Celgene ($CELG) is trading $7.2 billion in cash for Receptos ($RCPT) and its Phase III autoimmune treatment, building on some recent success in the field.

Under the deal, Celgene has agreed to pay $232 per share of the San Diego-headquartered company, a nearly 18% premium to its closing price on Monday. In exchange, the Big Biotech gets ozanimod, formerly RPC1063, which is a promising oral treatment now in Phase III development for ulcerative colitis and multiple sclerosis. If all goes according to plan, the drug could bring in peak annual sales of as much as $6 billion, Celgene figures.