 Shares of Pfizer Inc. PFE, 2.32 were up 2.0 in trading on Friday after the company said it closed its 6.7 billion acquisition of Arena Pharmaceuticals Inc. Arena is developing treatments for immuno-inflammatory diseases like ulcerative colitis and atopic dermatitis. It has said it expects to share data from a Phase 3 clinical trial testing one of those experimental therapies, etrasimod, in ulcerative colitis patients during the first quarter of his year. 