The protocol was amended for the following reasons: - To introduce a visit window of up to an additional 7 days maximum to the end of the Study Drug-Free Period to facilitate planning in compliance with the protocol. - To introduce a visit window of ±3 days for V2 to V7 in order to bring N01395 in line with the visit windows applied to other studies using BRV and to take into account practical considerations of requiring subjects to return to the clinic (in order to allow greater flexibility). - To clarify the timing of V7 throughout the protocol. - To update details of some of the team members as the Study Sponsor Physician, Clinical Project Manager (CPM), Clinical Program Director, and Clinical Trial Biostatistician had changed since the protocol was written. - To make some minor revisions to the schematic diagram for the study to show the plan for the visits at the end of the study more clearly and to clarify wording on a footnote pertaining to the inclusion/exclusion criteria.

The protocol was amended for the following reasons: - To change the wording in the inclusion and exclusion criteria to make clear that subjects may have only been receiving LEV for up to 16 weeks prior to V1 at a dose of 1 g/day to 3 g/day. Previously, subjects who took LEV for more than 12 weeks prior to V1 were to be excluded; however, 12 weeks was considered by the Investigators to exclude a number of subjects who developed nonpsychotic behavioral side effects due to LEV, which were recognized at a time that it was too late to schedule and perform a Screening Visit no later than 12 weeks after the start date of LEV. This was partially due to the broad spectrum of nonpsychotic behavioral side effects and the different manifestations of nonpsychotic behavioral side effects that could have been expressed by the patient and/or a relative or close friend. It was necessary to state in the inclusion criteria that the maximum period of 16 weeks should have applied only for the recommended therapeutic dose ranging from 1 g/day to 3 g/day as doses below this range were not considered to be therapeutic. Changes were also made throughout the protocol to reflect the change from a 12-week period to a 16-week period and to specify that the Baseline for nonpsychotic behavioral side effects started when the first LEV dose at the therapeutic approved dose (1 g/day to 3 g/day) was started. - To include a clear definition of abstinence as an acceptable method of contraception, where abstinence was defined as “true abstinence” according to Medicines and Healthcare products Regulatory Agency guidance. - To update wording pertaining to suicide attempts and suicidal ideation captured by the Columbia-Suicide Severity Rating Scale (C-SSRS), in order to ensure the protocol was consistent with this global change for all UCB protocols.

The protocol was amended for the following reasons: - To include further details on the permitted dose adjustments during the Treatment Period in the Treatment(s) to be administered section (Section 7.2) to be consistent with the text in Study description (Section 5.1) of the protocol. - To change the restriction for concomitant non-AEDs as the endpoints for the N01395 study did not require that strong hepatic inducers (which could have caused fluctuations in BRV concentrations) were to be restricted. - To clarify the documentation of the Patient Global Evaluation Scale (P-GES), Investigator Global Evaluation Scale (I-GES), and Investigator Global Evaluation of nonpsychotic Behavioral Side Effects (I-GEBSE) questionnaires during the study and to include the 7 items on the I-GEBSE to be consistent with the level of detail of presentation of the P-GES and I-GES. The numbering of the list of items in the P-GES and I-GES was removed in order to make the presentation consistent with the eCRF, which did not contain numbering in the lists. - To update the name of the Global Clinical Safety and Pharmacovigilance department to Drug Safety (DS) due to a change in the organizational structure at UCB, and to update the contact details for serious adverse event (SAE) reporting due to the formation of a new data processing team at UCB. - To correct a typographical error in the schedule of study assessments and to make some minor style and formatting changes throughout the protocol in order to ensure the document styles were consistent with the current template requirements.

The protocol was amended for the following reason: - Based on review of the study objectives, the exploratory nature of the study design, and unanticipated recruitment challenges, the sample size was reassessed. The sample size for N01395 was reduced from the previous total of 100 subjects entering the BRV Treatment Period to a minimum of 32 subjects with the expectation that at least 30 subjects would receive at least 1 dose of BRV. This amendment was not due to any changes in the adverse event (AE), safety, or tolerability profile for BRV.