Treprostinil (Tyvaso) is currently approved for the treatment of pulmonary arterial hypertension (PAH; WHO Group 1) to improve exercise ability. If approved, it will be the first and only therapeutic approved for treatment of interstitial lung disease (PH-ILD). The sNDA is supported by data from the multicenter, double-blind, placebo-controlled phase III INCREASE study that assessed the efficacy and safety of treprostinil inhalation solution in 326 adult patients with ILD. Patients were randomized 1:1 to receive either inhaled treprostinil 0.6mg/mL four times daily or placebo for 16 weeks.
The primary endpoint was the change in 6-minute walk distance (6MWD) at peak exposure from baseline to Week 16. As announced in a press release on February 24, 2020, the INCREASE study met its primary endpoint as treprostinil boosted 6MWD by 21 meters versus placebo (P = .0043, Hodges-Lehmann estimate) after 16 weeks of treatment. In addition, the treatment variance in 6MWD at Week 16 was statistically considerable when examined using mixed model repeated measurement (31 meters; P <.001).
Benefits of treprostinil were noted across several key subgroups, including etiology of PH-ILD, disease severity, age, gender, dose, and baseline hemodynamics. Moreover, patients treated with treprostinil attained substantial enhancements in all secondary endpoints, including decrease in the cardiac biomarker NT-proBNP, time to first clinical exacerbation event, change in peak 6MWD at Week 12, and change in trough 6MWD at Week 15. Treatment linked with treprostinil was revealed to be well tolerated. The safety profile of treprostinil was consistent with that observed in prior studies in pulmonary arterial HTN and with known prostacyclin-related adverse events.
In the press release, Martine Rothblatt, PhD, chairman and CEO of United Therapeutics, stated, “Tyvaso, if approved by the FDA, would be the first and only therapeutic approved for the treatment of PH-ILD, a condition that afflicts approximately 30,000 people in the United States. We look forward to working with the Agency during the regulatory review process, with the goal of expanding the population of patients with pulmonary hypertension who could benefit from this important medicine.”
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