PDE MAX is a single arm prospective, feasibility study in up to 15 participants aged one (1) year and over of PDE MAX for the dietary management of Pyridoxine Dependent Epilepsy.

PDE Max is a newly-developed product designed specifically to meet the nutritional requirements of patients following a lysine-restricted diet for PDE.

This is a feasibility study to evaluate PDE MAX, a food for special medical purposes (FSMP) for use in the dietary management of Pyridoxine Dependent Epilepsy (PDE) with regards to acceptability, tolerability, adherence and effect on metabolic control.

Participants will be given an eight-week supply of PDE MAX and they will be asked to complete a daily diary and short questionnaire to record information on: adherence, gastrointestinal tolerance, palatability and how the product is used.

Blood and urine samples will be taken at the beginning and end of the study to measure several biochemical parameters.

Physical and neurological assessments will be carried out by the local Metabolic Consultant at the beginning and end of the study.

Routine monitoring of lysine levels will continue.

Inclusion Criteria:

• Diagnosis of Pyridoxine Dependent Epilepsy (PDE), biochemically and/or genetically confirmed.
• Males or females aged one (1) year and above. Any participant aged 16 years and over at screening must have the capacity to consent for themselves.
• Currently following a lysine-restricted diet for a minimum of four (4) weeks prior to screening.
• Willing to take the study product and follow advice given by the dietitian.
• Willingly given, written, informed consent from patient or parent/guardian.
• Willingly given, written assent (if appropriate).

Exclusion Criteria:

• Inability to comply with the study protocol, in the opinion of the investigator.
• Use of additional macro/micronutrient supplements during the study period, unless clinically indicated and prescribed by the investigator, such as but not limited to arginine and pyridoxine. In which case, supplementation must have started four (4) weeks prior to screening with no anticipated changes to intakes during the study duration.
• Participants who are pregnant / breastfeeding at the start of the study or planning to become pregnant during the study period. Participants of child-bearing potential will be required to undergo pregnancy test prior to enrolment.

N.B.: Participants who become pregnant unexpectedly during this study may, in consultation with their doctor, continue on the study's dietary product if they wish but will not have any investigations that would not normally be carried out during pregnancy.

• Allergy to any ingredient present in the study product.
• Other concurrent medical or psychiatric conditions, which, in the opinion of the Investigator, would place the subject at increased risk, preclude obtaining voluntary consent/assent or compliance with required study procedures, or would confound the objectives of the study.
• Is participating in any other interventional study and has received any other investigational drug, product or device within 30 days prior to screening or are taking part in a non-medication study which, in the opinion of the investigator, would interfere with study compliance or outcome assessments.