Researchers in Shanghai described a circular RNA (circRNA) encoding human relaxin‑2 (cRLN2) as a protein‑replacement therapeutic for liver fibrosis. The circRNA approach leverages inherent stability and low immunogenicity to produce sustained therapeutic protein expression, showing antifibrotic activity in preclinical models. The team reported amelioration of fibrotic markers and improved liver histology after cRLN2 administration, positioning circRNA as an alternative to mRNA or protein therapies for chronic tissue disorders. The paper highlights formulation, dosing durability and tissue targeting as key development challenges. Biotech developers should note circRNA’s potential to reduce dosing frequency and evade innate immune triggers, but translational risk remains in scalable manufacture, delivery to fibrotic tissue and long‑term safety readouts.