Abstract
Idiopathic pulmonary fibrosis (IPF) is a form of idiopathic interstitial pneumonia characterized by temporally and spatially heterogeneous fibroblast proliferation and poor prognosis. No therapies have been shown in randomized clinical trials (RCT) to influence survival. Twenty-nine subjects were assigned randomly in a pilot study to a double-blind, placebo-controlled, RCT to test sildenafil in patients with IPF with forced vital capacity 40–90% and diffusing capacity 30–90% of predicted. During the 6-month experimental treatment period, patients underwent 6-min walk tests and estimation of dyspnea using the Borg scale at baseline (0 months), 3 months, and 6 months. Participants had moderate impairment of pulmonary function, and there were no significant differences between placebo (n = 15) and sildenafil (n = 14)-treated groups. Sildenafil did not significantly increase 6-min walk test distance (mean distance ± SD after 6-month protocol: placebo 355 ± 82 m, sildenafil 324 ± 41 m; p = 0.256) nor did it lessen dyspnea after exercise (mean Borg score after 6-month protocol: placebo 3.4 ± 1.6, sildenafil 4.1 ± 2.3; p = 0.492). Adverse reactions were few and minor in nature. In this trial, sildenafil did not significantly increase 6-min walk test distance or decrease the Borg dyspnea index in patients with clinically typical IPF. This trial was registered at clinicaltrials.gov as NCT00359736.
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Acknowledgments
The authors thank Ghazwan Butrous, MD, PhD, and Toni Miles for facilitating the donation of sildenafil and placebo tablets by Pfizer UK, and Evelyn Guadalupe, R.Ph., Chhavi Gupta, and Rolando Garcia-Rojas for technical assistance. This work was supported by the VA Research Service. Dr. Butrous is a shareholder in and received monthly salary support from Pfizer. No other author has any actual or apparent conflict of interest.
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Supported by a Merit Review grant from the VA Research Service.
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Jackson, R.M., Glassberg, M.K., Ramos, C.F. et al. Sildenafil Therapy and Exercise Tolerance in Idiopathic Pulmonary Fibrosis. Lung 188, 115–123 (2010). https://doi.org/10.1007/s00408-009-9209-8
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DOI: https://doi.org/10.1007/s00408-009-9209-8