Intradermal Phleum pratense allergoid immunotherapy. Double-blind, randomized, placebo-controlled trial

Area of Science:

• Allergology
• Immunology
• Clinical Medicine

Background:

• Intradermal allergen administration is common for diagnosis but less explored for immunotherapy.
• Limited experience exists with specific allergen immunotherapy using the intradermal route.

Purpose of the Study:

• To assess the efficacy and safety of intradermal immunotherapy with glutaraldehyde-polymerized Phleum pratense allergen extract.
• To evaluate its impact on patients with grass pollen-induced rhinoconjunctivitis.

Main Methods:

• A multicentre, randomized, double-blind, placebo-controlled trial involving 12-65 year olds with grass pollen allergy.
• Participants received six weekly doses of placebo, 0.03 μg, or 0.06 μg P. pratense allergoid.
• Primary endpoint was the combined symptom and medication score (CSMS); secondary endpoints included conjunctival provocation tests, IgE/IgG4 levels, and safety.

Main Results:

• The 0.06 μg P. pratense allergoid dose significantly reduced CSMS and improved conjunctival provocation test tolerance compared to placebo after the first pollen season.
• Specific IgE levels significantly decreased after the second pollen season in the 0.06 μg group.
• No significant changes in IgG4 levels were observed, and only one grade 2 systemic reaction occurred.

Conclusions:

• Intradermal immunotherapy with P. pratense allergoid is effective and safe for treating grass pollen-induced rhinoconjunctivitis.
• It leads to reduced symptoms, improved tolerance, and decreased specific IgE levels.