GSW001

GSW001 is a bone-targeted, pH-sensitive prodrug conjugate consisting of a bisphosphonate derivative linked to a peptide aldehyde inhibitor of Cathepsin K (CTSK) [1073]. Developed by researchers at the University of Michigan and Mayo Clinic, GSW001 is designed to selectively inhibit bone degradation by osteoclasts without reducing new bone formation, thereby avoiding the cardiovascular toxicities associated with systemic small-molecule Cathepsin K inhibitors [1073]. The conjugate remains inactive at physiological pH but undergoes pH-responsive cleavage and activation below pH 5.2, specifically within the acidic resorption lacuna of osteoclasts [1073]. In preclinical murine models of ovariectomy-induced osteoporosis, biweekly administration of GSW001 significantly increased bone volume fraction (BV/TV) in the femur and L4 vertebrae without reducing osteoclast numbers [1073].