Mereo BioPharma Group PLC is a United Kingdom (U.K.) based biopharmaceutical company focused on the development of therapeutics for rare diseases. The company has developed a portfolio of late-stage clinical product candidates, and its two rare disease product candidates are setrusumab for the treatment of osteogenesis imperfecta (OI) and alvelestat primarily for the treatment of severe alpha-1 antitrypsin deficiency-associated lung disease (AATD-LD).