Structure-Based Discovery of Potent and Selective Small-Molecule α5β1 Integrin Inhibitors for Asthma Therapy

Integrin α5β1 is the principal fibronectin-binding integrin in airway smooth muscle (ASM), and its modulation attenuates airway narrowing induced by asthmagenic cytokines in mouse models of allergic asthma. These findings highlight small molecule α5β1 inhibition as a promising therapeutic strategy. Although inhalation is the preferred route for asthma therapy, previously reported α5β1 antagonists lacked sufficient potency, selectivity, or inhalation pharmacokinetic data. Here, we report a potent series of α5β1 inhibitors identified through structure-based design and sequential optimization. Lead compound <b>65</b> demonstrates subnanomolar cellular potency, high selectivity over other integrins, and favorable rodent pharmacokinetics following inhalation dosing. These attributes support its potential as a once-daily inhaled therapy for asthma. Collectively, our results establish selective α5β1 inhibition by inhalation as a novel approach to reduce ASM tension through the disruption of cellular tethering.