Table 1. Efficacy parameters tested in historical registration trials of drugs approved for use in pulmonary arterial hypertension
DrugStudy acronymParameters that improved[Ref.]
Exercise capacityFCHaemodynamicsTTCWSigns and symptomsSurvival
Endothelin pathway
    BosentanStudy 351 BREATHE-1↑↑↑↑↑NT[4, 5]
    Sitaxsentan#STRIDE-1 and 2↑↑↑↓↓NT[6, 7]
    AmbrisentanARIES-1 and 2↑↑↑↑↑NT[8]
NO pathway
    SildenafilSUPER-1↑↑↑↓↓NT[9]
    TadalafilPHIRST↑↓↑↑↓NT[10]
Prostacyclin pathway
    Intravenous epoprostenol↑↑↑NTNT↑[11, 12]
    Inhaled iloprostAIR↑↑↑↑↑NT[13]
    Subcutaneous treprostinil↑NT↑↑↑NT[14]
    Inhaled treprostinilTRIUMPH↑↓NT↓↓NT[15]
    Oral beraprostALPHABET↑↑↓↑↑NT[16, 17]

  • FC: functional class; TTCW: time to clinical worsening; NO: nitric oxide; NT: not tested; ↑: parameter improved; ↓: parameter did not improve. #: withdrawn from market in 2010 due to two cases of fatal hepatic failure linked to its use; : TTCW was defined as a combination of ≥10% improvement in walking distance combined with an absence of clinical deterioration.