GlaxoSmithKline (GSK) and XenoPort inked a deal related to XP13512, a prodrug of gabapentin that improves its bioavailability. XP13512 is currently in Phase III for restless legs syndrome (RLS) and in Phase II for neuropathic pain.
The exclusive co-development and commercialization agreement pertains to the U.S. and other countries worldwide, excluding certain Asian countries. XenoPort is entitled to receive $75 million upfront in cash. It is also eligible to aggregate milestones of up to $65 million for development activities leading up to the NDA filing for RLS, up to $210 million in other potential development and regulatory payments, and up to $290 million in potential sales milestones based on successful commercialization for RLS and neuropathic pain.
In addition to royalties on sales outside the U.S., XenoPort is entitled to receive tiered double-digit royalty payments on U.S. sales. If it elects to co-promote XP13512 with GSK in the U.S., however, it will be entitled to participate in a net profit share in the U.S.
In the U.S., XenoPort will complete the ongoing studies to support RLS development. Subject to positive Phase III data, GSK will file the NDA. GSK will lead development and registration of XP13512 for all other indications, including neuropathic pain. GSK will also be solely responsible for its manufacture to support its development and commercialization within the licensed territories.