Development of a Long-Acting Interleukin-11 Antagonist for the Treatment of Renal Fibrosis.

Renal fibrosis, a key progression of chronic kidney disease (CKD), remains a major challenge in nephrology, with no FDA-approved drugs specifically targeting this condition. Interleukin-11 (IL-11) has emerged as a potential therapeutic target for renal fibrosis. In this study, we identified the antifibrotic effects of a recombinant human IL-11 analogue, IL-11-6M, in a mouse model of unilateral ureteral obstruction (UUO). We generated additional IL-11-6M variants via an optimized Escherichia coli expression system, with one variant (D46C) exhibiting comparable efficacy. Further modified through cysteine-specific PEGylation, analogue 13 demonstrated similar potency to IL-11-6M with an IC50 value of 61.5 ± 26.2 nM and maintained strong binding affinity to IL-11Rα (KD = 3.0 nM). Notably, analogue 13 exhibited a prolonged half-life and showed significant therapeutic effects in the UUO-induced renal fibrosis model. These findings suggest analogue 13 should be a promising candidate for the treatment of renal fibrosis.