A bad year for XenoPort (XNPT) just got substantially worse. The Santa Clara, CA-based developer says that its lead program--which is partnered with GlaxoSmithKline--flunked a Phase IIb trial for migraines, apparently scuttled by a high placebo effect. And XenoPort's already battered share price plunged more than 25 percent as investors digested the fresh round of sour reports.
GSK1838262/XP13512, also known as Horizant, failed to perform significantly better than a placebo among the 526 patients recruited for the migraine study. "XenoPort is disappointed by these study results, especially the high placebo response rate, which may have impacted the ability of the trial to detect the potential benefit of GSK1838262 in patients with migraine headaches," said CEO Ronald W. Barrett. None of the actual data was released today.
Back in 2007 GSK paid XenoPort $75 million upfront and promised $275 million in development and regulatory milestones along with $290 million in sales milestones, plus royalties, to gain licensing rights for the drug as a treatment for restless leg syndrome as well as migraines. Earlier this year, though, the FDA rejected their RLS application, leery of its risk/benefit profile.
The FDA raised a red flag over a possible cancer link raised in animal studies, a serious threat for patient not facing a life threatening condition. XenoPort responded by slashing its workforce in half and narrowing its focus.