Arena Pharmaceuticals Announces First Quarter 2009 Financi...(mon stock to Azimuth at a pre-negotiated...)

• Received net proceeds of $14.6 million as reimbursement for improvements made to one of Arena's facilities.

• Announced the completion of a positive randomized, double-blind, placebo-controlled Phase 1 program and the initiation of a Phase 2 clinical trial of a second generation oral niacin receptor agonist intended for the treatment of atherosclerosis in Arena's partnership with Merck.

Scheduled Earnings Call

Arena will host both a conference call and webcast to discuss the first quarter 2009 financial results and to provide a business and financial update today, Monday, May 11, 2009, at 5:00 p.m. Eastern Time (2:00 p.m. Pacific Time). Jack Lief, President and Chief Executive Officer and Robert E. Hoffman, Vice President, Finance and Chief Financial Officer will host the conference call.

The conference call may be accessed by dialing 877.857.6151 for domestic callers and 719.325.4806 for international callers. Please specify to the operator that you would like to join the "Arena Pharmaceuticals First Quarter 2009 Earnings Call." The conference call will be webcast live under the investor relations section of Arena's website at www.arenapharm.com, and will be archived there for 30 days following the call. Please connect to Arena's website several minutes prior to the start of the broadcast to ensure adequate time for any software download that may be necessary.

Upcoming Corporate Presentations

Arena is planning to present at upcoming investment and industry conferences, including:

• The 34th Annual Deutsche Bank Health Care Confer
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