United Therapeutics Corporation (NASDAQ: UTHR) announced that its TETON-1 phase 3 study of nebulized Tyvaso for idiopathic pulmonary fibrosis met its primary endpoint and was published in The New England Journal of Medicine.

The study demonstrated that nebulized Tyvaso preserved lung function as measured by absolute forced vital capacity and reduced the risk of clinical worsening events with statistical significance. The median change in FVC at week 52 was -43.3 mL in the Tyvaso group compared to -196.2 mL in the placebo group, representing a between-group difference of 130.1 mL.

Nebulized Tyvaso reduced the risk of clinical worsening events by 33% relative to placebo. Combined analyses of TETON-1 and TETON-2 studies showed the treatment achieved statistically significant effects across the primary endpoint and most secondary endpoints.

The TETON-1 study enrolled 598 patients with IPF in the United States and Canada over 52 weeks. Results were presented at the American Thoracic Society International Conference.

United Therapeutics plans to submit a supplemental New Drug Application to the FDA by the end of summer to add IPF to Tyvaso's labeled indications. The FDA has granted orphan designation for treprostinil to treat IPF.

Nebulized Tyvaso is currently approved for pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease. The use of nebulized Tyvaso for IPF remains investigational and has not been approved by the FDA.