Pfizer (NYSE:PFE) plans to spend almost $7 billion to acquire Arena Pharmaceuticals (NSDQ:ARNA). The purchase would bolster its pipeline of immuno-inflammatory drugs. 

ARNA shares surged 80% to $90.08 after the announcement. PFE shares ticked up to $55.20 to 4.57%. 

The transaction was valued at $100 per Arena share in cash. 

The proposal has won the unanimous approval of the boards of directors at both firms. 

Arena’s lead candidate etrasimod, an oral selective sphingosine 1-phosphate (S1P) receptor modulator, offers promise for several immuno-inflammatory diseases, including Crohn’s disease, atopic dermatitis and ulcerative colitis. Arena also has ongoing Phase 2 trials involving etrasimod in eosinophilic esophagitis and alopecia areata.

Earlier this year, Bristol Myers Squibb won the first gastrointestinal indication of an S1P receptor modulator. Known as ozanimod, the drug was branded as Zeopsia. 

Etrasimod has been the subject of 27 clinical studies to date. 

Other drug candidates in Arena’s pipeline include temanogrel and APD418. Temanogrel is a potential for microvascular obstruction and Raynaud’s phenomenon secondary to systemic sclerosis. APD418 is now in a Phase 2 study for acute heart failure.

Arena is also developing a cannabinoid type-2 receptor known as olorinab for the potential treatment of chronic pain, including visceral pain stemming from gastrointestinal disorders.