Nintedanib in Progressive Fibrosing Interstitial Lung Disease (PFILD): Assessing Renal Function Trends and Tolerability

<bold>Introduction:</bold> Nintedanib for PFILD was approved in 2021 in the UK. Despite being metabolized by the liver and excreted via faeces/bile, caution is advised in renal impairment. We aim to assess renal function trend and Nintedanib tolerability in patients with impaired renal function (Creatinine Clearance [CrCl]<60mL/min) compared to preserved renal function (CrCl≥60mL/min). <bold>Methods:</bold> Retrospective data were collected from 59 PFILD patients diagnosed by multidisciplinary consensus at an ILD specialist centre. Of these, 35 had baseline CrCl<60, and 24 had CrCl≥60. CrCl was assessed at baseline until treatment cessation or the latest reading by Feb 2024. <bold>Results:</bold> In the CrCl<60 cohort, 6 patients (17%) discontinued Nintedanib due to adverse effects (AEs), 16 (46%) required dosage reductions, and 5 (14%) experienced treatment interruptions. In the CrCl>60 cohort, 8 patients (33%) discontinued treatment, 7 (29%) required dosage reductions, and 7 (29%) experienced treatment interruptions. However, no statistical significance was found between baseline CrCl and Nintedanib discontinuation or dose reduction (p=0.09, p=0.21 respectively). For those with baseline CrCl<60, CrCl remained stable (mean pre- and post-treatment: 43.3 and 44.7mL/min). Median treatment duration was 9 months (IQR 14). Minimum baseline CrCl was 20, stable after 6 months of treatment (CrCl=21). 5 patients showed >10 mL/min decline in CrCl, 4 of whom had baseline CrCl≥60. <bold>Conclusions:</bold> Our small cohort showed that CrCl did not significantly worsen with Nintedanib for patients with baseline CrCl<60 mL/min. AEs leading to treatment discontinuation or dosage reduction were not associated with renal impairment.