The safety and tolerability of inhaled treprostinil in patients with pulmonary hypertension and chronic obstructive pulmonary disease

The primary aim was to explore the safety and tolerability of inhaled treprostinil when used in patients with pulmonary hypertension (PH) with concomitant chronic obstructive pulmonary disease (COPD). Patients with a diagnosis of pre-capillary PH (defined as pulmonary artery mean pressure of ≥ 25 mmHg and pulmonary artery wedge pressure or left ventricular end diastolic pressure of ≤ 15 mmHg) who were being initiated on inhaled treprostinil and had concomitant COPD (defined as FEV1/FVC ratio ≤ 70% with FEV1 ≥ 40% predicted) were considered for inclusion in this pilot study. Assessments included adverse events, physical exam, World Health Organization (WHO) functional class, 6-minute walk test (6MWT), modified Borg dyspnea score, and concomitant medication. At baseline and week 16 St. George's Respiratory Questionnaire (SGRQ), arterial blood gas (ABG), and pulmonary function test (PFT) were assessed. The median age was 65 years (age range, 56-80 years) and five patients (56%) were men. Among the nine patients, a majority had an increase in 6MWT from baseline to week 16 (median change, 19 m). Only three of the nine patients (33%) had an increase in A-a gradient at week 16 (median change, -7). There was no difference in any of the following: arterial blood gases, WHO functional class, 6MWT results, or SGRQ scores from baseline to week 16. There was a statistically significant decline in several of the PFT measures, including FEV1 (median change, -0.18 L; P = 0.004; median change, -7% of predicted; P = 0.016), FVC (median change, -0.23 L; P = 0.027), and diffusion capacity for carbon monoxide (DLCO) (median change, -5% of predicted; P = 0.023). The small number of patients limits firm conclusions; however, inhaled treprostinil did not seem to adversely impact oxygenation in the majority of the study patients with pre-capillary PH and COPD. While there may have an adverse impact on some pulmonary function parameters, the clinical significance is unclear.