Study to assess the pharmacokinetics, tolerability, and food effect of PTC923 in healthy subjects
This Phase I clinical trial is studying an experimental medicine called PTC923 in healthy adults. PTC923 is being developed to treat phenylketonuria (PKU), a rare genetic condition where the body cannot break down an amino acid found in protein-rich foods like meat and eggs. If untreated, PKU can lead to serious brain damage and learning difficulties. Because this is an early study, researchers want to see how the human body absorbs, breaks down, and clears the medicine. They also want to find out whether eating a meal changes how the drug works, and whether it behaves differently in people of Japanese background compared to non-Japanese backgrounds. Participants will take PTC923 as a drink and attend up to nine visits, including overnight stays at a UK research unit over about six weeks. Doctors will carry out regular health checks and blood tests throughout.
At a glance
What is this study about?
Phenylketonuria (PKU) is a rare inherited condition. People born with PKU lack the ability to break down a natural substance called phenylalanine, which is found in protein-rich foods such as dairy, meat, and nuts. Without careful management, phenylalanine builds up in the blood and brain. This buildup can cause serious, permanent learning disabilities, seizures, and mood problems.
Researchers are developing a new study medicine called PTC923. It works by boosting levels of a helpful substance in the body called BH4, which helps break down phenylalanine. Before testing whether PTC923 can treat people with PKU, scientists must first learn how it behaves in healthy human volunteers.
This trial focuses on what doctors call 'pharmacokinetics'—how the body absorbs, spreads, breaks down, and removes the drug. The researchers want to check whether food changes how the medicine is absorbed, and whether it acts the same way in people of Japanese heritage compared to non-Japanese volunteers. The results will help doctors choose the safest, most effective dose for future patient trials.
Key takeaways
- Phase I study testing a new PKU treatment in healthy volunteers aged 18 to 55.
- Investigating how the body absorbs, breaks down, and clears the medicine PTC923.
- Checking whether taking the medicine with food changes how it works.
- Comparing responses between Japanese and non-Japanese participants.
- Involves up to nine visits (including overnight stays) over around six weeks in the UK.
Who may be eligible?
This study is looking for healthy men and women aged 18 to 55 years. Volunteers must have a body mass index (BMI) between 18.5 and 30.0 kg/m², which falls within the healthy to slightly overweight range. You must be a non-smoker and cannot have used any tobacco or nicotine products, including vapes or nicotine patches, for at least two weeks before joining.
The trial is open to two specific groups: people of Japanese heritage (born in Japan with Japanese parents and grandparents) and people of non-Japanese heritage (specifically European, White Latin American, or African descent). Comparing these groups helps researchers understand if background influences how the body processes the treatment.
To protect safety, female volunteers must not be pregnant or breastfeeding. Both men and women who could have children must agree to use reliable contraception during the study and for a set time afterwards, unless they practise complete sexual abstinence as part of their normal lifestyle.
Could this study suit you?
Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.
- I am between 18 and 55 years old.
- My BMI is between 18.5 and 30.0 kg/m².
- I do not use tobacco, nicotine, or e-cigarettes (and have not for at least two weeks).
- I am either of Japanese heritage or of European, White Latin American, or African descent.
- I am not pregnant, not breastfeeding, and willing to use approved contraception.
- I am able to attend up to nine visits, including overnight stays in the UK.
What does participation involve?
Taking part lasts around six weeks (about one and a half months) and involves up to nine visits to a specialised clinical research facility in the UK. Some of these visits will require overnight hospital stays so the research team can monitor you closely around the clock.
During the trial, you will receive PTC923, which comes as a powder that is mixed with water and swallowed. Most volunteers will take one single dose after a meal. A small group of Japanese volunteers will take two doses a few days apart—once after eating and once on an empty stomach—to see how food affects the medicine.
At your visits, doctors will perform regular physical examinations, check your heart rhythm (ECG), monitor your blood pressure, and take blood and urine samples. These samples show exactly how much medicine is in your bloodstream at different times.
Potential risks and benefits
Locations (1)
- Fortrea Clinical Research Unit - LeedsCity onlyLeeds, England
Common questions
Do I need to have PKU to join this study?
No. This trial is specifically designed for healthy volunteers without PKU to test the safety of the medicine first.
How is the medicine taken?
PTC923 is a powder that is dissolved in water and taken by mouth as a drink.
Will I have to stay overnight at the clinic?
Yes. The trial requires up to nine clinic visits in total, and some of these visits include overnight stays so staff can monitor you.
Why are researchers comparing Japanese and non-Japanese volunteers?
Different genetic backgrounds can sometimes affect how quickly the liver and kidneys process medicines. Comparing both groups helps ensure future doses are safe for everyone.
Can I leave the trial if I change my mind?
Yes. Joining a clinical trial is completely voluntary, and you can withdraw at any time without any penalty.
How to find out more
Med Info
Always speak to your GP or specialist before deciding to take part in a study.
Discussion
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