Giant Cell Arteritis (GCA)Phase 2BOSICARTNCT06957002
Bosentan in the Treatment of Giant Cell Arteritis
A Phase 2 study testing Bosentan and Glucocorticoids in people with Giant Cell Arteritis (GCA), run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
Trial summary
The purpose of this study is to determine whether a treatment with 3 months of bosentan associated to standard therapy might be superior to glucocorticoids alone in term of failure free survival at 12 months Read more about this study
- Who is it for?
- Ages 50 years and older
- Conditions the study is for
- Giant Cell Arteritis (GCA)
- What is being tested?
- Bosentan and Glucocorticoids
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteFrance
- Study dates
- Jun 2026to Jun 2030
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 50 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients having given their written informed consent prior to participation in the study
- Patients affiliated with social security or CMU (profit or being entitled)
- Diagnosis of GCA, as defined by the revised GCA diagnosis criteria. Patients must satisfy criteria 1-2-3 and 4 (irrespective of time):
- Age ≥50 years at disease onset
- History of erythrocyte sedimentation rate (ESR) ≥ 50 mm/h or CRP ≥ 20 mg/L (not mandatory if TAB is positive: see below)
- At least one of the following:
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- unequivocal cranial symptoms of GCA (new onset headache, scalp tenderness, jaw claudication, temporal artery abnormality, ischemia-related vision loss)
- unequivocal symptoms of polymyalgia rheumatica (PMR)
- At least one of the following:
- Temporal artery biopsy (TAB) compatible with the diagnosis of GCA (non-necrotizing vasculitis with a predominance of mononuclear cell infiltration or granulomatous inflammation, usually with multinucleated giant cells)
- Evidence of large vessel vasculitis:
- angio-CT or angio-MRI: thickened and/or contrast-enhanced arteries especially aorta (≥2mm) and epiaortic arteries (≥1mm) and contrast enhanced arteries in T1-weighted sequences
- or PET scan: ≥ grade 2 (from 0 to 3) tracer uptake on large arteries
- At least a sign of active GCA within the 2 weeks prior to randomisation. Active GCA is defined by ESR ≥30 mm/h or CRP ≥10 mg/L and at least one of the following:
- unequivocal cranial symptoms of GCA (new onset localized headache, scalp or temporal artery tenderness, ischemia-related vision loss, or otherwise unexplained mouth or jaw pain upon mastication)
- unequivocal symptoms of PMR, defined as shoulder and/or hip girdle pain associated with inflammatory stiffness
- other features judged by the clinical investigator to be consistent with GCA or PMR flares
- Menopausal women (no gynaecological cycle over the past two years), or women who had a gynaecological cycle within previous 24 months (non-menopausal women) only if they have (1) an effective non hormonal contraceptive method throughout study and (2) a negative urinary beta-hCG test at inclusion.
Who cannot join
- Patients under maintenance of justice, wardship or legal guardianship
- Patient unable to give written informed consent prior to participation in the study
- Patients included in other investigational therapeutic study within the previous 3 months
- Patients suspected not to be observant to the proposed treatments
- Weight <40 Kg or > 100 Kg
- Moderate to severe hepatic impairment, i.e., Child-Pugh class B or C. History of chronic alcohol abuse (consumption > 20 g/day)
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- Severe chronic heart failure or severe systolic dysfunction
- Recent (< 3 months) or incoming surgery requiring a general anaesthesia
- History of stem cell or organ transplantation (except corneas if performed more than 3 months prior inclusion)
- Hypersensitivity to bosentan or one of its excipients
- Prior treatment with any of the following:
- Tocilizumab or methotrexate or secukinumab within 12 weeks preceding inclusion
- Cell-depleting agents (i.e., anti-CD20)
- Alkylating agents including cyclophosphamide
- Hydroxychloroquine, cyclosporine A, dapsone, azathioprine, mycophenolate mofetil or janus kinase inhibitors within 4 weeks preceding inclusion
- Tumor necrosis factor inhibitors within 8 weeks preceding inclusion
- Anakinra within 1 week preceding inclusion
- Ongoing treatment with glibenclamide, fluconazole and rifampicin. Concomitant administration of both a CYP3A4 inhibitor or a CYP2C9 inhibitor
- Long-course systemic glucocorticoid therapy for other conditions than GCA or PMR
- Laboratory abnormalities: AST or ALT >3 x upper limit of normal (ULN)
- Infections:
- Active hepatitis B or C
- HIV infection
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
France1 site
Unité de Recherche Clinique, Entrepôts de données et Pharmacologie GHU Paris Centre
Paris, 75005
Alexis REGENT, MD/PhD, 01 58 41 14 55 ext. +33, alexis.regent@aphp.fr
Luc Mouthon, MD, PhD, 01 58 41 20 31 ext. +33, luc.mouthon@aphp.fr
About this study
Official title: Bosentan in the Treatment of Giant Cell Arteritis. Multicenter, Randomized, Controlled, Superiority Phase II Trial Comparing a Combination of Bosentan and Glucocorticoids Versus Glucocorticoids Alone in the Treatment of Patients With GCA
The purpose of this study is to determine whether a treatment with 3 months of bosentan associated to standard therapy might be superior to glucocorticoids alone in term of failure free survival at 12 months
Read the detailed description
Giant cell arteritis (GCA) is the most common vasculitis in individuals over the age of 50. It is characterized by inflammation of large vessels, including the aorta and its main branches. Patients experience headaches, scalp tenderness, joint pain, and general symptoms such as weight loss, fatigue, and fever. More rarely, unilateral or bilateral visual acuity is impaired. At the biological level, an increase in inflammatory markers, such as C-reactive protein (CRP), is observed.
Glucocorticoids (GCs) are the cornerstone of GCA treatment and are usually administered for 12 to 18 months to prevent relapse, sometimes longer. However, most patients develop significant adverse effects associated with GCs, including hypertension, arterial disease, diabetes, osteoporosis, and infections. As a result, various strategies targeting the inflammatory process have been developed to reduce GC use. For example, methotrexate has been shown to be a modestly effective GC-sparing treatment. A 12-month course of tocilizumab (TCZ), an interleukin-6 (IL-6) receptor antagonist, has also been shown to induce and maintain remission of GCA, with a significant GC-sparing effect. However, only 45% of patients remained in long-term remission after discontinuing tocilizumab.
In patients with GCA, in addition to lymphocyte (white blood cell) activation, the investigator observed increased proliferative properties of vascular smooth muscle cells (VSMCs), obtained from temporal artery biopsies at the time of diagnosis. This proliferation and migration of VSMCs are promoted by endothelin-1 (ET-1), a molecule expressed in the walls of diseased arteries. Thus, ET-1 contributes to vessel lumen narrowing and complete obstruction. It was found that plasma ET-1 concentrations were higher in patients with visual ischemic complications. Additionally, an association was found between endothelin expression in temporal artery biopsies at baseline and therapeutic response at month six.
Bosentan has been marketed since 2002 for the management of patients with pulmonary arterial hypertension. This vasodilating drug is an endothelin (ET-1) receptor antagonist.
The investigator hypothesize that a 3-month course of treatment with bosentan, an endothelin receptor antagonist, combined with standard therapy, could be more effective than glucocorticoids (GCs) alone, reducing the risk of relapse and the current adverse effects, thereby improving relapse-free survival at 12 months.
- Conditions
- Giant Cell Arteritis (GCA)
- Being tested
- Bosentan, Glucocorticoids
- Keywords
- Giant Cell Arteritis, Bosentan
- Medical subject headings
- Giant Cell Arteritis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
BosentanDrug
Bosentan : 62.5 mg twice a day for 4 weeks and 125 mg twice a day during 9 weeks (treatment length 3 months)
GlucocorticoidsDrug
prespecified GC tapering schedule
| Study group | Role | What they receive |
|---|---|---|
| Bosentan + Glucocorticoids | Experimental | Bosentan : 62.5 mg bid for 4 weeks and 125 mg bid during 9 additional weeks Glucocorticoids : prespecified GC tapering schedule Receives: Drug: Bosentan |
| Glucocorticoids | Other | prespecified GC tapering schedule Receives: Drug: Glucocorticoids |
What is being measured
The primary outcome is the main question the study is designed to answer.
Failure free survival at Week 52
A failure is defined by the occurrence of a relapse or the impossibility to decrease Glucocorticoids according to the predefined scheduled Glucocorticoids scheme.
Measured: 12 months ( Week 52)
Secondary outcomes (11)
Proportion of new ischemic event
Measured: 12 months (Week 52)
Proportion of patients in remission without prednisone
Proportion of patients in remission without prednisone
Measured: 12 months (Week 52)
Proportion of patients in remission with prednisone ≤5 mg/day
Measured: 12 months (Week 52)
Cumulative dose of prednisone
Measured: 12 months (Week 52)
Proportion of patient in remission
Proportion of patient in remission
Measured: 2 years
Proportion of patients relapsing
Proportion of patients relapsing
Measured: year 1 to year 2
Proportion of patients receiving Glucocorticoids
Measured: 2 years
Quality of life measured by the "Health Assessment Questionnaire" (HAQ)
HAQ (Health Assessment Questionnaire) is a functional disability tool specific to rheumatoid arthritis. The assessment covers the past week and 8 domains of physical activity. For each area of activity, 2 to 3 items are described. Each item can be modified with aids. Only items with a specified response or aid are taken into account. Scores range from 0 (no impact) to 3 (maximum impact).
Measured: at Week 26 and Week 52
Quality of life measured by the "Short Form 36 Questionnaire" (SF36)
To score the SF-36, scales are standardized with a scoring algorithm or by the SF-36 (v2) scoring software to obtain a score ranging from 0 to 100. Higher scores indicate better health status, and a mean score of 50 has been articulated as a normative value for all scales
Measured: at Week 26 and Week 52
Frequency and type of side effects
Frequency and type of side effects
Measured: within 1 year after inclusion
Exploratory criteria
Compare the remodeling cytokines (pentraxin 3, osteoprotegerin, osteopontin, osteocalcin, thrombomodulin, HGF, endothelin, IL-6, TGF-β MMP-3)
Measured: At the beginning of the study and in both groups at Week 13 and Week 52
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 May 2025
- Study startJun 2026 (estimated)
- Primary completionJun 2029 (estimated)
- Study completionJun 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Giant Cell Arteritis (GCA)Studies of the same condition, open and under way.
- More trials run by Assistance Publique - Hôpitaux de ParisThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Assistance Publique - Hôpitaux de Paris
- Sponsor type
- University, hospital or other
- Collaborators
- URC-CIC Paris Descartes Necker Cochin
- Responsible party
- Sponsor
- Investigators
- Luc MOUTHON, Pr, Study director, Hôpital Cochin, Department of Internal Medicine - 75014, Paris
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06957002
- Sponsor's protocol ID
- P200041
- Other IDs
- 2024-517030-17
- Acronym
- BOSICART
- Status last verified
- Apr 2026
- First submitted
- 24 Mar 2025
- Last updated
- 6 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Bosentan in the Treatment of Giant Cell Arteritis. Multicenter, Randomized, Controlled, Superiority Phase II Trial Comparing a Combination of Bosentan and Glucocorticoids Versus Glucocorticoids Alone in the Treatment of Patients With GCA
- ClinicalTrials.gov ID
- NCT06957002
- Acronym / sponsor ID
- BOSICART / P200041
- Conditions
- Giant Cell Arteritis (GCA)
- Keywords
- Giant Cell Arteritis, Bosentan
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Assistance Publique - Hôpitaux de ParisUniversity, hospital or other
- Collaborators
- URC-CIC Paris Descartes Necker Cochin
- Study start
- Jun 2026 (estimated)
- Primary completion
- Jun 2029 (estimated)
- Study completion
- Jun 2030 (estimated)
- First posted
- 4 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to determine whether a treatment with 3 months of bosentan associated to standard therapy might be superior to glucocorticoids alone in term of failure free survival at 12 months
Detailed description
Giant cell arteritis (GCA) is the most common vasculitis in individuals over the age of 50. It is characterized by inflammation of large vessels, including the aorta and its main branches. Patients experience headaches, scalp tenderness, joint pain, and general symptoms such as weight loss, fatigue, and fever. More rarely, unilateral or bilateral visual acuity is impaired. At the biological level, an increase in inflammatory markers, such as C-reactive protein (CRP), is observed.
Glucocorticoids (GCs) are the cornerstone of GCA treatment and are usually administered for 12 to 18 months to prevent relapse, sometimes longer. However, most patients develop significant adverse effects associated with GCs, including hypertension, arterial disease, diabetes, osteoporosis, and infections. As a result, various strategies targeting the inflammatory process have been developed to reduce GC use. For example, methotrexate has been shown to be a modestly effective GC-sparing treatment. A 12-month course of tocilizumab (TCZ), an interleukin-6 (IL-6) receptor antagonist, has also been shown to induce and maintain remission of GCA, with a significant GC-sparing effect. However, only 45% of patients remained in long-term remission after discontinuing tocilizumab.
In patients with GCA, in addition to lymphocyte (white blood cell) activation, the investigator observed increased proliferative properties of vascular smooth muscle cells (VSMCs), obtained from temporal artery biopsies at the time of diagnosis. This proliferation and migration of VSMCs are promoted by endothelin-1 (ET-1), a molecule expressed in the walls of diseased arteries. Thus, ET-1 contributes to vessel lumen narrowing and complete obstruction. It was found that plasma ET-1 concentrations were higher in patients with visual ischemic complications. Additionally, an association was found between endothelin expression in temporal artery biopsies at baseline and therapeutic response at month six.
Bosentan has been marketed since 2002 for the management of patients with pulmonary arterial hypertension. This vasodilating drug is an endothelin (ET-1) receptor antagonist.
The investigator hypothesize that a 3-month course of treatment with bosentan, an endothelin receptor antagonist, combined with standard therapy, could be more effective than glucocorticoids (GCs) alone, reducing the risk of relapse and the current adverse effects, thereby improving relapse-free survival at 12 months.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Bosentan + Glucocorticoids | Experimental | Drug: BosentanBosentan : 62.5 mg bid for 4 weeks and 125 mg bid during 9 additional weeks Glucocorticoids : prespecified GC tapering schedule |
| Glucocorticoids | Other | Drug: Glucocorticoidsprespecified GC tapering schedule |
Who may qualify
- Ages
- 50 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (18 listed)
- Patients having given their written informed consent prior to participation in the study
- Patients affiliated with social security or CMU (profit or being entitled)
- Diagnosis of GCA, as defined by the revised GCA diagnosis criteria. Patients must satisfy criteria 1-2-3 and 4 (irrespective of time):
- unequivocal cranial symptoms of GCA (new onset headache, scalp tenderness, jaw claudication, temporal artery abnormality, ischemia-related vision loss)
- unequivocal symptoms of polymyalgia rheumatica (PMR)
Key exclusion criteria (23 listed)
- Patients under maintenance of justice, wardship or legal guardianship
- Patient unable to give written informed consent prior to participation in the study
- Patients included in other investigational therapeutic study within the previous 3 months
- Patients suspected not to be observant to the proposed treatments
- Weight <40 Kg or > 100 Kg
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| BosentanBosentan : 62.5 mg twice a day for 4 weeks and 125 mg twice a day during 9 weeks (treatment length 3 months) | Drug | Bosentan + Glucocorticoids |
| Glucocorticoidsprespecified GC tapering schedule | Drug | Glucocorticoids |
Primary outcome
Failure free survival at Week 52
Time frame: 12 months ( Week 52)
A failure is defined by the occurrence of a relapse or the impossibility to decrease Glucocorticoids according to the predefined scheduled Glucocorticoids scheme.
11 secondary outcomes
Proportion of new ischemic event
Time frame: 12 months (Week 52)
Proportion of patients in remission without prednisone
Time frame: 12 months (Week 52)
Proportion of patients in remission with prednisone ≤5 mg/day
Time frame: 12 months (Week 52)
Cumulative dose of prednisone
Time frame: 12 months (Week 52)
Proportion of patient in remission
Time frame: 2 years
Proportion of patients relapsing
Time frame: year 1 to year 2
Proportion of patients receiving Glucocorticoids
Time frame: 2 years
Quality of life measured by the "Health Assessment Questionnaire" (HAQ)
Time frame: at Week 26 and Week 52
Quality of life measured by the "Short Form 36 Questionnaire" (SF36)
Time frame: at Week 26 and Week 52
Frequency and type of side effects
Time frame: within 1 year after inclusion
Exploratory criteria
Time frame: At the beginning of the study and in both groups at Week 13 and Week 52
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 May 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Luc MOUTHON, Pr study director
Hôpital Cochin, Department of Internal Medicine - 75014, Paris
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Bosentan and Glucocorticoids in people with Giant Cell Arteritis (GCA), run by Assistance Publique - Hôpitaux de Paris at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 18 inclusion and 23 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 6 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Alexis REGENT, Pr (01 58 41 14 55 ext. +33, alexis.regent@aphp.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Failure free survival at Week 52 (time frame: 12 months ( Week 52)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 May 2026.