Lorcaserin is our most advanced investigational drug candidate and is intended for weight management. After completing two Phase 3 clinical trials, BLOOM and BLOSSOM, we submitted a New Drug Application, or NDA, to the FDA in December 2009. In October 2010, the FDA issued a Complete Response Letter, or CRL, regarding the lorcaserin NDA. In the CRL, the FDA stated that it completed its review of the NDA and determined that it could not approve the application in its present form. The FDA outlined reasons for its decision and provided recommendations for addressing the issues it identified in the CRL. We and Eisai are engaged in activities intended to address the issues raised by the FDA as part of the plan to submit a response to the CRL.

In November 2010, we reported top-line results from our third Phase 3 clinical trial for lorcaserin, BLOOM-DM, which evaluated obese and overweight patients with type 2 diabetes. We plan to submit the final study report from the BLOOM-DM trial with our response to the CRL to allow further evaluation of lorcaserin's benefit-risk profile.

Our wholly owned subsidiary, Arena Pharmaceuticals GmbH has granted Eisai Inc. exclusive rights to commercialize lorcaserin in the United States and its territories and possessions subject to FDA approval of the lorcaserin NDA.

About Lorcaserin

Lorcaserin is an investigational drug candidate intended for weight management, including weight loss and maintenance of weight loss, in patients who are obese (BMI ≥30) or patients who are overweight (BMI ≥27) and have at least one weight-related co-morbid condition. Lorcaserin is a new chemical entity that is believed to act as a selective serotonin 2C receptor agonist. The serotonin 2C receptor is expressed in the brain, including the hypothalamus, an area believed to be involved in the control of appetite and metabolism. Arena has patents that cover lorcaserin in the United States and other jurisdictions that in most cases are capable of continuing into 2023 without taking into account any patent term extensions or other exclusivity Arena might obtain.

About Weight Management

According to the Centers for Disease Control and Prevention, approximately one-third of US adults were obese in 2007-2008. Studies have shown that a weight loss of 5% to 10% of body weight from baseline can result in meaningful improvements in cardiovascular risk factors (e.g., lipids, blood pressure and blood glucose) and a significant reduction in the incidence of type 2 diabetes. There are currently limited pharmaceutical treatment options to help patients lose weight.

Our drug candidates have not been approved by the U.S. Food and Drug Administration or any international regulatory agency.