Highlights of weekly biotech stock moves

Arena Pharmaceuticals Inc. (NASDAQ:ARNA) jumped $2.54 (29%) to $11.39 on Wednesday after FDA approved an NDA for Belviq lorcaserin for chronic weight management. The approval triggered a $20 million milestone payment from marketing partner Eisai Co. Ltd. (Tokyo:4523; Osaka:4523). But the gains didn't last long; for the week, Arena was up $0.10 to $9.98(see B10).

Fellow obesity companies Orexigen Therapeutics Inc. (NASDAQ:OREX) and Vivus Inc. (NASDAQ:VVUS) also rose on the news. Orexigen gained $1.47 (36%) to $5.54 on the week, while Vivus was up $2.03 to $28.54. The latter has a July 17 PDUFA date for its Qnexa phentermine/topiramate...