Characterization of Epilepsy Patients BEEP 2b

This pilot study is exploratory research to characterize the "generic brittle" (GB) patient
and to identify major causes for generic brittleness in epilepsy patients who are sensitive
to antiepileptic drug (AED) formulation changes.

The primary aim of this BEEP2b study is to perform individual pharmacokinetic (PK) similarity
testing of brand and generic AEDs in "probably GB" patients (N=12),who were selected on the
basis of having GB-defining factors from the BEEP2a study, in order to confirm whether these
factors are predictive of a generic brittle response to product switching. The study design
involves a randomized, double-blind, multiple-dose, complete four-way replicate crossover
design in which one brand and one generic will be compared in each patient from the patient's
own AED regimen. Associated adverse events (i.e. seizures and side effects) will also be
assessed. Bioequivalence (BE) will not be assessed. Rather, about nine AEDs are expected to
be collectively evaluated. Generic brittleness anticipates that, for individual subjects,
brand and generic may be the same or different, depending upon the underlying basis for
generic brittleness. This exploratory research is focused on understanding individual patient
attributes that contribute to GB, and is not focused on either product development or
comparison of specific products.

Inclusion Criteria:

1. Subject previously completed BEEP2a study, found to be probably GB, and able to
provide informed consent or subject's legally authorized representative is able to
provide informed consent.

2. Subject is male or female between 18 and 76 years of age inclusive.

3. Subject has a diagnosis of epilepsy including focal or primary generalized epilepsy.

4. Subject is taking at least one study antiepileptic drug for the treatment of epilepsy.

5. Subject is an acceptable candidate for venipuncture.

6. Subject is willing to be switched between brand and generic drug.

7. Subject is willing to stop all non-routine OTC medications for 24 hours prior to and
during pharmacokinetic study visits.

8. Subject is willing to maintain stable doses of all other AEDs, including Vagus Nerve
Stimulation parameters for the duration of the study.

Exclusion Criteria:

1. Subject has any medical condition, including a progressive neurological condition,
which in the opinion of the investigator, could jeopardize the subject's health or
would compromise the subject's ability to participate in the trial.

2. Subject has a history of alcohol or drug abuse, which in the opinion of the
investigator, could jeopardize the subject's health or would compromise the subject's
ability to participate in this trial.

3. Subject has a history of previous or current significant psychiatric disorder that
would interfere with conduct of the study.

4. Subject is pregnant or lactating.

5. Subject has severe liver impairment as assessed by alanine aminotransferase (ALT),
aspartate aminotransferase (AST), or total bilirubin levels ≥10 times the upper limit
of normal (ULN).

6. Subject has severe renal impairment as assessed by creatinine clearance lower than
30mL/min, using the Cockcroft-Gault formula.

7. Female subjects of childbearing potential will not be eligible to participate who are
unwilling or unable to use a medically acceptable method of contraception throughout
the entire study period and for one week after the study is completed. Medically
acceptable methods of contraception that may be used by the subject and/or her partner
are: condom with spermicide, diaphragm with spermicide, IUD without progesterone,
vaginal spermicidal suppository, surgical sterilization of their partner(s) or
abstinence.

8. Subject is not willing or able to be adherent to study protocol (e.g. study medication
dosing and any interacting comedication).