Pfizer to Acquire Arena Pharmaceuticals for $6.7 Billion, Arena Shares Surge Over 80%

On December 13, Pfizer announced that it had reached a definitive agreement with Arena to acquire all of the latter's outstanding shares for $100 per share in an all-cash transaction, with a total value of approximately $6.7 billion. The boards of both companies unanimously approved this transaction. As of the closing, Arena's stock price surged over 80%.

Arena Pharmaceuticals' pipeline products mainly focus on gastrointestinal diseases, skin diseases, and heart disease. This includes etrasimod, an oral selective sphingosine 1-phosphate (S1P) receptor modulator being developed for the treatment of a range of immune-inflammatory conditions, including gastrointestinal and dermatological diseases.

Etrasimod is currently undergoing two Phase III studies for ulcerative colitis, one Phase II/III study for Crohn's disease, one Phase III study for atopic dermatitis, and Phase II studies for eosinophilic esophagitis and alopecia areata. On December 5, 2017, Everest Medicines obtained the exclusive rights for the development and commercialization of etrasimod and ralinepag in Greater China from Arena Pharmaceuticals for an upfront payment of $12 million and milestone payments of $212 million.

Arena's pipeline also includes two cardiovascular drugs in Phase II: temanogrel and APD418. Temanogrel is being developed for the treatment of secondary microvascular obstruction and Raynaud's syndrome in systemic sclerosis, while APD418 is being developed for the treatment of acute heart failure.