A Phase 2, Prospective, Interventional, Open-Label, Multi-Site, Extension Study to Assess the Long-Term Safety and Tolerability of TAK-935 (OV935) as Adjunctive Therapy in Patients With Rare Epilepsy

The drug being tested in this study is called TAK-935 (OV935). This global, open-label study
will assess the safety and tolerability of TAK-935 for 2 years in patients who participated
in previous short-term efficacy/safety studies of TAK-935. All patients will receive TAK-935
treatment.

Patients who rollover from previous blinded study will undergo up to 2 weeks of titration
followed by 102 weeks of maintenance period. Patients who rollover from an open-label study
will continue on their current dose for 104 weeks. There will be a 4-week safety follow-up
after the last dose, including a 2-week dose tapering period.

Inclusion Criteria:

1. Patients must have participated in a previous TAK-935 study and meet one of the
following conditions:

- Successfully completed a TAK-935 clinical study

- In the opinion of the investigator, the patient has the potential to benefit from the
administration of TAK-935

Exclusion Criteria:

1. Clinically significant disease, that, in the investigator's opinion, precludes study
participation

2. Enrollment in any other clinical trial involving an investigational drug, device, or
treatment in the past 6 months (with the exception of an antecedent study involving
TAK-935)