United Therapeutics Corporation (NASDAQ: UTHR) today announced that preliminary analysis indicates that the INCREASE clinical study of Tyvaso® (treprostinil) Inhalation Solution in patients suffering from World Health Organization (WHO) Group 3 pulmonary hypertension associated with interstitial lung disease (PH-ILD) has met its primary efficacy endpoint of demonstrating improvement in six-minute walk distance (6MWD).

Tyvaso increased six-minute walk distance by 21 meters versus placebo (p=0.0043, Hodges-Lehmann estimate) after 16 weeks of treatment. Benefits of Tyvaso were observed across several key subgroups, including etiology of PH-ILD, disease severity, age, gender, baseline hemodynamics, and dose.

Significant improvements were also observed in each of the study's secondary endpoints including reduction in the cardiac biomarker NT-proBNP, time to first clinical worsening event, change in peak 6MWD at Week 12, and change in trough 6MWD at week 15. Treatment with Tyvaso of up to 12 breaths per session, four times daily, in the INCREASE study was well tolerated and the safety profile was consistent with previous Tyvaso studies in PAH and known prostacyclin-related adverse events (see the discussion of adverse events below under "About Tyvaso").

"Patients with both interstitial lung disease and pulmonary hypertension have worse clinical trajectories and earlier death than patients with interstitial lung disease alone. There are currently no approved therapies for these patients and so there is a tremendous unmet need," said Aaron Waxman, M.D., Ph.D., Director of the Pulmonary Vascular Disease Program at Brigham and Women's Hospital and the chair of the INCREASE Study Steering Committee. "This is the largest clinical trial in this population, and the first to demonstrate a clear benefit. As a clinician, I look forward to soon having an approved treatment to offer these patients with this life-threatening disease."

"I am pleased to announce the successful outcome of the INCREASE phase III trial of Tyvaso in a unique kind of pulmonary hypertension, a variant that has no approved therapy," said Martine Rothblatt, Ph.D., Chairman and Chief Executive Officer of United Therapeutics. "Some 30,000 Americans suffer from this disease, called WHO Group 3 Pulmonary Hypertension. It is a tremendous testament to our head of product development, Dr. Leigh Peterson, that her team used the unique characteristics of our inhaled medicine to achieve a highly statistically significant proof of efficacy while seeming to avoid the safety issues that have plagued systemic therapeutics."

"The results of the INCREASE study present a powerful message of efficacy in the interstitial lung disease patient population," said Gil Golden, M.D., Ph.D., Chief Medical Officer of United Therapeutics. "I congratulate the patients and families who participated in this study, along with our principal investigators who produced a clear outcome that we think could change the lives of ten times the number of patients who are on Tyvaso today. This is what we mean at United Therapeutics when we say we 'identify the corridors of indifference and run like hell down them.'"

United Therapeutics plans to submit the results to the U.S. Food and Drug Administration by mid-year in support of an efficacy supplement that is expected to result in revised labeling that reflects the outcome of the INCREASE study.