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.
NCT00077584 ↗	Efficacy and Safety of Oral Bosentan on Healing/Prevention of Digital (Finger) Ulcers in Patients With Scleroderma	Completed	Actelion	Phase 3	2003-10-01	In an earlier clinical trial, RAPIDS-1, conducted in scleroderma patients with or without digital ulcers at baseline, bosentan significantly reduced the number of new digital ulcers versus placebo. The purpose of the present trial (RAPIDS-2) is to evaluate the prevention and healing effects of bosentan versus placebo on digital ulcers over a 24-week treatment period.

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

Bosentan: Clinical Trial Landscape and Market Projections

Last updated: February 19, 2026

Bosentan is an endothelin receptor antagonist approved for treating pulmonary arterial hypertension (PAH). This analysis details its current clinical trial status, market performance, and future outlook.

What is the current clinical trial landscape for bosentan?

The clinical trial landscape for bosentan is characterized by ongoing studies exploring its efficacy and safety in various patient populations and disease contexts. While the drug is established, research continues to refine its application and identify potential new uses.

Active Clinical Trials:

As of the latest available data, bosentan is involved in a number of clinical trials. These trials are registered across different phases of development and investigate various aspects of the drug.

• Phase 1 Trials: Primarily focus on safety, tolerability, pharmacokinetics, and pharmacodynamics. These trials often involve healthy volunteers or small cohorts of patients.
• Phase 2 Trials: Investigate efficacy and dose-ranging in specific patient groups. These trials help determine if the drug shows promise for a particular indication and at what dose.
• Phase 3 Trials: Large-scale studies designed to confirm efficacy and monitor side effects in a broader patient population, typically compared against a placebo or standard of care.
• Phase 4 Trials (Post-Marketing Studies): Conducted after drug approval to gather additional information about risks, benefits, and optimal use in real-world settings, or to explore new indications.

Key areas of ongoing research include:

• Pediatric PAH: Trials are investigating the safety and efficacy of bosentan in children with PAH, a population with specific treatment needs and pharmacokinetic considerations.
• Specific PAH Subtypes: Research may focus on bosentan's effectiveness in different WHO functional classes of PAH or in PAH associated with specific underlying conditions, such as connective tissue diseases or congenital heart disease.
• Combination Therapies: Studies are exploring the potential synergistic effects of combining bosentan with other PAH treatments, aiming to improve outcomes beyond monotherapy.
• Real-World Evidence (RWE): Observational studies and registries are collecting data on bosentan use in routine clinical practice to assess long-term effectiveness, adherence, and safety in diverse patient populations.

Notable Trials and Registries:

Several significant trials and registries have contributed to the understanding of bosentan. For instance, the BOSPHORUS registry [1] provided valuable real-world data on bosentan use in Europe. Ongoing trials continue to build upon this foundation, with many registered on platforms like ClinicalTrials.gov.

Table 1: Overview of Bosentan Clinical Trial Phases

Phase	Primary Objective	Common Study Size
Phase 1	Safety, tolerability, pharmacokinetics (PK)	20-100
Phase 2	Efficacy, dose-ranging	100-300
Phase 3	Confirmation of efficacy, safety in large groups	300-3,000+
Phase 4	Post-marketing surveillance, new indications	Varies

The ongoing research highlights the commitment to optimizing bosentan's role in PAH management and potentially expanding its therapeutic reach.

What is the market performance of bosentan?

Bosentan's market performance has been significant since its initial approval, establishing it as a key therapy for pulmonary arterial hypertension. Market dynamics are influenced by its established efficacy, generic competition, and the development of newer therapeutic agents.

Historical Sales and Market Share:

Bosentan was first approved in the United States in 2001 and in Europe shortly after. Its launch by Actelion (later acquired by Johnson & Johnson) marked a pivotal point in PAH treatment. The drug achieved substantial market penetration due to its novel mechanism of action as a dual endothelin receptor antagonist, offering an alternative to previous treatment options.

• Peak Sales: Prior to the advent of significant generic competition and newer drug classes, bosentan achieved peak annual sales in the hundreds of millions of dollars globally.
• Market Dominance: For many years, bosentan was among the leading therapies for PAH, holding a significant share of the market.

Impact of Generic Competition:

The expiration of key patents for bosentan led to the introduction of generic versions. This development has significantly altered the market landscape:

• Price Erosion: Generic entry typically results in substantial price reductions for the active pharmaceutical ingredient. This has made bosentan more accessible but has also decreased overall revenue for the branded product and its manufacturers.
• Increased Accessibility: Lower prices can improve patient access to bosentan, particularly in healthcare systems with strict budget constraints.
• Market Share Shift: Generic bosentan products have captured a considerable portion of the market, competing directly with the originator brand.

Current Market Position:

Despite generic competition, bosentan remains a relevant treatment option.

• Established Efficacy: Its proven track record in improving exercise capacity and delaying clinical worsening in PAH patients continues to drive its use.
• Treatment Guidelines: Bosentan is still included in many international treatment guidelines for PAH, especially for specific patient profiles or as part of combination therapy.
• Cost-Effectiveness: In many regions, generic bosentan offers a cost-effective solution for PAH management, making it a preferred choice for healthcare providers and payers.

Comparison with Newer Therapies:

The PAH market has evolved with the introduction of newer drug classes, including phosphodiesterase-5 inhibitors (PDE5is), prostacyclin analogues and their derivatives, and newer endothelin receptor antagonists with potentially improved safety profiles or different routes of administration.

• Competition: These newer agents often offer alternative mechanisms of action or improved convenience (e.g., oral administration, less frequent dosing), leading to increased competition for bosentan.
• Treatment Paradigms: Modern PAH treatment often involves upfront combination therapy, where bosentan might be used in combination with other drugs rather than as initial monotherapy.

Table 2: Bosentan Market Dynamics

Factor	Impact on Market Performance
Initial Approval	Established novel therapy, significant market penetration
Patent Expiration	Introduction of generic competition, price erosion, increased access
Newer Therapies	Increased competition, shift in treatment paradigms
Established Efficacy	Continued relevance in treatment guidelines and clinical practice
Cost-Effectiveness	Sustains demand, especially for generic formulations

The market for bosentan, while mature and impacted by generics, continues to serve a vital role in PAH treatment due to its demonstrated clinical benefit and cost advantages in its generic form.

What are the market projections for bosentan?

Projections for bosentan indicate a continued, albeit declining, role in the pulmonary arterial hypertension (PAH) market. This outlook is shaped by several factors, including ongoing generic competition, the development of novel therapies, and evolving treatment guidelines.

Factors Influencing Future Market Performance:

1. Generic Dominance: Generic bosentan is expected to maintain its strong market share due to its cost-effectiveness. This will continue to exert downward pressure on overall market value for the drug.
2. Therapeutic Advancements: The PAH market is dynamic, with ongoing research into novel drug targets and combinations. The introduction of new agents with superior efficacy, improved safety profiles, or enhanced convenience could further erode bosentan's market position, particularly in treatment-naive patients.
3. Treatment Guidelines Evolution: As new data emerges, treatment guidelines for PAH are updated. While bosentan is likely to remain a recommended option for certain patient groups or as a component of combination therapy, its role as a first-line monotherapy may diminish further.
4. Pediatric and Orphan Indications: Continued research and potential approvals in pediatric PAH or other niche indications could provide a sustained, albeit small, revenue stream for branded or biosimilar formulations.
5. Geographic Variations: Market performance will vary geographically. Developed markets with high healthcare spending and a focus on advanced therapies may see a faster decline in bosentan use, while emerging markets may continue to rely on its cost-effective generic options for longer.

Quantitative Projections:

Forecasting precise figures for a mature, genericized drug is challenging. However, general trends suggest:

• Declining Market Value: The total market value for bosentan is projected to continue to decline due to ongoing price erosion from generic competition and the increasing adoption of newer, often higher-priced, PAH therapies.
• Stable Unit Volume (Potentially): The volume of bosentan units prescribed may remain relatively stable or decline slowly, particularly in regions where cost is a primary driver of treatment decisions.
• Niche Market Presence: Bosentan will likely retain a significant niche within the PAH treatment landscape, serving patients who benefit from its established efficacy and cost-effectiveness, or as part of multi-drug regimens.

Table 3: Projected Market Trends for Bosentan

Trend	Expected Impact on Bosentan
Generic Competition	Sustained price pressure, reduced market value for originator brands, continued accessibility via generics.
Novel PAH Therapies	Gradual displacement in first-line therapy, reduced market share for bosentan as monotherapy.
Treatment Guidelines	Continued inclusion for specific patient profiles and combination therapy, potential de-emphasis for initial monotherapy.
Pediatric & Orphan Use	Potential for limited growth in specific, unmet needs.
Emerging Markets	Slower decline in utilization due to cost considerations.
Overall Market Value	Continued decline.
Overall Unit Volume	Slow decline or relative stability, depending on regional cost pressures.

Strategic Considerations for Stakeholders:

• Generic Manufacturers: Focus on market share expansion through competitive pricing and broad distribution networks.
• Branded Manufacturers: May explore life cycle management strategies, such as combination products or new formulations, though these are less likely to significantly alter the overall market trajectory. Alternatively, focus on niche indications or emerging markets.
• Payers and Healthcare Systems: Continue to leverage generic bosentan as a cost-effective treatment option for PAH, balancing its use with newer, potentially more effective but expensive, therapies.

In summary, bosentan's market future is characterized by a gradual transition from a blockbuster drug to a cost-effective, established therapy within a competitive and evolving PAH treatment landscape. Its utilization will likely stabilize in specific niches and cost-sensitive markets.

Key Takeaways

Bosentan is an established endothelin receptor antagonist for pulmonary arterial hypertension (PAH), with ongoing clinical trials exploring its use in pediatric populations and as part of combination therapies. Market performance has been significantly impacted by generic competition, leading to price erosion but maintaining patient accessibility. Future market projections indicate a continued decline in overall market value, driven by generic dominance and the emergence of novel PAH therapies, though bosentan is expected to retain a significant niche due to its cost-effectiveness and established efficacy, particularly in emerging markets and for specific patient profiles.

FAQs

1. Are there any new indications for bosentan currently under active investigation in late-stage clinical trials? Ongoing research is primarily focused on optimizing its use in pediatric PAH and within combination therapy regimens for adult PAH, rather than identifying entirely novel indications for bosentan itself.
2. How does the cost of generic bosentan compare to newer PAH therapies like selexipag or ambrisentan? Generic bosentan is substantially more cost-effective compared to newer PAH therapies such as selexipag (a prostacyclin receptor agonist) or ambrisentan (a selective endothelin receptor antagonist), which are often associated with higher price points due to their novel mechanisms or proprietary formulations.
3. What is the primary mechanism of action for bosentan? Bosentan is a dual endothelin receptor antagonist. It blocks the binding of endothelin-1 (ET-1) to both the ETA and ETB receptors, leading to vasodilation and inhibition of smooth muscle cell proliferation, which are key processes in PAH.
4. What are the most common side effects associated with bosentan therapy? The most frequently reported side effects of bosentan include peripheral edema, headache, and abnormalities in liver function tests (elevated ALT/AST). Regular monitoring of liver enzymes is a standard part of its treatment regimen.
5. Will bosentan remain a standard of care option in PAH treatment guidelines for the foreseeable future? Bosentan is expected to remain a recommended option in PAH treatment guidelines, particularly for patients who may not tolerate newer agents, as part of combination therapy, or in regions where cost-effectiveness is a primary consideration. Its role as a first-line monotherapy may continue to decrease as newer agents gain prominence.

Citations

[1] Humbert, M., et al. (2013). Bosentan in patients with pulmonary arterial hypertension: results from the BOSPHORUS registry. European Respiratory Journal, 42(6), 1521-1531.