosentan's future use?
A5: Biomarker-driven patient selection could optimize therapeutic outcomes, reduce adverse effects, and enhance price competitiveness, thereby supporting long-term adoption.

References

[1] MarketWatch. Global Pulmonary Arterial Hypertension Drugs Market Forecast, 2020-2027.

[2] Allied Market Research. Pulmonary Arterial Hypertension (PAH) Drugs Market – Global Opportunity Analysis and Industry Forecast, 2020-2027.