Comparison of Sequential to Initial Combination Therapy in PAH

This study is comparing two different treatment approaches for pulmonary arterial hypertension (PAH) — a serious condition where blood pressure in the lungs is dangerously high — to find out whether starting with a combination of drugs from the beginning works better than adding drugs one at a time. **You may be eligible if...** - You are between 18 and 80 years old and weigh at least 40 kg - You have been diagnosed with PAH (idiopathic, hereditary, or related to conditions like scleroderma, lupus, congenital heart disease, or HIV) - Your heart and lung function fall within categories I–III on the WHO scale (mild to moderately limited) - You have not yet started or are newly starting PAH treatment **You may NOT be eligible if...** - Your PAH is caused by conditions like left heart disease, lung disease, or chronic blood clots in the lungs - You have very severe heart or liver problems - You have had a lung transplant - You are pregnant or breastfeeding - You are currently on medications that interfere with the study drugs Talk to your doctor to see if this trial is right for you.