XenoPort, Inc. (NASDAQ: XNPT) And GlaxoSmithKline (NYSE: GSK) Declines After FDA’s Response Letter

XenoPort, Inc. (NASDAQ: XNPT) and GlaxoSmithKline (NYSE: GSK) reported yesterday that they have received a Complete Response letter from the U.S. Food and Drug Administration regarding the New Drug Application for Horizant™ Extended-Release Tablets, an investigational non-dopaminergic treatment for moderate-to-severe primary Restless Legs Syndrome.

As a result, XenoPort, Inc. (NASDAQ: XNPT) plunged 64.03% to $7.05 in the pre-market session. XenoPort closed at $19.60 in the last trading session. In the last six months, XNPT has gained over 2%.

GlaxoSmithKline plc (ADR) (NYSE: GSK) declined 1.14% to $38.91 in the pre-market session. GSK closed at $39.36 in the last trading session.