A Histamine Pharmacodynamic Biomarker to Guide Treatment in Pediatric Asthma (HAS3)

The investigator hypothesizes that children with a hyper-responsive HILD (Histamine Lontophoresis with Laser Doppler monitoring) response type are more likely to have improved asthma control after the addition of the antihistamine LTZ (Levocetirizine) to standard asthma regimen in comparison to children with hypo-responsive HILD type. This study will provide a model for a functional biomarker to inform decision making for therapeutics in children. This work is novel in testing and validating a biomarker accurately and predicting response to asthma treatment in children. This work is significant because it has the potential to alter the current treatment paradigms for children with asthma where response to treatment is predicted a priority. The proposed research will be immediately relevant by expanding knowledge in the field of asthma therapeutics by linking biologically and mechanistically based approaches to an effective and inexpensive treatment for asthma. The primary objective is to determine HILD prediction of therapeutic response in males and females 6-17 years old who identify as African American/Black and Caucasian/White to an antihistamine among children with allergic asthma, and the secondary objective is to develop a robust predictive model of therapeutic response to an antihistamine among children with allergic asthma. There will be 300 participants for approximately 17 weeks. The primary outcome measure of therapeutic response to antihistamine will be determined by change in asthma control as guidelines recognize asthma control as a major goal of therapy. Asthma control will be determined based on the Asthma Control Test (ACT®) (children ≥ 12 years of age) or the Child-Asthma Control Test (C-ACT®) (children \<12 years of age), validated measures to assess asthma control in children. Children with an ACT or C-ACT score \<19 will be classified as having uncontrolled asthma. Assessments will occur at screening, visit 2, 3 and 4 (6 weeks after the participant is started on drug/placebo.) The secondary measures will include assessment of asthma impairment, risk, and quality of life. These assessments will occur at baseline/pre-dose, 6 weeks after starting drug/placebo, and 6 weeks after drug/placebo for both the LTZ and placebo arms. The study team is utilizing HILD a surrogate marker of histamine response and will determine if HILD can predict which participants have improvement in asthma control after treatment with Levocetirizine.