UPDATE 1-XenoPort, Arena shares fall on discounted stock offer

* XenoPort's 2.5 mln shr offering priced at $19/shr

* Arena's 12.5 mln shr offering priced at $4.17/shr

* XenoPort, Arena shares down more than 11 pct

July 8 (Reuters) - Shares of U.S. drugmakers XenoPort Inc (XNPT.O) and Arena Pharmaceuticals Inc (ARNA.O) fell more than 11 percent on Wednesday, after their public offering of shares was priced below their Tuesday close.

XenoPort, a biopharmaceutical company that is developing drugs for migraine headaches, neuropathic pain and restless leg syndrome among others, said it is offering 2.5 million common shares at $19 a share.

XenoPort shares closed at $21.50 Tuesday on Nasdaq. They fell to $18.87 in Wednesday morning trade.

Arena, which is seeking U.S. regulatory approval for its experimental obesity drug Lorcaserin, said it is offering 12.5 million common shares at $4.17 apiece. It expects gross proceeds of about $52.1 million.

Shares of Arena fell to $4.08 in morning trade Wednesday. They closed at $4.67 Tuesday on Nasdaq.

For the alerts, please click [ID:nWNAB5291] [ID:nWNAB5295] (Reporting by Esha Dey in Bangalore; Editing by Ratul Ray Chaudhuri)