Initiation of BPS-804 Phase 2b study

Mereo BioPharma Group plc

("Mereo" or the "Company" or the "Group")

Initiation of BPS-804 potentially pivotal Phase 2b study in patients with osteogenesis imperfecta, an orphan disease

 Headline data expected mid-2018

London, 4 May 2017 - Mereo BioPharma Group plc (AIM: MPH), a clinical stage, UK-based, biopharmaceutical company focused on rare and specialty diseases, announced today the initiation of the potentially pivotal Phase 2b clinical study of BPS-804 for the treatment of the orphan disease, osteogenesis imperfecta (OI) (brittle bone disease), the ASTEROID study. BPS-804 has been granted Orphan Drug Designation by the US FDA and the EMA. BPS-804 has also been accepted into the EMA's Adaptive Pathways Programme.

Dr Denise Scots-Knight, Chief Executive Officer of Mereo BioPharma Group plc commented:

"The initiation of this potentially pivotal trial is an important milestone in the development of BPS-804. Osteogenesis imperfecta is a serious, debilitating and painful disease for which there are currently no approved treatments that address the underlying bone weakness. 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 the top-line results for the ASTEROID study, which we expect in mid-2018."

OI is a rare genetic disorder that is characterized by fragile bones that break easily. Current treatment of OI patients is largely surgical and focuses on reducing pain or addressing the complications associated with this disorder. BPS-804 is a fully humanised monoclonal antibody targeting sclerostin, a protein which itself prevents the activity of bone-forming cells. Treatment with BPS-804 increases bone formation and reduces bone resorption, thereby strengthening the bone and potentially reducing fractures in OI patients.

Clinical studies in 83 patients to date have shown that BPS-804 is safe and well tolerated. In a study in OI patients BPS-804 showed a statistically significant improvement in bone mineral density and on bone biomarkers.

Details of the study

The Phase 2b trial is expected to enrol up to 120 adult OI patients and is a randomised, double-blind, placebo-controlled, multi-centre study which is being conducted in the US and Europe.

The study's primary endpoint is change in trabecular volumetric bone mineral density measured by high resolution peripheral quantitative CT (HRpQCT) and change in bone strength on finite element analysis (FEA). Additional endpoints include further measures of bone parameters on HRpQCT, bone turnover markers and quality of life scores.

Mereo intends to begin a further study in paediatric OI patients in H2 2017.

For further information on patient recruitment of this trial, visit: https://clinicaltrials.gov/ NCT identifier: NCT03118570

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About Mereo

Mereo is a UK-based biopharmaceutical company focused on the development of innovative medicines that aim to address unmet medical needs in rare and specialty disease areas and improve patient quality of life. The Company seeks to selectively acquire development-stage product candidates with demonstrated clinically meaningful data from large pharmaceutical companies and to rapidly progress these product candidates to subsequent value inflection points.

Mereo combines the operational discipline and efficiency of a small company with the financial resources to conduct comprehensive clinical studies. The Company has the option to directly commercialise products, for example in orphan diseases, in addition to partnering or divesting its products.

Mereo's initial portfolio consists of three mid-late stage clinical assets that were acquired from Novartis in July 2015. BPS-804 is being developed for the prevention of fractures resulting from osteogenesis imperfecta (brittle bone disease); acumapimod (BCT-197), is being developed to treat inflammation in patients with an AECOPD; and BGS-649 is a once-weekly pill to restore normal testosterone levels in men with hypogonadotropic hypogonadism.

In H1 2016 the Company initiated a Phase 2b study with BGS-649 and a Phase 2 study with acumapimod. 

Mereo initiated the first pivotal Phase 2b trial for BPS-804 (the ASTEROID study) during H1 2017. Additional product opportunities, from a range of large pharmaceutical and biotechnology companies, are under active evaluation.

About osteogenesis imperfecta (OI)

OI is a rare genetic disorder that is characterized by fragile bones that break easily. In addition to fractures, people with OI often have muscle weakness, hearing loss, fatigue, joint laxity, curved bones, scoliosis, and short stature. The majority of cases of OI (estimated at approximately 90 %) are caused by a dominant mutation in a gene coding for type I collagen, a key component of healthy bone. Current treatment of OI is supportive, focusing on minimizing fractures and maximizing mobility, but to date, there are no EMA or FDA approved treatments.