TETON is a Phase 3 program consisting of two Phase 3 studies of Tyvaso® in subjects with idiopathic pulmonary fibrosis (IPF). The first of these studies, TETON 1, is enrolling patients in the United States. The second of these studies, TETON 2, is in start-up mode and will enroll patients outside the United States. In both cases, the primary endpoint is the change from baseline to week 52 in absolute forced vital capacity (FVC). Both the FDA and the European Medicines Agency have granted orphan designation for treprostinil to treat IPF.
These programs were prompted by data from the INCREASE study, which demonstrated improvements in parameters of lung function in pulmonary hypertension patients with fibrotic lung disease, including absolute FVC, and reduced exacerbations of underlying lung disease. Specifically, in the INCREASE study, treatment with inhaled treprostinil resulted in significant improvements in percent predicted FVC at Weeks 8 and 16, with subjects having underlying etiologies of IIP (Week 8: 1.95%, p=0.0373 and Week 16: 2.88%; p=0.0096) and idiopathic pulmonary fibrosis (Week 8: 2.543%; p=0.0380 and Week 16: 3.504%; p=0.0147) showing greater improvement. Consistent positive effects were also observed in patients with CHP and environmental/occupational lung disease. These data points, combined with substantial preclinical evidence of antifibrotic activity of treprostinil, suggest that Tyvaso may offer a treatment option for patients with fibrotic lung disease.