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The Impact of ERA Switching on Risk Stratification in Pulmonary Arterial Hypertension
Sponsor: University of Sao Paulo General Hospital
Summary
Pulmonary arterial hypertension (PAH) is a rare, progressive, and potentially life-threatening disease characterized by pulmonary vascular remodeling, increased pulmonary vascular resistance, and right ventricular dysfunction. The endothelin pathway plays a central role in its pathophysiology and is targeted by endothelin receptor antagonists (ERAs), including ambrisentan and bosentan. Ambrisentan is a selective ETA receptor antagonist, whereas bosentan blocks both ETA and ETB receptors. Although transitions between ERAs occur in clinical practice, evidence regarding the clinical impact of switching from ambrisentan to bosentan remains limited. ACTION is a retrospective, observational, single-center cohort study evaluating adult patients with pulmonary arterial hypertension (World Health Organization Group 1) and/or chronic thromboembolic pulmonary hypertension (World Health Organization Group 4) confirmed by right heart catheterization. Patients who switched from ambrisentan to bosentan because of a national ambrisentan shortage will be compared with clinically similar patients who remained on ambrisentan. Clinical, functional, and laboratory data recorded at baseline and at 3 to 6 months of follow-up will be assessed. The primary outcome is the proportion of patients with worsening risk stratification after switching from ambrisentan to bosentan compared with patients who continued ambrisentan. Risk will be evaluated using the COMPERA 2.0 and REVEAL Lite 2 assessment tools. Secondary outcomes include changes in World Health Organization/New York Heart Association functional class, 6-minute walk distance, BNP levels, individual risk-assessment components, hepatic enzymes, hemoglobin levels, and clinically relevant events such as hospitalization, emergency department visits, initiation of supplemental oxygen, and right heart failure decompensation.
Official title: ACTION - The Impact of ERA Switching on Risk Stratification in Pulmonary Arterial Hypertension
Key Details
Gender
All
Age Range
18 Years - Any
Study Type
OBSERVATIONAL
Enrollment
183
Start Date
2025-08-20
Completion Date
2026-12-01
Last Updated
2026-07-06
Healthy Volunteers
No
Conditions
Interventions
Switch from Ambrisentan to Bosentan
This intervention refers to a therapeutic switch from ambrisentan (10 mg once daily) to bosentan (125 mg twice daily) in adult patients with pulmonary arterial hypertension (PAH), performed as part of routine clinical care. The switch was not assigned by the investigators but was made based on clinical indications prior to study enrollment. Patients are followed prospectively for up to 6 months to assess changes in risk stratification, functional status, laboratory parameters, and safety outcomes.
Maintenance of Ambrisentan Therapy
Continued treatment with ambrisentan 10 mg once daily without transition to bosentan, as part of routine clinical care. Treatment was not assigned by the investigators. Clinical, functional, laboratory, and safety outcomes are assessed over a 3- to 6-month period.
Locations (1)
InCor - FMUSP
São Paulo, São Paulo, Brazil