Biological Standardization of Dermatophagoides Allergen Extracts in Allergic Patients Using Dermatophagoides pteronyssinus and Dermatophagoides farinae Solutions

The primary objective of this study is the **biological standardization** of the allergenic extract of **Dermatophagoides pteronyssinus**, which is representative of the homologous group of Dermatophagoides mites. This is crucial for ensuring the consistency and efficacy of allergen extracts used in diagnostic and therapeutic applications for individuals with **allergies**. The study is conducted in two phases. In the first phase, the concentration of Dermatophagoides pteronyssinus is determined. In the second phase, the sensitivity and specificity of the Dermatophagoides pteronyssinus extract and the Dermatophagoides farinae extract are assessed. These evaluations are essential for optimizing the accuracy of allergy testing and improving patient outcomes in allergen-specific immunotherapy.

The clinical trial focuses on individuals diagnosed with **allergies** to Dermatophagoides pteronyssinus, a common allergen. The study population comprises adults aged between 18 and 50 years, inclusive of both male and female participants. The trial does not involve a vulnerable population. Participants are selected based on their residence in geographic areas where Dermatophagoides pteronyssinus is prevalent, such as the Mediterranean coast, known for its humidity and mild temperatures. The sponsor has not provided the total number of participants. Lifestyle factors such as diet and physical activity are not specified as considerations for this trial. Key inclusion criteria include a positive skin prick test and specific IgE test results, while exclusion criteria involve ruling out IgE-mediated sensitization to the allergen. Participants must be capable of understanding the study's purpose and have provided informed consent.

The clinical trial is designed to evaluate the **biological standardization** of allergenic extracts derived from **Dermatophagoides pteronyssinus**. This trial is structured as a Phase II, randomized, double-blind, controlled study, with an estimated duration extending until March 31, 2026. The trial is divided into two phases, each with distinct objectives. The first phase focuses on determining the concentration of the **Dermatophagoides pteronyssinus** extract, while the second phase assesses the sensitivity and specificity of the extracts from both **Dermatophagoides pteronyssinus** and **Dermatophagoides farinae**.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on specific criteria, such as residing in a geographic area where **Dermatophagoides pteronyssinus** is prevalent and having a positive skin prick test. The trial includes follow-up visits to monitor the response to the allergenic extracts and to perform skin prick tests with both positive and negative controls. The end-of-study visit will conclude the participant's involvement, with a final assessment of the primary and secondary endpoints, including the area of the wheal produced and the safety profile of the extracts.

The expected length of participant involvement is approximately 18 months, with conditions for early termination including adverse reactions or withdrawal of consent. The primary endpoints focus on the wheal area induced by the extracts and the dose-response relationship, while secondary endpoints include the evaluation of extract sensitivity and specificity, as well as safety assessments. The trial aims to provide valuable data on the efficacy and safety of the allergenic extracts, contributing to the standardization of diagnostic procedures for **allergies**. Participants will be monitored closely throughout the trial to ensure adherence to the protocol and to address any potential adverse events promptly.

The clinical trial involves the use of several **experimental medications** and control substances, each administered as a **solution for skin-prick test**. The primary experimental medication is the "Diagnóstico prick Dermatophagoides pteronyssinus," which contains the active substance **Dermatophagoides pteronyssinus**. This substance is an allergenic extract derived from mites of the species Dermatophagoides pteronyssinus. The pharmaceutical form is a solution specifically designed for skin-prick testing, and it is administered via **subcutaneous use**. The dosage is standardized at 10 mg/ml, with a maximum daily and total dose of 10 mg/ml. The treatment period is limited to one day. This medication is not a pediatric formulation and is not classified as an orphan drug.

In addition to the primary experimental medication, the trial includes a positive control known as "Diagnóstico prick control positivo," which contains **histamine dihydrochloride**. This chemical substance is also provided in a solution for skin-prick testing and is administered subcutaneously. The dosage and administration schedule are consistent with the primary experimental medication, with a concentration of 10 mg/ml and a maximum daily and total dose of 10 mg/ml over a one-day treatment period.

The trial also utilizes a negative control, "Diagnóstico prick control negativo," which contains **sodium chloride**. This chemical is used as a physiological serum in the form of a solution for skin-prick testing. Like the other substances, it is administered subcutaneously with a concentration of 10 mg/ml and a maximum daily and total dose of 10 mg/ml, also limited to a one-day treatment period.

Participant compliance with the dosing schedule is monitored throughout the trial to ensure accurate and reliable results. The trial aims to biologically standardize the allergenic extract of Dermatophagoides pteronyssinus and assess its sensitivity and specificity in comparison to other extracts. All substances are provided by ASAC Pharmaceutical Inmunology and are authorized for use in this clinical trial.

Efficacy in this clinical trial will be assessed through a series of primary and secondary endpoints. The primary endpoints include the measurement of the area of the wheal (mm²) that occurs at the cutaneous level following the administration of the extracts in the skin-prick test. This will facilitate the calculation of the primary endpoint. Additionally, the dose/response relationship will be estimated for each patient through regression analysis of area values versus concentration in PNU/ml. The theoretical concentration of extract that produces a papule equivalent to that produced by a solution of **histamine dihydrochloride** at 10 mg/ml will also be determined.

Secondary endpoints will focus on evaluating the sensitivity and specificity of the extract concentration as defined in the main objective of the study. Safety will be assessed through a descriptive analysis of any adverse reactions that may occur during the course of the study. The trial is structured in two phases, with the first phase focusing on the biological standardization of the allergenic extract of **Dermatophagoides pteronyssinus**. The second phase will assess the sensitivity and specificity of the **Dermatophagoides pteronyssinus** extract and the **Dermatophagoides farinae** extract based on the concentration determined in the first phase.