Abstract

Despite antifibrotic treatments being available there is still an unmet medical need for new effective and well-tolerated treatments for idiopathic pulmonary fibrosis (IPF). The ongoing Phase 2 AIR trial is a multi-centre, open-label, single-arm, 36-week trial investigating the safety, efficacy, and pharmacokinetics of the angiotensin II type 2 receptor (AT2R) agonist C21, administered at a dose of 100 mg twice daily, in subjects with IPF.
An interim analysis was performed on the first 21 evaluable subjects enrolled. All subjects were anti-fibrotic-naïve and mean baseline forced vital capacity (FVC) was 71.3% predicted (SD 10.3). UIP was confirmed, by central reader, on historic CT scans; spirometry was centralised with best test review. Normalised change per 24 weeks in FVC was summarised by visit including 90% two-sided CI for the mean, assuming normality, with imputation of missing data, assuming an untreated decline of 60 mL/12 weeks.
FVC change (with imputation for missing data) was -14 mL/24 weeks (90% CI -191, 163) at 24 weeks (n=21) and +84 mL/24 weeks (90% CI -80, 248) at 36 weeks (n=21). For cases with complete data, FVC increased by +251 mL/24 weeks (90% CI -140, 641) at 24 weeks (n=9) and by +497 mL/24 weeks (90% CI 135, 860) at 36 weeks (n=7).
C21 was well tolerated with no treatment-related serious adverse events and no signals of gastro-intestinal toxicity.
In conclusion, these interim results suggest that C21 potentially improves lung function in individuals with IPF not previously treated with anti-fibrotic therapy.