Evaluation of Sensitivity and Specificity of Lepidoglyphus destructor Extract in Skin Prick Testing for Lepidoglyphus destructor Allergy

The primary objective is to assess the sensitivity and specificity of multiple concentrations of the allergen extract derived from Lepidoglyphus destructor in skin‑prick testing, together with efficiency, positive and negative predictive values, and likelihood ratios, to identify the optimal concentration for routine diagnostic use. This evaluation is clinically relevant because accurate concentration selection enhances diagnostic precision for allergy to Lepidoglyphus destructor. Secondary objectives include:

• Evaluation of the safety and tolerability of the L. destructor extract during testing.
• Characterization of each participant’s allergenic profile using the ALEX technique (ALEX technique).

The sponsor did not provide the total number of participants. The trial enrolled individuals aged 12 to 70 years of both sexes who provided signed informed consent. Participants were selected on the basis of a documented allergy to Lepidoglyphus destructor or the absence of sensitization, as determined by specific IgE levels (> 0.35 kU/L for sensitized subjects, < 0.35 kU/L for non‑sensitized subjects) and corresponding prick‑test results. All subjects required a positive response to the histamine positive control and a negative response to the saline negative control. Women of childbearing potential needed a negative urine pregnancy test and adherence to highly effective contraception throughout the study. General health criteria included a positive clinical history of inhalant allergy (rhinitis, rhinoconjunctivitis, or asthma) to perennial allergens or pollens, with no other exclusionary medical conditions reported. Lifestyle considerations were limited to the requirement of stable allergy‑related health status at enrollment.

The study is a prospective, non‑randomized, controlled trial conducted over an estimated four‑month period (June 13 2026 – October 13 2026) to evaluate the diagnostic performance of Lepidoglyphus destructor extract in skin‑prick testing. After obtaining signed informed consent, participants undergo a screening visit during which specific IgE levels, clinical allergy history, and baseline prick‑test responses to the positive (histamine dihydrochloride) and negative (sodium chloride) controls are documented; eligibility requires a positive control wheal ≥ 3 mm and a negative control wheal < 3 mm. Eligible subjects are then assigned to either a true‑positive cohort (IgE > 0.35 kU/L and positive prick test to L. destructor) or a true‑negative cohort (IgE < 0.35 kU/L, negative prick test, and no clinical reactivity to L. destructor). At the baseline visit, the test extract is applied at multiple concentrations, and the primary endpoint, the wheal area (mm²), is measured alongside responses to the controls. Subsequent follow‑up visits, scheduled at predefined intervals, monitor safety parameters, record any adverse events, and perform allergen profiling (ALEX technique). The trial concludes with an end‑of‑study visit during which final safety assessments and data collection are completed. Participant involvement spans from screening through the end‑of‑study visit, with each individual remaining in the study for the duration of the testing protocol unless early termination criteria are met, such as occurrence of a serious adverse event, pregnancy, or non‑compliance with protocol requirements. The investigation will generate data on sensitivity and specificity, as well as predictive values, to inform the optimal concentration of the Lepidoglyphus destructor extract for diagnostic use.

The investigational product is Lepidoglyphus destructor extract 450 µg/mL solution for skin‑prick test. It is supplied as a sterile solution for skin‑prick test, provided in single‑dose vials. The administered dose is 2 drops (Gtt) applied to the skin. The route of administration is cutaneous use. The extract is applied once per testing session to evaluate allergen sensitivity.

Skin Prick Test Negative control contains sodium chloride and is formulated as a solution for skin‑prick test. The control is administered as 2 drops applied cutaneously. It serves as the background control for each testing session.

Skin Prick Test Positive control contains histamine dihydrochloride and is also supplied as a solution for skin‑prick test. The dose is 2 drops applied cutaneously. This positive control confirms reactivity of the test site.

All administrations are performed by trained personnel under controlled conditions. Each drop is placed on the forearm and punctured with a standardized lancet. Participants are observed for a minimum of 15 minutes after application to record wheal and flare responses. Documentation of the administered product, dose, time, and observed reaction is required for compliance monitoring.

The primary efficacy assessment will be based on the Area (mm²) of wheals induced by each concentration of the Lepidoglyphus destructor extract, as measured during the skin prick test. Wheal dimensions will be recorded in square millimetres for the test extract, the positive control (histamine dihydrochloride) and the negative control (sodium chloride) immediately after administration.

Collected wheal‑area data will be analysed to determine the sensitivity and specificity of each extract concentration, as well as the positive and negative predictive values and likelihood ratios. Comparative analyses will be performed across concentrations and controls to identify the optimal diagnostic concentration for the allergen preparation.