according to recent research released as an abstract for the annual meeting of the American Academy of Allergy, Asthma & Immunology.
Tree pollen season is generally considered to be between February and June, with alder and hazel allergens affecting patients early and oak pollen affecting patients later in the season. Since a major birch allergen, Betula verrucosa 1 (Bet v 1), cross-reacts with alder, hazel, and oak allergens, some patients may experience allergies across the entire tree pollen season from members of this so-called birth homologous group,, senior vice president of research and development at ALK-Abello Americas and International, said in an interview.
According to the U.S. National Health and Nutrition Examination Survey 2005-2006, 16% of 8,086 participants 6 years or older with allergy had a specific immunoglobulin E (IgE) to birch, while 18% had a specific IgE to oak. Patients who reported having hay fever had a specific IgE to birch of 23% and a specific IgE to oak of 26% ().
“Patients who are allergic to birch pollen often experience symptoms in response to pollen from other members of the birch homologous group, which prolong the tree season and increase the symptom burden for these patients,” Dr. Nolte said. “Thus, treatment with SLIT-tablet immunotherapy may be an important treatment option for many allergy sufferers.”
Dr. Nolte and colleagues performed a randomized, double-blind, multinational trial of 634 patients before and during tree pollen season in which participants received a daily SLIT tablet or placebo. Patients were between ages 12 and 65 years with allergic rhinitis, and investigators enrolled patients or without conjunctivitis and with or without asthma. The investigations evaluated the patients’ daily symptom score and daily medication score, which was grouped into the total combined score. The patients were also allowed to use their rescue medications during the trial.
SLIT demonstrates symptom improvement
“Improvement in allergic rhinoconjunctivitis symptoms and reduction in symptom-relieving medication use with the tree SLIT-tablet during birch, alder/hazel, and oak pollen seasons were significant versus placebo and showed internal consistency across almost 4 months of birch and related tree pollen exposure,” Dr. Nolte said.
Patients showed relative improvements in their total combined score of 39.6% for birch, 29.7% for alder and hazel, 36.0% during oak pollen season, and 35.0% during the entire tree pollen season, compared with placebo (all P ≤ .002). Relative daily symptom scores also improved in the group that received oral SLIT, with 36.8% of patients showing improvement during birch season, 26.0% during alder and hazel season, 31.6% during oak season, and 31.6% across all pollen seasons, compared with those taking placebo (all P ≤ .003). A greater number of patients also achieved a relative improvement in daily medication score during birch season (49.2%), alder and hazel season (43.8%), oak season (45.9%) and during the whole of tree pollen season (45.3%), compared with placebo (P ≤ .002).
“The results support the clinical relevance of cross-reactivity between birch, alder/hazel, and oak pollen homologous allergens,” Dr. Nolte said. “Immunologic cross-reactivity is supported by alder, hazel, and oak specific IgE data and IgG4 in responses to the tree SLIT tablet.”
Dr. Nolte said the next step in his team’s research was to evaluate oral SLIT in a phase 3 trial for children aged 5-17 years.
This study was funded by ALK, and the authors received medical writing and editorial assistance from Scott Medical Communications. Dr. Nolte reported that he is a paid employee of ALK.
SOURCE: Nolte H et al. AAAAI, .