1. Patients with confirmed PNPO deficiency via genetic analysis, whose seizures are typically controlled on P5P (oral) therapy.
a. Typically controlled is defined as receiving multiple doses of P5P daily to control seizures. Receiving P5P for a minimum of 30 days.
2. Male and/or female patients.
3. Aged ≥2 years
(3) Patients with previous failed treatment on pyridoxine are eligible for the study (patient should be off pyridoxine for at least 24 hours).
(4) Written informed consent (by parent or guardian if under the age of 18).
You may not be if
1. The patient has any condition or abnormality which may, in the opinion of the Investigator, compromise the safety of the patient, or influence their ability to comply with study procedures.
2. Known or suspected allergy to the trial drug or the relevant drugs given in the trial.
3. Involvement in a clinical research study within 4 weeks prior to screening and/or prior enrollment in the study. Participation in observational registry studies is permitted.
