Board Change

Mereo BioPharma Group plc

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

Board Change-Non-Executive Director

London, 11 February 2019 - Mereo BioPharma Group plc (AIM: MPH), a clinical stage, UK-based, biopharmaceutical company focused on rare and specialty diseases, announces that Dr. Frank Armstrong has informed the Board of his decision to step down as a non-executive director of the Company, with immediate effect in order to focus on his other board and portfolio positions.

As part of Mereo's proposed combination with OncoMed Pharmaceuticals announced on 5 December 2018, following completion and subject to the usual regulatory due diligence, current OncoMed directors Michael Wyzga and Dr Deepa Pakianathan will be appointed as independent non-executive directors to Mereo. Michael Wyzga is currently the President of MSW Consulting Inc. and was formerly President and Chief Executive Officer of Radius Health, Inc. Prior to that he served in various senior management positions at Genzyme Corporation, including as Chief Financial Officer. Dr Deepa Pakianathan is a Managing Member at Delphi Ventures and serves on the board of directors of Alder Biopharmaceuticals, Inc., Karyopharm Therapeutics, Inc., and Calithera Biosciences, Inc.

Dr. Peter Fellner, Chairman of the Board of Directors said:

"On behalf of the Board, I would like to thank Frank for his commitment to Mereo, having served as a founding board director since the Company's formation in 2015. He has remained an important counsel as Mereo has grown and delivered significant operational success. I, along with rest of the Board, wish him well with his future endeavours".

About Mereo

Mereo is a biopharmaceutical company focused on the development and commercialisation of innovative therapeutics that aim to improve outcomes for patients with rare diseases. Mereo's strategy is to selectively acquire product candidates that have already received significant investment from pharmaceutical companies and that have substantial preclinical, clinical and manufacturing data packages. Each of Mereo's four product candidates has previously generated positive clinical data for Mereo's target indication or in a related indication. Since inception Mereo has commenced large, randomised, placebo-controlled Phase 2 clinical trials for all four of the product candidates:

· BPS-804 for osteogenesis imperfecta (OI). The Company recently announced completion of enrolment with 112 adult patients in a Phase 2b dose ranging study with some initial data expected in the H1 2019 and top-line dose ranging data in late 2019. A pediatric Phase 3 study design has also been approved by the EMA. BPS-804 has orphan designation in the US and EU and has been accepted into the PRIME and Adaptive Pathways in EU;

· MPH-966 for alpha-1 antitrypsin deficiency (AATD). The Company recently announced first patient in a Phase 2 dose ranging study in the US with data expected in late 2019;

· BCT-197 for acute exacerbations of COPD (AECOPD). The Company announced positive Phase 2 data in May 2018; and

· BGS-649 for hypogonadotropic hypogonadism (HH). The Company announced positive top-line Phase 2b data in March 2018 and positive results from the Phase 2b safety extension study in December 2018.

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