Amsulostat CAS# 2409963-83-1

PXS-5505 is a potent pan-lysyl oxidase (LOX/LOXL1-4) inhibitor with low-micromolar IC₅₀s that selectively blocks cross-linking activity without hitting other amine oxidases. In vitro, it irreversibly inhibits LOX family activity and reduces collagen crosslinking and stromal remodeling in 3D organotypic matrices, suppressing cancer-associated fibroblast-driven matrix stiffening and invasion without directly affecting cell proliferation at high concentrations. In multiple rodent models, oral PXS-5505 decreases fibrosis—reducing dermal thickness and α-smooth muscle actin in systemic sclerosis models and normalizing lung/organ fibrosis markers—and in pancreatic cancer KPC and PDX models it reduces collagen deposition, tumor stiffness, improves perfusion, lowers metastasis and enhances gemcitabine efficacy, extending median survival by ~35–45% versus chemo alone at ~20 mg/kg dosing. These animal data support robust in vivo target engagement and antifibrotic/antistromal effects.