Long-term efficacy of inhaled N-acetylcysteine in patients with idiopathic pulmonary fibrosis

BACKGROUND

Inhalation of N-acetylcysteine (NAC) has been carried out in our department since 1994 for treating interstitial pneumonia such as idiopathic pulmonary fibrosis (IPF). In this study, the clinical efficacy and safety of long-term NAC inhalation monotherapy for IPF was investigated.

METHODS

NAC inhalation was carried out in 23 of 34 cases diagnosed as IPF by surgical lung biopsy in our department between 1994 and 2008. The treatment was continued for one year or longer in 14 cases. In these 14 cases and in 11 cases without treatment, the clinical courses, prognosis, lung function (%FVC, %DLco, and %TLC), and changes in serum markers for interstitial pneumonia (KL-6 and SP-D) were examined.

RESULTS

There were no significant differences in survival curves between the two groups. Acute exacerbation was observed in 4 of 14 cases (28.6%) receiving NAC inhalation. Compared with the results just before the beginning of NAC inhalation, Δ%FVC and Δ%DLco in the treated cases were -4.7% and -2.9% one year later and -4.0% and -5.8% two years later, respectively. In cases without treatment, Δ%FVC and Δ%DLco were -3.5% and +5.3% one year later and +0.2% and +1.0% two years later, respectively.

CONCLUSION

Since this study is an open case-control study in a single institute and the number of cases is not large, its use in evaluating the efficacy of NAC inhalation monotherapy is limited. In addition, the role of NAC inhalation in combination with a steroid, an immunosuppressive agent, and a new anti-fibrosis drug should also be investigated.

Recent advances in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) remains the most common of the idiopathic interstitial pneumonias and portends a poor prognosis. Significant strides have been made in the approach to diagnosis and in the ability to predict outcome in the last few years. Advances in high-resolution CT (HRCT) scanning have allowed an accurate diagnosis obviating the need for surgical biopsy in many patients. Furthermore, HRCT scanning may aid in determining prognosis and identifying disease progression. The appropriate use of the HRCT scan requires a multidisciplinary iterative approach incorporating all available data to reach a final diagnosis. However, there remains great heterogeneity in disease progression. Pulmonary hypertension and acute exacerbations of IPF negatively influence prognosis and are increasingly a target of therapy. There has been an increase in the number of well-designed clinical trials of IPF that have focused on more specific targets. While no cure has yet been found, each trial expands our understanding regarding the natural course of the disease and the impact of targeted therapy. In the interim, lung transplantation, which appears to improve survival in a subset of IPF patients, remains the only intervention. The objective of this article is to review advances in the understanding of IPF and the evidence for the findings outlined above.

Clinical review: Idiopathic pulmonary fibrosis—Past, present and future

Idiopathic pulmonary fibrosis (IPF) is an important, and devastating, interstitial lung disease. It has a median mortality of only 3 years, worse than many cancers, and its incidence continues to rise. In this article, an overview of key developments in our understanding and clinical management of IPF will be provided.

Idiopathic pulmonary fibrosis : new concepts in pathogenesis and implications for drug therapy

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and usually fatal pulmonary disease for which there are no proven drug therapies. Anti-inflammatory and immunosuppressive agents have been largely ineffective. The precise relationship of IPF to other idiopathic interstitial pneumonias (IIPs) is not known, despite the observation that different histopathologic patterns of IIP may coexist in the same patient. We propose that these different histopathologic 'reaction' patterns may be determined by complex interactions between host and environmental factors that alter the local alveolar milieu. Recent paradigms in IPF pathogenesis have focused on dysregulated epithelial-mesenchymal interactions, an imbalance in T(H)1/T(H)2 cytokine profile and potential roles for aberrant angiogenesis. In this review, we discuss these evolving concepts in disease pathogenesis and emerging therapies designed to target pro-fibrogenic pathways in IPF.