Idiopathic Pulmonary Fibrosis: New Concept of Pathogenesis and Treatment

Article information

J Korean Med Assoc. 2009;52(1):22-29
Publication date (electronic) : 2009 January 10
doi : https://doi.org/10.5124/jkma.2009.52.1.22
Department of Respiratory and Allergy Medicine, Soonchunhyang University College of Medicine E – mail: uhstuhst@paran.com

Abstract

Abstract

Idiopathic pulmonary fibrosis (IPF) is characterized by chronic progressive parenchymal lung fibrosis. Although extensive researches for IPF pathogenesis have been reported for several decades, the precise mechanisms are still unknown and the specific treatments for elimination of fibrosis and prolongation of survival are also still unknown. The role of inflammation as initial insult of lung fibrosis is still debating by controversial results of animal model experiments. The recent proposed mechanism for IPF is a dysregulation of epithelial-mesenchymal interactions which have critical role in tissue repair process and fibrosis. This hypothesis suggests impaired communications between epithelium and mesenchymal cells in terms of abnormal proliferation of mesenchymal cells instead of normal proliferation of epithelium. At recent, epithelial mesenchymal transition is regarded as an important source of myofiborblast which are major cells producing extracellular matrix. Classical treatment agents including steroid are already known to be ineffective in treatment of IPF, and also, IFN- one of newly emerging drug, is proved to be ineffective in treatment of IPF. Now new drugs involved in the molecular levels of signal transduction of fibrotic pathway, inhibition of various growth factors (TGF, CTGF, VEGF), and direct inhibition of fibrotic cytokines are under investigated in animal experiments and human clinical studies. Further studies should be focused on the evaluation of precipitating factors, genetic markers, drugs for inhibiting specific molecules responsible for lung fibrosis, and agents for controlling ECM precipitation.

Figure 1.

Schematic pathway of lung fibrosis and therapeutic agents (dotted line).

Ongoing clinical trials in therapeutic agents for IPF (www.Clinicaltrials.gov)

Completed clinical trials in therapeutic agents for IPF (www.Clinicaltrials.gov)

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Article information Continued

Figure 1.

Schematic pathway of lung fibrosis and therapeutic agents (dotted line).

Table 1.

Ongoing clinical trials in therapeutic agents for IPF (www.Clinicaltrials.gov)

Trial Phase Patient numbers Design Endpoints
Antibody for MCP-1 II 120 Randomized, double-blind, placebo-controlled Efficacy
Pirfenidone III 750 Open label, uncontrolled Adverse events or death
Ambrisentan (ARTEMIS) III 600 Randomized, double-blind, placebo-controlled Death or disease progression
Bosentan (BUILD3) III 600 Open-label Long term safety and tolerability
PDL, AZA, NAC* (PANTHER) III 390 Randomized, double-blind, placebo-controlled PDL+AZA+NAC, NAC alone, placebo Change of FVC
Pirfenidone II 090 Open label, uncontrolled Adverse events
Sildenafil (STEP-IPF) III 170 Randomized, double-blind, placebo-controlled 6-min walk distance
Sildenafil IV 050 Randomized, double-blind, placebo-controlled 6-min walk distance
Pirfenidone III 400 Randomized, double-blind, placebo-controlled Change of FVC
Bosentan IV 050 Randomized, open-label 6-min walk distance
Angiokinase inhibitor II 400 Randomized, double-blind, placebo-controlled Change of FVC
Zileuton II 140 Randomized, open-label LTB4 in BAL flluid
*

PDL: prednisone, AZA: azathioprine, NAC: N-acetyl cysteine

Table 2.

Completed clinical trials in therapeutic agents for IPF (www.Clinicaltrials.gov)

Trial Phase Patient numbers Primary endpoints Results
Thaliomide II 119 Safety, feasibility and efficacy, Not reported
Imatinib mesylate II/III 120 Progression (FVC change), Not reported
NAC* (INFIGENIA) III 184 VC and DLCO Favor results
Bosentan (BUILD-1) II/III 158 6-min walk distance, No significant effect
Etanercept II 188 Safety and efficacy, No significant effect
Aerosol IFN I/II 115 Safety and efficacy, Not reported
*

PDL: prednisone, AZA: azathioprine, NAC: N-acetyl cysteine