In short
13C-urea is a diagnostic substance used in breath tests to detect Helicobacter pylori infection in the stomach and duodenum. It is already authorised as a medicine in the European Union and appears as an auxiliary agent in one registered Phase 3 trial involving 420 participants, where it is used to confirm whether the infection has been cleared after treatment.
Key points
- 13C-urea is a non-radioactive labelled form of urea used to detect Helicobacter pylori infection.
- It is already authorised as a medicine in the EU, supplied as Helicobacter Test INFAI 75 mg powder for oral solution.
- One Phase 3 trial with 420 participants uses 13C-urea as an auxiliary diagnostic to confirm infection clearance.
- The trial compares a fixed combination treatment against standard first-line therapy for H. pylori infection.
- The main measure is the urea breath test (UBT), where a negative result means the infection has been cleared.
- The trial is currently authorised, meaning it has received approval to proceed.
What is 13C-urea?
13C-urea is a chemically synthesised diagnostic substance. It is urea — a compound naturally present in the human body — labelled with the non-radioactive stable isotope carbon-13 (13C). The substance is authorised as a medicine in the European Union, with the product name Helicobacter Test INFAI 75 mg powder for oral solution. It is also known as Urea [13-C] and Urea C13 in some medicine databases. The authorisation is held by INFAI GmbH. 13C-urea is classified as an "other diagnostic agent" under the ATC code V04CX.
How does 13C-urea work?
The diagnostic principle relies on the activity of the enzyme urease, which is produced by Helicobacter pylori bacteria. When a person with an H. pylori infection swallows 13C-urea, the bacteria break it down and release carbon dioxide containing the 13C label (13CO2) into the exhaled breath. Breath samples are then collected and the ratio of 13CO2 to 12CO2 is measured. Since other urease-producing bacteria are seldom found in the gastric flora, detecting 13CO2 in the breath above a certain limit indicates the presence of H. pylori infection.
Which conditions is 13C-urea used or studied for?
- Helicobacter pylori infection — 13C-urea is used as a diagnostic test to detect this bacterial infection of the stomach and duodenum.
How is 13C-urea given?
13C-urea is given by mouth as a powder for oral solution. The product is dissolved in water before drinking. In the clinical trial data, it is listed as an oral solution for oral use. Other formulations of the same substance exist, including soluble tablets and oral powders in strengths of 45 mg, 50 mg, 75 mg and 100 mg, supplied as breath test kits.
What do the clinical trials show?
One registered trial in the EU Clinical Trials Information System uses 13C-urea. The trial is a Phase 3 interventional study with 420 participants, currently in authorised status. The study investigates a new fixed combination treatment for Helicobacter pylori infection compared with standard first-line therapy. In this trial, 13C-urea is used as an auxiliary diagnostic — the Helicobacter Test INFAI 75 mg powder for oral solution — to perform the urea breath test (UBT) that determines whether the infection has been cleared.
The primary endpoint is the successful clearance of the infection, defined as a negative urea breath test after the eradication treatment is completed. The trial compares the eradication rate between the two treatment arms in the microbiological intention-to-treat (mITT) set.
Earlier clinical work with 13C-urea has been described for another product, Pylobactell. Two clinical trials in a total of 366 patients showed high diagnostic efficiency of the breath test, both before and after H. pylori eradication therapy. A retrospective cohort study also examined the diagnostic validity of the 13C-urea breath test in patients who had undergone gastrectomy, a surgical removal of part or all of the stomach.
What side effects are known?
In the clinical studies performed with 13C-urea for the Pylobactell product, no side effects due to 13C-urea were reported. Because urea is naturally present in the body and only a small additional amount is given, the product is considered safe.