NEW YORK, January 23, 2013 /PRNewswire/ -- The European Medicines Agency, the continent's equivalent of the US's Food and Drug Administration, is voicing out concerns about Arena Pharmaceuticals, Inc.'s (NASDAQ:ARNA) [ Full Research Report]  weight loss pill, Belviq due to alleged side effects like tumors and psychiatric events. Consequently, stock fell as much as 11 percent to fall below $9 per share. The company has to prove the European agency and the Committee for Medicinal Products for Human Use - who discovered the side effects - that the slight variations in those side effects are relative to placebo and means nothing compared to the benefit of the drug. With this, Arena is expecting a final decision on EU approval in the first half of 2013. However, a report from Motley Fool is showing optimism on the company's part, believing that the price reduction after the early January 2013 surge could help bring it back above the $10 range. This is due to the stock price recently breaking out of the $8-$9.50 range it stayed for more than six months last year. In addition, Arena has sparked the interest of hedge funds, with some recently buying stocks in bulk. Roughly 29 million shares have been acquired by hedge funds in the previous quarter, led by Wellington Capital. Their movements were instrumental in the previous price bump. Meanwhile, another biopharmaceutical firm Amgen, Inc. (NASDAQ:AMGN) [ Free Research Report]  has seen its stock price and revenues increase to $83.29 and $4.32 billion, respectively, but has been downgraded to "neutral" from "outperform" by Zacks. The target price was also lowered to $86 from $100. The investment research firm says they are concerned about Amgen's dependence on Prolia/Xgeva for long-term growth, which are some of the company's several key products expected to lose patent protection in the following years.