Mereo BioPharma completes patient enrollment for BPS-804 Phase 2b trial in osteogenesis imperfecta

British specialty biopharma company Mereo BioPharma Group has completed patient enrollment for a Phase 2b clinical trial of its human monoclonal antibody BPS-804, also known as Setrusumab. This trial aims to evaluate BPS-804 as a potential treatment for osteogenesis imperfecta (OI), commonly referred to as brittle bone disease.

Osteogenesis imperfecta is a rare genetic disorder characterized by fragile bones that break easily. BPS-804 has received Orphan Drug Designation from both the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA). Additionally, in February 2017, the EMA’s Adaptive Pathways Program accepted BPS-804 and granted it PRIority MEdicines (PRIME) designation.

Mereo BioPharma Group has indicated that BPS-804 works by inhibiting the sclerostin protein, which normally blocks the activity of bone-forming cells. The company believes this mechanism could be beneficial in treating osteogenesis imperfecta, potentially offering a novel approach that could reduce fracture risks and improve patient quality of life.

Phase 2b Trial: ASTEROID

The Phase 2b trial, named ASTEROID, is set to be conducted across the United States and Europe. It will involve 112 adults with osteogenesis imperfecta, who will be randomized into four groups. Among these groups, one will be an open-label arm. The trial will collect six-month data on the top dose of BPS-804, with results expected in the first half of next year. Additionally, 12-month data is anticipated to be released in the second half of 2019.

The primary endpoint of the ASTEROID trial is the change in Bone Mineral Density (BMD) from baseline after 12 months, as measured by High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT). Secondary endpoints include BMD measurements using conventional two-dimensional Dual-Energy X-ray Absorptiometry (DXA) and serum bone biomarkers.

Expert Commentary

Alastair Mackinnon, Chief Medical Officer of Mereo BioPharma Group, commented, “This is another important milestone in the development of BPS-804 for Osteogenesis Imperfecta, which is a serious, debilitating, and painful orphan disease for which there are currently no EMA or FDA approved treatments. We believe BPS-804’s mechanism of action is specifically suited to OI and has the potential to become a novel treatment option that could reduce fractures and improve the quality of life of these patients. We look forward to announcing data from this study during the course of 2019.”