French pharma giant Sanofi said Monday it will buy US group Principia Biopharma for $3.68 billion in a deal that will boost its research and development into autoimmune and allergic diseases. The deal will see Sanofi "acquire all of the outstanding shares of Principia for $100 per share in cash, which represents an aggregate equity value of approximately $3.68 billion", Sanofi said in a statement. sbo/as/nth/wdb/rma