Objective Progressive pulmonary fibrosis (PPF) is a chronic interstitial lung disease (ILD) characterized by fibrotic progression and poor prognosis, with effective treatment strategies for previously untreated patients remaining unclear. This study evaluated the efficacy and safety of upfront combination therapy with anti-inflammatory and antifibrotic agents in previously untreated PPF patients. Methods This multicenter, single-arm phase 2 study enrolled 34 patients with ILD—including unclassifiable idiopathic interstitial pneumonia, idiopathic nonspecific interstitial pneumonia, fibrotic hypersensitivity pneumonitis, and rheumatoid arthritis–associated ILD—all with evidence of PPF. Tacrolimus (0.0375 mg·kg −1 twice daily) and prednisolone (10 mg once daily) were initiated on day 1, with nintedanib (150 mg twice daily) added on day 8. The tacrolimus dosage was adjusted to maintain blood trough levels. The primary endpoint was the change in the relative decline slope for forced vital capacity % predicted (%FVC) between before and after treatment. Results The protocol treatment was associated with a substantial improvement in the relative %FVC decline slope, from −20.9%/year before to +11.2%/year after treatment. Subgroup analysis revealed greater improvement in patients with an increased lymphocyte percentage in bronchoalveolar lavage fluid or elevated blood biomarkers. Adverse events, such as diarrhea (67.6%) and hepatic dysfunction (29.4%), were manageable, with no severe cases or treatment discontinuations. Conclusion Early combination therapy with tacrolimus, prednisolone, and nintedanib was associated with improved pulmonary function and was well tolerated in previously untreated PPF patients. Our findings suggest the potential of this regimen as an initial treatment strategy, but further validation in larger randomized controlled trials is warranted.
Tsubouchi et al. (Thu,) studied this question.