Mereo BioPharma begins BPS-804 mid-stage trial in osteogenesis imperfecta

British specialty biopharma company Mereo BioPharma Group has wrapped up enrollment of patients for a phase 2b clinical trial that will evaluate its human monoclonal antibody BPS-804 (Setrusumab) as a potential treatment option for osteogenesis imperfecta (OI), better known as the brittle bone disease.

Osteogenesis imperfecta is a rare, chronic genetic disorder that makes bones fragile. BPS-804 had secured Orphan Drug Designation from the US Food and Drug Administration (FDA) and also the European Medicines Agency (EMA).

Further, the EMA’s Adaptive Pathways Program had accepted BPS-804 in February 2017 and had granted it PRIority MEdicines (PRIME) designation.

According to Mereo BioPharma, BPS-804 inhibits the sclerostin protein which blocks the activity of bone-forming cells. The British pharma firm believes that the mechanism of action of the drug could be useful for the treatment of osteogenesis imperfecta and can potentially become a novel treatment that could lower the risk of fractures and enhance patient quality of life.

Alastair Mackinnon – Chief Medical Officer of Mereo BioPharma Group, commenting on the phase 2b trial of BPS-804 in osteogenesis imperfect, said: “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 quality of life of these patients. We look forward to announcing data from this study during the course of 2019.”

BPS-804’s phase 2b trial named as ASTEROID, which will be held in the US and Europe, will feature 112 adults with osteogenesis imperfecta, who will be randomized into four groups.

One of the four patient arms is ASTEROID is an open label-arm. The six-month data from the phase 2b trial on the top dose of BPS-804 is likely to come out in the first half of next year. On the other hand, the 12-month data is slated to be published in the second half of 2019.

Mereo BioPharma said that the top-line 12 month data pertaining to the blinded dose ranging part of the phase 2b trial is likely to be released in Q4 2019.

ASTEROID’s primary endpoint has been defined as change from baseline of Bone Mineral Density (BMD) after 12 months as measured by High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT) and the secondary endpoints of BMD using conventional two-dimensional dual-energy X-ray absorptiometry (DXA) measurement along with measurement of serum bone biomarkers.