GSK Answers FDA’s Questions About Horizant

GlaxoSmithKline and XenoPort Inc. Nov. 5 announced that the Food and Drug Administration has accepted for review GSK’s answer to FDA’s complete response letter for Horizant (gabapentin enacarbil) extended-release tablets.

Horizant is under review for the treatment of moderate-to-severe primary restless legs syndrome. In February, FDA issued a complete response letter for Horizant, which said the drug could not be approved because of pre-clinical findings of tumors in rats (8 PLIR 253, 2/26/10).

GSK’s response includes new data from nonclinical studies of Horizant and two epidemiology studies exploring gabapentin use and cancer, the companies said. FDA has designated ...