A Randomized, Double-Blind, Placebo-Controlled Study of Pulsed, Inhaled Nitric Oxide in Subjects at Risk of Pulmonary Hypertension Associated With Pulmonary Fibrosis

Background: The interstitial lung diseases include a variety of disorders, many of which are characterized by fibrotic changes (fILD). Of the fILDs, Idiopathic pulmonary fibrosis is the most common. Pulmonary hypertension (PH) frequently complicates fILD and is associated with impaired functional capability, lower physical activity, and significantly reduced life expectancy. There is no proven treatment for patients with fILD-PH. We report results from the first cohort of a phase 2b/3 trial with pulsed inhaled nitric oxide (iNO) in patients with fILD-PH. Methods: Subjects in cohort 1 were randomized to iNO 30 μg/kg ideal body weight/h (iNO30) or placebo for 8 weeks of blinded treatment; subjects then transitioned to open-label extension (OLE) on iNO30 followed by dose escalation to iNO45 then iNO75. Activity monitoring was used to assess changes in daily activity. Safety and efficacy were evaluated. Results: Twenty-three patients were randomized to iNO30 and 18 to placebo. During blinded treatment, iNO30 subjects showed an average improvement in moderate/vigorous physical activity (MVPA) and remained stable in overall activity. Placebo subjects showed an average drop of 26% in MVPA and a 12% drop in overall activity. The iNO group had an improvement in oxygen saturation. During OLE, subjects maintained their activity levels including placebo subjects who transitioned from a decline to a maintenance in all activity parameters. Inhaled nitric oxide at all doses (30, 45, and 75) was safe and well tolerated. Conclusions: Treatment with iNO30 demonstrated clinically and statistically significant benefit in MVPA and clinically significant benefit in overall activity. In the OLE, higher doses of iNO were also safe and well tolerated while showing maintenance in activity parameters.