As part of the deal, UCB will manufacture and supply the product for commercialisation and Daiichi will manage the distribution and book sales.
The deal, which is subject to achievement of certain milestones in the future, will see Daiichi Sankyo pay UCB about €180m of upfront and milestones payments during the coming years.
UCB CEO-elect Jean-Christophe Tellier said: "We continue executing on our partnering strategy for Japan to enhance patient access to our core medicines in concert with strong and patient-focused partners.
"We share our partner’s passion for people living with epilepsy and for Lacosamide, and believe that Daiichi Sankyo’s excellence and overall market presence, including specialist areas addressing epilepsy such as neurology, neurosurgery and psychiatry, will enhance and broaden patients’ access to new treatment options for epilepsy in Japan."
At present, lacosamide is not approved in Japan for the treatment of epilepsy.
In October, UCB reported positive results from a Phase III trial evaluating Lacosamide as adjunctive therapy in the treatment of Japanese and Chinese adult patients with partial-onset seizures.
The trial met its primary efficacy endpoint and showed that compared to placebo, Lacosamide 200mg/day and 400mg/day significantly reduced partial-onset seizure frequency.
Based on these results, UCB intends to submit regulatory applications in Japan and China in 2015 for Lacosamide as adjunctive therapy to treat adults with partial-onset seizures.