Subjects enrolled in the SP615, SP756, or SP774 open-label extension (OLE) trials receiving oral SPM 927 for at least 8 weeks and a stable dose of up to 3 antiepileptic medications may participate in a research trial at approximately 30 locations.

Trial objectives include investigating whether iv SPM 927 is safe and well tolerated when given twice daily for a short period of time and identifying the appropriate infusion rate(s).

Subjects will receive SPM 927 as a 30-, 15- or 10- minute infusions twice daily for 2 - 5 days based on notification by the research doctor and subject choice. Subjects will remain on the same stable dose as received in the OLE trial.

Trial procedures will include medical history update, physical/ neurological exams, ECGs, blood /urine sample collections and seizure diary completion.

Subjects completing the trial will return to the OLE trial to resume dosing with oral SPM 927.

Inclusion Criteria:

• Partial seizures with or without secondary generalization.

Exclusion Criteria:

• Subject has previously received iv lacosamide.
• Subject meets the withdrawal criteria for the open-label extension trial.