Efficacy and safety of sublingual immunotherapy with grass monomeric allergoid: comparison between two different...

Sublingual immunotherapy (SLIT) with monomeric carbamylated allergoid proved to be well tolerated, safe and effective in patients with respiratory allergy. Standard administration regimens are expected to require a long time before clinical benefit can be appreciated. We investigated whether pre-seasonal and perennial regimens differently affect the clinical efficacy of grass pollen SLIT.

Adult patients with allergic rhino-conjunctivitis with/without mild intermittent asthma due to grass pollen were included into this open prospective study and randomised to receive SLIT with a continuous regimen (Group 1: 1,000 AU/week for the entire study period) or a pre-seasonal regimen (Group 2: 5,000 AU/week for 10 weeks/year for 2 years), or on demand drug therapy alone (Group 3) for two years. At entry (November 2005), at the end of the first and second pollen season, a Visual Analogue Scale (VAS) was used to assess patients' well-being. Symptom score and drug consumption were evaluated during the seasons. Methacholine challenge was performed at study entry and conclusion. Adverse events were recorded along the whole study duration.

Thirty-two patients were divided into Group 1 (n = 10), Group 2 (n = 11) and Group 3 (n = 11). A significant VAS improvement was observed in both SLIT groups, after the first and second pollen season, compared to baseline and to Group 3 (p < 0.05). Less symptoms and need for medications resulted during the second season (p < 0.05). No relevant variations in bronchial hyper-reactivity have been observed between the three groups. Only 2 patients experienced local or mild reactions in SLIT groups.

Both pre-seasonal and continuous regimen of SLIT with monomeric allergoid turned out effective and safe, suggesting that a pre-seasonal course with 5,000 AU/week for 10 weeks may represent a convenient option in patients with grass pollen allergic rhinitis with/without mild intermittent asthma. Further research is urgently needed to consolidate these preliminary evidences.