Intravenous Immunoglobulin for the Treatment of Acute Exacerbations of Idiopathic Pulmonary Fibrosis

Acute exacerbations of idiopathic pulmonary fibrosis (AE-IPF) are sudden, life-threatening deteriorations associated with high mortality. Despite their severe impact on a substantial subset of patients with IPF, no treatment has yet demonstrated clear, reproducible benefit, and standardized therapeutic strategies remain lacking. This prospective, multicenter, randomized study aims to address this critical unmet need by evaluating the efficacy of IVIG in patients with AE-IPF. Aberrant inflammation and dysregulated immune responses are believed to play a key role in the pathogenesis of AE-IPF. Patients with IPF often display impaired cellular and humoral immunity, further supporting the investigation of immunomodulatory therapies. Intravenous immunoglobulin (IVIG), which has established anti-inflammatory and immunomodulatory effects, is used in other rapidly progressive interstitial lung diseases and in various immune-mediated conditions. Preliminary retrospective data from investigators' center suggest that IVIG may improve gas exchange and survival in patients hospitalized with acute exacerbations of fibrotic interstitial lung disease, including IPF. Investigators hypothesize that the addition of IVIG to usual treatment may improve clinically relevant outcomes during AE-IPF. In this study, IVIG will be administered as an adjunct to usual care. Usual care will include pulse corticosteroids, broad-spectrum antibiotics, prophylactic anticoagulation, and oxygen therapy. Although the effectiveness of corticosteroids in AE-IPF remains uncertain and is supported only by low-quality evidence, their use is endorsed by current treatment guidelines and remains widespread in clinical practice. In addition, corticosteroids are being evaluated in ongoing trials (e.g., EXAFIP2, NCT05674994). Considering the complex, multi-pathway biology of AE-IPF and the documented synergistic effects of IVIG and corticosteroids in other immune-mediated conditions (such as Kawasaki disease, idiopathic thrombocytopenic purpura, and toxic epidermal necrolysis/Stevens-Johnson syndrome), corticosteroids will be administered to both study arms to avoid withholding a potentially beneficial therapy. The primary objective of this clinical trial is to evaluate whether IVIG, when added to usual care, improves outcomes compared to usual care alone in patients hospitalized with AE-IPF. The primary endpoint is a composite of all-cause in-hospital mortality or the need for endotracheal intubation. This composite measure was selected because AE-IPF is a rapidly progressive and life-threatening event, and these outcomes represent the most objective, clinically meaningful indicators of deterioration. The use of this endpoint enables a comprehensive assessment of treatment efficacy by capturing both fatal and near-fatal clinical events. Investigators anticipate that the findings of this study will generate important evidence regarding the potential role of IVIG in the management of AE-IPF and may contribute to future treatment recommendations for this highly lethal condition.