Arena and Eisai Expand Pact for Lorcaserin

Arena Pharmaceuticals, Inc.

and Eisai Inc. announced today the expansion of the lorcaserin marketing and supply agreement between Arena Pharmaceuticals, Inc.'s wholly owned subsidiary, Arena Pharmaceuticals GmbH, and Eisai Inc. Lorcaserin is an investigational drug candidate intended for weight management. In addition to the United States, the territories in the expanded agreement now include most of North and South America, including Canada, Mexico and Brazil. This expansion builds on the agreement executed by Eisai and Arena in July 2010 for Eisai's exclusive rights to market and distribute lorcaserin in the United States, subject to lorcaserin's approval by the US Food and Drug Administration (FDA).