Discovery of Sulfonyl Hydrazone Derivative As a New Selective PDE4A and PDE4D Inhibitor by Lead-optimization Approach on the Prototype LASSBio-448: In vitro and In vivo Preclinical Studies

Phosphodiesterase 4 (PDE4) inhibitors have emerged as a new strategy to treat asthma and other lung inflammatory diseases. Searching for new PDE4 inhibitors, we previously reported the discover of LASSBio-448, a sulfonamide with potential to prevent and reverse pivotal pathological features of asthma. In this paper, two novel series of sulfonamide (6a-6m) and sulfonyl hydrazone (7a-7j) analogues of LASSBio-448 have been synthetized and evaluated for selective inhibitory activity toward cAMP-specific PDE4 isoforms. From these studies, we have identified 7j (LASSBio-1632) as a new anti-asthmatic lead-candidate associated with selective inhibition of PDE4A and PDE4D isoenzymes and blockade of airway hyper-reactivity (AHR) and TNF-α production in the lung tissue. In addition, it was able to relax guinea pig trachea on non-sensitized and sensitized animals and showed great TGI permeability.