Mereo BioPharma Group plc (Nasdaq: MREO) shares jumped 38.46% to $3.06 in the After-market hours after the joint statement by Ultragenyx Pharmaceutical Inc. (Nasdaq: RARE), and Mereo BioPharma (Nasdaq: MREO) that both companies have signed a patent and partnership arrangement for setrusumab, a monoclonal antibiotic medicinal medicine, Setrusumab is a fully human monoclonal antibody investigational anti-sclerostin that has shown the potential to increase bone production and density, contributing to higher bone strength in OI animal models. Mereo’s Phase2b results on setrusumab show a dose-dependent improvement in bone growth, density, and intensity in adults with OI.
OI is a category of genetic diseases, comprising types I, III, and IV, of which roughly 85-90% are caused by defects in the genes COL1A1 or COL1A2, resulting in either decreased levels of natural collagen or abnormally shaped collagen and improvements in the metabolism of the bone. These anomalies contribute to increased bone resorption, decreased bone density, bone fragility, and weakening since collagen molecules constitute the base from which bone is created. While defective or insufficient collagen weakens the bone, these collagen defects often cause a maladaptive cascade of bone remodeling signals that boost bone resorption or bone breakdown, with inadequate development of the new bone that compounds bone fragility. These genetic abnormalities and their effects contribute to systemic clinical symptoms such as reduced bone mass, bone fragility higher than normal fracture rates, including atypical sites, or deformities of the bone, including irregular curvature of the spine discomfort, decreased mobility, and short stature. In the developing world, OI affects nearly 60,000 patients and has no approved therapies.
Setrusumab is a totally human sclerostin-inhibiting monoclonal antibody, a protein that operates on a central bone-signaling pathway and inhibits bone-forming cell development. The anti-sclerostin antibody induces new bone growth, increased collagen production, and enhanced bone mineral density and strength by blocking the inhibitory action of sclerostin. Inhibition of sclerostin also decreases unnecessary resorption of bone, further increasing the effect on bone density. Usage of anti-sclerostin antibodies has been shown to promote bone growth, boost bone mass and density, decrease bone fragility, increase long bone stiffness and strength, and decrease the number of fractures in various mouse models of OI. Overall, bone mass and strength gains were improved when an anti-sclerostin antibody, the current norm of treatment in OI, was used in conjunction with bisphosphonates.