Acceptability and Tolerance Market Research of a Slow Release, Phenylalanine-free Protein Substitute for the Dietary Management of Phenylketonuria

The principle treatment for children with Phenylketonuria (PKU) or Hyperphenylalaninemia (HPA) is a low protein diet. Part of this treatment requires the administration of a protein substitute in order to meet basic protein requirements for normal growth and development. Several brands of protein substitutes for PKU/HPA are already available in various presentations. However, compliance with taking protein substitutes continues to be a challenge. As a low protein diet is usually recommended for life, long term compliance is always a major concern. As a result, improving the choice in terms of product type may aid compliance.

XPhe Piccos is a slow release, phenylalanine-free protein substitute in a tiny tablet form, enriched with vitamins, minerals and trace elements and designed for children and adults with PKU/HPA. XPhe Piccos is a food for special medical purposes (FSMP), as defined by the Delegated Regulation (EU) 2016/128 of 25 September 2015 supplementing Regulation (EU) No 609/2013 of 12 June 2013, used for the dietary management of PKU/HPA.

It is anticipated that XPhe Piccos will be a suitable alternative option for patients with PKU/HPA broadening the variety of protein substitutes they can choose from in order to suit their lifestyle and preferences.

This is a prospective, single-arm, open-label, observational tolerance study with 10 children with PKU. Subjects who are currently taking a second stage protein substitute will be recruited for a 7-day trial, taking the new ready-to-use slow release, phenylalanine-free protein substitute tablets to evaluate the tolerability and acceptability of the study product. Therefore, subjects will replace some or all of their usual protein substitute with the new product.

During the 7-day trial subjects or caregivers will be asked to complete a daily questionnaire recording information on:

• Usage and compliance
• Ease of use and any issues with administration
• Any gastro-intestinal side-effects.

A questionnaire will also be completed at the beginning and end of the study that will consider perceptions about taste, appearance, smell, ease of administration of the usually used product and the study product; how it is taken; and any other problems or symptoms.

The amount of tablets prescribed will be calculated to provide the same amount of protein as their usual protein substitute.

Subjects will continue to have weekly finger-prick blood spot tests as is routine in PKU. The results whilst on the study product will be compared with results whilst on their usual protein substitute.

10 children with PKU will be recruited. When an appropriate subject has been identified, a study information sheet will be sent to the subject or parents/ caregivers. They will be invited to request further information about the study if they wish by contacting the Lead Dietitian.

Recruitment of each patient will be by written informed consent, which will be completed by the parents/ primary caregivers and taken by the Lead Dietitian. Children will also complete an assent/consent form and will receive an information sheet, if considered appropriate for their level of understanding.

Inclusion criteria

• Diagnosis of PKU or HPA requiring a phenylalanine-free protein substitute.
• Subjects who are already taking a phenylalanine-free protein substitute and are willing to try the study product for 7 days.
• Subjects aged 3 years and above.
• Written informed assent/consent obtained from subject and/or parental caregiver, depending on subject age.

Exclusion criteria

• Presence of serious concurrent illness.
• Lead Dietitian's uncertainty about the willingness or ability of the patient to comply with the protocol requirements
• Participation in any other studies involving investigational or marketed products concomitantly or within two weeks prior to entry into the study.
• Any subject having taken antibiotics over the previous 2 weeks leading up to the study.
• Subjects less than 3 years of age