Phase I Double-Blind Randomized Placebo-Controlled Trial of Gaxilose for Urinary Xylose Cut-Off in Hypolactasia Diagnosis in Children Aged 5-11 Years

The primary objective of this clinical trial is to establish a **urinary cut-off point of xylose** following a single dose of Gaxilose (LacTEST 0.45g) in healthy children aged 5 to 11 years, for the diagnosis of **hypolactasia**. This is clinically relevant as it aims to provide a non-invasive diagnostic tool for hypolactasia, which is a condition characterized by reduced ability to digest lactose due to low levels of lactase enzyme. Accurate diagnosis is crucial for managing dietary intake and preventing symptoms associated with lactose intolerance.

Secondary objectives include assessing the safety and tolerability of a single oral dose of 0.45g of Gaxilose in subjects between 5 and 11 years of age. Evaluating these parameters is essential to ensure the safe use of Gaxilose in the pediatric population, thereby supporting its potential application in clinical settings.

The clinical trial focuses on establishing a urinary cut-off point of xylose after a single dose of Gaxilose (LacTEST 0.45g) for the diagnosis of **hypolactasia** in a pediatric population. The study involves healthy male and female children aged between 5 and 11 years. Participants are required to be in good health with no baseline gastrointestinal conditions and should regularly consume lactose-containing products without exhibiting signs or symptoms of intestinal lactase deficiency. The trial does not involve a vulnerable population. The sponsor has not provided information regarding the total number of participants in the study.

The clinical trial is designed as a **Phase I**, single-centre, double-blind, randomized, placebo-controlled study aimed at determining the urinary xylose cut-off point for the diagnosis of **hypolactasia** in children aged 5 to 11 years. The trial involves the administration of a single dose of **Gaxilose** in the form of an oral solution, known as LacTEST 0.45 g. The primary objective is to establish a urinary cut-off point of xylose for diagnosing hypolactasia in healthy subjects within the specified age range. The trial is expected to commence recruitment on April 17, 2023, and conclude by October 17, 2023.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to assess eligibility based on specific criteria. These criteria include being in good health, regularly consuming lactose-containing products, and having no baseline gastrointestinal conditions. The screening visit will ensure that participants have no signs or symptoms associated with intestinal lactase deficiency. Following the screening, participants will be randomized to receive either the active treatment or a placebo. The study will include follow-up visits to monitor the pharmacokinetic parameters of urinary xylose excretion, specifically focusing on the maximum urinary excretion rate detected at intervals of 0-3, 3-4, and 4-5 hours, as well as the total xylose excreted (Ae0-5). All urine samples will be analyzed at a designated laboratory.

The trial will also monitor secondary endpoints, including the incidence of adverse events and any relevant changes from baseline in laboratory test results and vital signs. The expected length of participant involvement is from the initial screening through to the end-of-study visit, which will occur after the final follow-up assessments. Conditions that may lead to early termination from the study include non-compliance with study procedures or the occurrence of significant adverse events. The trial is conducted under strict adherence to ethical guidelines, ensuring the safety and well-being of all participants throughout the study duration.

The clinical trial involves the administration of **Gaxilose**, marketed under the name LacTEST 0.45 g polvo para solución oral. This experimental medication is formulated as an **oral solution** and is intended for the diagnosis of hypolactasia. The active substance, Gaxilose, is of chemical origin and is classified under the ATC code V04CX, which denotes other diagnostic agents. The pharmaceutical form is a powder for oral solution, and the medication is administered orally. The trial is designed to determine the urinary xylose cut-off point following a single dose of Gaxilose in children aged 5 to 11 years.

In this study, a **placebo** is used as a comparator treatment to maintain the double-blind and randomized nature of the trial. The placebo is administered in the same pharmaceutical form and via the same route as the experimental medication to ensure consistency in the administration process. The frequency of administration for both the experimental medication and the placebo is a single dose, aligning with the trial's objective to establish a urinary cut-off point of xylose after one administration.

Participant compliance is monitored through standard clinical trial procedures, ensuring adherence to the dosing schedule and accurate collection of urinary samples for analysis. The trial does not involve any additional non-experimental treatments or standard-of-care therapies, focusing solely on the effects of the single dose of Gaxilose compared to the placebo. The study is conducted under the sponsorship of VENTER PHARMA S.L., with the medication authorized for use in Spain under the marketing authorization number 75797.

Efficacy in this clinical trial will be assessed by establishing a urinary cut-off point of **xylose** after a single dose of Gaxilose (LacTEST 0.45g) in healthy children aged 5 to 11 years, for the diagnosis of **hypolactasia**. The primary endpoint involves pharmacokinetic analysis of urinary xylose excretion, which will be evaluated based on parameters such as the maximum urinary excretion rate detected at intervals of 0-3, 3-4, and 4-5 hours, the mean time during the corresponding interval (Tmax), and the total xylose excreted (Ae0-5). All urine samples will be analyzed at a laboratory located in Hospital Universitario de Getafe.

Secondary endpoints include the incidence of adverse events (AEs), as well as relevant and abnormal changes from baseline in laboratory test results, and changes to vital signs in the treatment arm compared to the control arm. These assessments will provide comprehensive data on the safety and efficacy of the intervention in the specified pediatric population.