Interferon gamma-1b as therapy for idiopathic pulmonary fibrosis. An intrapatient analysis

The only proven therapeutic option for idiopathic pulmonary fibrosis (IPF) is lung transplantation. It is biologically plausible that interferon gamma-1b (G-IFN) may halt or even reverse the disease process and therefore prove to be an effective medical therapy. We report our results using this medication in a cohort of patients with a wide range of severity of IPF.

To determine the impact of G-IFN therapy on the progression of disease in patients with IPF.

We performed a retrospective analysis of patients' pulmonary function tests (PFTs), specifically the forced vital capacity (FVC) and the single breath diffusing capacity for carbon dioxide (DLCO). Comparisons of these parameters prior to and after the implementation of therapy were made by generating regression slopes by least-squares equations.

Twenty-two patients qualified for the analysis. For the FVC, comparison of pre- and post-therapy best-fit regression lines demonstrated a significant difference in favor of G-IFN (p<0.015). For the DLCO, a significant difference in favor of gamma interferon therapy was detected in the advanced group (p<0.03). Seventy percent of the patients showed either stabilization or regression of disease in both their FVCs and their DLCO.

G-IFN appears to be an effective new therapy for patients with IPF. Salutary effects on the rate of change in the FVC and DLCO were most apparent in patients with advanced disease. With slowing or reversal in loss of lung function, G-IFN may improve longevity and may have utility as a bridge to lung transplantation in those patients who are appropriate candidates.