In a move that may concern those responsible for payment of healthcare costs, Pfizer and Arena Pharmaceuticals, Inc. announced that the companies have entered into a definitive agreement under which Pfizer will acquire Arena, a clinical stage company developing innovative potential therapies for the treatment of several immuno-inflammatory diseases.

Under the terms of the agreement, Pfizer will acquire all the outstanding shares of Arena for $100 per share in an all-cash transaction for a total equity value of approximately $6.7 billion. The boards of directors of both companies have unanimously approved the transaction.

Pfizer expects to finance the transaction with existing cash on hand.

“The proposed acquisition of Arena complements our capabilities and expertise in Inflammation and Immunology, a Pfizer innovation engine developing potential therapies for patients with debilitating immuno-inflammatory diseases with a need for more effective treatment options,” said Mike Gladstone, Global President & General Manager, Pfizer Inflammation and Immunology. “Utilizing Pfizer’s leading research and global development capabilities, we plan to accelerate the clinical development of etrasimod for patients with immuno-inflammatory diseases.”

Arena’s portfolio includes diverse and promising development-stage therapeutic candidates in gastroenterology, dermatology, and cardiology, including etrasimod, an oral, selective sphingosine 1-phosphate (S1P) receptor modulator currently in development for a range of immuno-inflammatory diseases including gastrointestinal and dermatological diseases.

Arena has built a robust development program for etrasimod, including two Phase 3 studies in ulcerative colitis (UC), a Phase 2/3 program in Crohn’s Disease, a planned Phase 3 program in atopic dermatitis, and ongoing Phase 2 studies in eosinophilic esophagitis and alopecia areata.

In addition, Arena’s pipeline includes two development-stage cardiovascular assets, temanogrel and APD418. Temanogrel is currently in Phase 2 for the treatment of microvascular obstruction and Raynaud’s phenomenon secondary to systemic sclerosis. APD418 is currently in Phase 2 for acute heart failure.

“We’re delighted to announce Pfizer’s proposed acquisition of Arena, recognizing Arena’s potentially best in class S1P molecule and our contribution to addressing unmet needs in immune-mediated inflammatory diseases,” said Amit D. Munshi, President and Chief Executive Officer of Arena. “Pfizer’s capabilities will accelerate our mission to deliver our important medicines to patients. We believe this transaction represents the best next step for both patients and shareholders.”

Under the terms of the merger agreement, Pfizer will acquire all of the outstanding shares of Arena common stock for $100 per share in cash. The proposed transaction is subject to customary closing conditions, including receipt of regulatory approvals and approval by Arena’s stockholders.