A $2.5 billion biotech takeover

Ra Pharmaceuticals is getting gobbled at an impressive premium: Belgium-based UCB Pharma will acquire the rare disease biotech for $2.5 billion, or $48 a share — more than double its closing price earlier this week. 

The acquisition will give UCB access to a drug called zilucoplan, which is being tested in Phase 3 for myasthenia gravis — a rare autoimmune disease that causes a weakening of the skeletal muscles. Some preliminary data have suggested that Ra’s drug could prove to be steep competition against Alexion’s Soliris, which is approved for myasthenia gravis as well. 

Jefferies analysts project blockbuster sales for zilucoplan — with U.S. sales topping out around $630 million, and worldwide sales exceeding $1 billion.