Pfizer Acquires Arena Pharmaceuticals for $6.7 Billion

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Pfizer’s $6.7 billion acquisition of Arena will give them access to a portfolio of immuno-inflammatory therapies.

Pfizer announced on Dec. 13, 2021 that it had entered into a definitive agreement to acquire Arena Pharmaceuticals, a clinical stage company specializing in therapies treating immuno-inflammatory diseases, for $6.7 billion dollars. The acquisition gives Pfizer access to Arena’s diverse drug portfolio, most notably etrasimod, a drug candidate for the treatment of immune-mediated and inflammatory disease.

Etrasimod is an oral, selective sphingosine 1-phosphate (SIP) receptor modulator that is currently in development for a range of immuno-inflammatory diseases, including gastrointestinal and dermatological diseases. According to a company press release, a recent Phase II study on the effects of etrasimod on ulcerative colitis demonstrated that most patients who achieved clinical response, clinical remission, or endoscopic improvement at week 12 experienced sustained or improved effects up to week 46 with etrasimod.

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

“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 and general manager, Pfizer Inflammation and Immunology, in a company release. “Utilizing Pfizer’s leading research and global development capabilities, we plan to accelerate the clinical development of etrasimod for patients with immuno-inflammatory diseases.”


“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 CEO, Arena, in the press release. “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.”

Source: Pfizer