Table 6. Endothelin pathway in PAH—summary of clinical studies.
| ERA | Study | Background | Primary endpoint | Secondary endpoints | Duration (weeks) | Patients |
|---|---|---|---|---|---|---|
| Bosentan (Tracleer) | Study 351 | None | 6MWT | TTCW | 12 | 32 |
| BREATHE-1 | None | 44 m (P<0.001) | TTCW | 16 | 213 | |
| BREATHE-2 | None | PVR | – | 12 | 33 | |
| EARLY | PDE5i (16%) | PVR, 6MWD | TTCW | 24 | 185 | |
| BREATHE-5 | None | PVR, SaO2 | – | 12 | 54 | |
| Ambrisentan (Letairis) | ARIES-1 | None | 31 m (5 mg) and 51 m (10 mg) | TTCW (ns) | 12 | 202 |
| ARIES-2 | None | 32 m (2.5 mg) and 59 m (5 mg) | TTCW | 12 | 192 | |
| Macitentan (Opsumit) | SERAPHIN | None/PDE5i/iloprost | TTCW: 46.4% placebo, 38.0% 3 mg, 31.4% 10 mg | Safety | 100 | 742 |
PVR, pulmonary vascular resistance; PDE5, phosphodiesterase-5; PAH, pulmonary arterial hypertension; 6MWD, 6-minute walk distance.