Abstract Rationale Increased interleukin (IL)-11 levels have been observed in patients with idiopathic pulmonary fibrosis compared with healthy subjects. The aim of this study was to evaluate IL-11 levels as a potential prognostic marker in progressive pulmonary fibrosis (PPF) in serum samples from the INBUILD trial in 228 patients with PPF who received placebo for ≥52 weeks (W). Methods Free IL-11 (fIL-11) serum levels were analysed using a sandwich immunoassay at W12 (baseline), W24, W36 and W52. The assay was clinically validated retrospectively using the fit-for-purpose principle, including the determination of several parameters (e.g., precision and selectivity). Regression models assessed associations between fIL-11 levels at W12 and measures of disease progression at W52 and over the whole trial by quantile-based cut-offs (Q1, median, Q3). Results In placebo-treated patients, fIL-11 increased from 0.337±0.203ng/L (W12) to 0.411±0.266ng/L (W52). Dichotomised analyses showed an association with differences in relative decline in forced vital capacity (FVC) 10% predicted from W12-52 (all cut-off levels), but not with rate of decline in FVC (mL/year). All cut-offs were also associated with differences in time to first acute exacerbation or death (W12 to trial end). Cutting data at median or Q3, fIL-11 levels were associated with differences in time to death and time to first occurrence of any composite endpoint component, namely first acute ILD exacerbation or first non-elective hospitalisation for respiratory cause or death. Conclusions This is the first study showing that fIL-11 serum levels may have prognostic potential in patients with PPF. A prospective trial is needed to confirm these findings. This abstract is funded by: Boehringer Ingelheim
Wollin et al. (Fri,) studied this question.