UCB, a Belgium-based biopharmaceutical firm, has agreed to acquire Ra Pharmaceuticals, a United States-based clinical-stage biopharmaceutical company, it was reported on Friday.

The deal is valued at around USD2.1bn. According to the contract, Ra Pharmaceuticals shareholders will receive USD48 in cash for each share at closing.

Ra Pharma utilises an advanced peptide chemistry platform for the production of novel therapeutics to treat serious diseases caused by excessive or uncontrolled activation of the complement system. Ra Pharma's ExtremeDiversity platform facilitates the production of synthetic macrocyclic peptides through merging the diversity and specificity of antibodies with the pharmacological properties of small molecules. The company's phase 3 product candidate, Zilucoplan is a once-daily self-administered, subcutaneous peptide inhibitor of C5. It is being evaluated in phase 3 for the treatment of myasthenia gravis, an unpredictable and chronic auto-immune condition, in which auto-antibodies infect specific proteins in the neuro-muscular junction.