A Clinical Trial to Compare the Efficacy of Tadalafil in Pulmonary Hypertension and Interstitial Lung Disease

Abstract

Background: To determine the effects of oral tadalafil on respiratory function in patients with interstitial lung disease (ILD), both with and without pulmonary hypertension (PH). Methods: Patients with ILD-PH (WHO classes 2 and 3) were assigned to group A, while patients with ILD without PH were assigned to group B. Participants in both groups received a daily dose of 40 mg oral tadalafil as an add-on therapy to their conventional treatments for a duration of 6 months. The study outcomes included changes in forced vital capacity (FVC), total lung capacity (TLC), diffusion lung capacity for carbon monoxide (DLCO), residual volume (RV), and a 6-minute walk distance (6MWD). Results: Of the 38 patients enrolled, 34 completed the 6-month treatment and were included in the final analysis. The mean age of participants was 50 years. At 6 months, no significant changes were observed in FVC, forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, and DLCO. However, patients receiving tadalafil showed a significant improvement in median (interquartile range [IQR]) TLC after 6 months of treatment (77.1 [70.2-80.1] mL in group A versus 86.2 [86.3 - 93.1] mL in group B, P = 0.002) and in median (IQR) RV (83.1 [79.1 - 85.2] mL in group A versus 90.2 [86.3 - 93.1] mL in group B, P = 0.02). Additionally, no significant differences were noted in pulmonary arterial pressure (PAP) and 6MWD. No serious adverse effects were reported. Conclusions: A 6-month therapy with tadalafil was shown to partially improve respiratory function in patients with ILD, both with and without PH. This treatment demonstrated an acceptable safety profile.