Effects of nintedanib in patients with progressive fibrosing ILDs and differing baseline FVC: further analyses of the INBUILD trial

Background: In the INBUILD trial, nintedanib slowed the rate of decline in FVC over 52 weeks vs placebo in subjects with non-IPF progressive fibrosing ILDs. Subjects were required to have an FVC ≥45% predicted at baseline. Aim: To assess the effect of nintedanib on FVC decline in subjects with differing FVC at baseline in the INBUILD trial. Methods: The rate of decline in FVC (mL/year) over 52 weeks was assessed in subgroups by FVC % predicted at baseline (≤50%, >50%–≤70%, >70% predicted). Results: At baseline, in subjects with FVC ≤50% predicted (n=75), >50%–≤70% predicted (n=314) and >70% predicted (n=274), mean (SD) FVC was 1673 (374) mL, 2073 (511) mL and 2806 (739) mL, respectively. In the placebo group, the mean (SE) rate of decline in FVC over 52 weeks was numerically greater in subjects with FVC ≤50% predicted at baseline than in the other subgroups (Figure). The effect of nintedanib vs placebo on reducing the rate of decline in FVC was numerically more pronounced in subjects with FVC >70% predicted at baseline, but the treatment-by-subgroup-by-time interaction p-value did not indicate a differential treatment effect of nintedanib across the subgroups by FVC % predicted (p=0.75). Conclusion: Nintedanib slows the rate of FVC decline in subjects with progressive fibrosing ILDs, irrespective of their degree of FVC impairment at baseline.