An interventional study of Slow release, phenylalanine-free protein substitute tablets in Phenylketonuria (PKU) and Hyperphenylalaninemia, Brain Diseases, Metabolic, Inborn and Brain Disorder, Metabolic, sponsored by metaX Institut fuer Diatetik GmbH. Not yet recruiting at 1 site in United Kingdom. Open to participants aged 3 Years to 18 Years. Per ClinicalTrials.gov, last updated 2026-10-15.
Sponsored by metaX Institut fuer Diatetik GmbH · Not applicable, Interventional, and Treatment
XPhePiccosMR is a prospective, single-arm, open label, observational study that aims to evaluate the acceptability and tolerability of XPhe Piccos, a slow-release, phenylalanine-free protein substitute in the form of tiny tablets, for use in the dietary management of phenylketonuria (PKU) in children aged three years and older.
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:
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.
191 studies on the registry are indexed under Phenylketonurias; 40 are open to participants now.
This study's planned enrollment of 10 is below the median of 27 across 122 interventional studies indexed under Phenylketonurias.
Browse Phenylketonurias studies →metaX Institut fuer Diatetik GmbH is the lead sponsor of 3 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Subjects who are currently taking a second stage phenylalanine-free/low-Phe protein substitute will be recruited. Subjects will take the study product for 7 days. Subjects will replace some or their entire protein substitute with the study product. The appropriate amount of protein substitute will be calculated to provide the same amount of protein as their usual protein substitute. Intervention: Dietary Supplement: Slow release, phenylalanine-free protein substitute tablets.
Dietary Supplement: Slow release, phenylalanine-free protein substitute tablets
The slow release, phenylalanine-free protein substitute in tablet form (XPhe Piccos) is a food for special medical purposes (FSMP) for use in the dietary management of Phenylketonuria or Hyperphenylalaninemia. The product is suitable from 3 years of age and over. XPhe Piccos are a highly concentrated phenylalanine-free protein supplement in the form of very small tablets/pellets enriched with vitamins, minerals and trace elements. XPhe Piccos are characterized by a prolonged release of the amino acids.
Rate of patient compliance with consumption of the prescribed volume of study product
Compliance with the recommended intake of the usually prescribed protein substitute is assessed by the dietitian at baseline. Usage and compliance with the study product are recorded daily from day 1 to day 7 using a standardised form. Using the form, patients have to record the amount of the study product consumed in comparison to the prescribed doses. The reason for not consuming the full dose will be recorded by the patient/parent/caregiver as free text. Patients are asked to state whether the study product is easy to prepare with yes or no.
Time frame: daily; from day 1 to day 7
Gastro-intestinal tolerance
Gastro-intestinal side effects (including diarrhoea, constipation, bloating or abdominal distension, nausea, vomiting, burping, flatulence or regurgitation and abdominal discomfort or pain) will be assessed at baseline and daily (from day 1 to day 7) via a standardised questionnaire using the following scale: none today, mild, moderate, or severe / really troublsome.
Time frame: daily; from day 1 to day 7
Patient Acceptability
Accepatbility (ease of use, taste, texture, palatability) will be assessed daily during the study period and at the end of the study via a standardised questionnaire with a rating scale of 5 (great) to 1 (terrible).
Time frame: daily; from day 1 to day 7
Metabolic Control
Weekly routine finger prick blood spots will be collected and analysed for phenylalanine and tyrosine as is usual clinical practice.
Time frame: baseline (day 1) and day 7
Incidence of study product emergent events
All adverse events will be recorded throughout the study (as and when they occur). There is no specific time frame as the frequency of adverse events can not be predicted. But as the study product is already commercially available occurance of any adverse event is unlikely.
Time frame: throughout the study; from day 1 to day 7
Plan to share: No — No IPD will be shared with other researchers.
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for May 2027, 6 months later.
Of 33 interventional studies with no phase under Phenylketonurias, half reached primary completion within 22 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 28. This study's planned 6 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
metaX Institut fuer Diatetik GmbH