Limited efficacy of nintedanib for idiopathic pleuroparenchymal fibroelastosis.

Background: The antifibrotic agent nintedanib has been reported to effectively prevent the decline in forced vital capacity (FVC) in a broad range of interstitial lung diseases. However, the efficacy of nintedanib against idiopathic pleuroparenchymal fibroelastosis (iPPFE) remains unclear.

Methods: We retrospectively examined patients with idiopathic PPFE or idiopathic pulmonary fibrosis (IPF) who received nintedanib for more than 6 months. We evaluated annual changes in %FVC, radiological PPFE lesions, and body weight before and during nintedanib treatment. To investigate radiological PPFE lesions, we examined the fibrosis score, which was defined as the mean percentage of the high attenuation area in the whole lung parenchyma using three axial computed tomography images.

Results: Overall, 15 patients with iPPFE and 27 patients with IPF were included in the present study. In patients with IPF, the annual rate of decline in %FVC was significantly lower during nintedanib treatment than that before treatment (-2.01%/year [-7.64 to 3.21] versus -7.64%/year [-10.8 to -4.44], p = 0.031). Meanwhile, in patients with iPPFE, the annual rate of decline in %FVC during nintedanib treatment was higher than that before treatment (-18.0%/year [-21.6 to -12.7] versus -9.40%/year [-12.3 to -8.23], p = 0.109). In addition, nintedanib treatment failed to inhibit the annual rate of increase in fibrosis score in patients with iPPFE (6.53/year [1.18-15.3] during treatment versus 2.70/year [0.27-12.2] before treatment, p = 0.175).

Conclusions: Nintedanib efficacy may be limited in patients with iPPFE.