XenoPort, Glaxo Pain Drug Fails In Midstage Study

NEW YORK (AP) — GlaxoSmithKline and XenoPort Inc. said Monday their developing pain drug failed in a midstage study, citing a high patient response to placebo.

The companies are developing GSK1838262, or XP13512, as a treatment for diabetic peripheral neuropathy, or pain associated with diabetes. They compared the drug candidate with a placebo, and cited a high placebo response rate as a potential reason for the failure.

The 14-week study involved 421 patients with either Type 1 or Type 2 diabetes. Santa Clara, Calif.-based Xenoport and U.K.-based Glaxo said they will evaluate the results to determine the next step for the drug candidate.

In premarket trading, shares of XenoPort lost $3.98, or 23 percent, to $13.40 while GlaxoSmithKline shares gained $1.34, or 4.6 percent, to $30.68.