RO 25-1553

RO 25-1553 is a **synthetic cyclic peptide analog of vasoactive intestinal peptide (VIP)** that was designed to overcome the deficiencies of natural VIP. It is a **potent and selective VIPR2 (VPAC2) receptor agonist** with significantly enhanced potency and stability compared to native VIP. The compound demonstrates **24 to 89 times greater potency than VIP** as a smooth muscle relaxant in guinea pig trachea and shows **390-fold enhancement** over native VIP in human bronchial smooth muscle relaxation. RO 25-1553 exhibits **high selectivity for the VIP2 receptor subclass** and demonstrates **bronchodilatory, anti-inflammatory, and vasodilatory properties**. It was developed by **Hoffmann-La Roche** as a potential therapeutic for respiratory conditions including **COPD and asthma**, with the advantage of being deliverable via inhalation to minimize systemic side effects.