Efficacy of grass pollen sublingual immunotherapy for three consecutive seasons and after cessation of treatment: the ECRIT study.

BACKGROUND

Data supporting a carry-over effect with sublingual immunotherapy (SLIT) are scarce. This randomized, double-blind, placebo-controlled study evaluated the efficacy, carry-over effect and safety of grass pollen SLIT using co-seasonal treatment.

METHODS

Patients (7.9-64.7 years) with grass pollen allergy received ultra-rush titration with increasing doses (30, 90, 150 and 300 IR) of a 5-grass pollen mixture every 20 min at the start of the pollen seasons, followed by 300 IR daily until the end of the pollen seasons. A baseline season (no SLIT) was followed by three consecutive treatment seasons and one follow-up season. Symptoms, medication and adverse events were documented and specific immunoglobulin (Ig)E and IgG(4) measured.

RESULTS

Data were analysed for 183 of the 213 randomized patients. Mean treatment duration varied between seasons (81.8-92.7 days). Combined scores (symptoms and medication) improved progressively across treatment seasons (up to 44.7% improvement for SLIT compared with baseline) and fluctuated between -11.3% and -14.8% for placebo (P < 0.05). Similar changes were observed for symptom scores, with a successive decrease of 39.7% (SLIT) and fluctuations between +13.6% and -1.51% for placebo (P < 0.05). Combined score (P = 0.0508) and symptom score improvements (P = 0.0144) with SLIT continued during follow up. Increases in specific IgG(4) observed in the first season were sustained for SLIT vs placebo throughout treatment (P = 0.0001). Titration and daily SLIT were well tolerated. No serious systemic or anaphylactic reactions were reported.

CONCLUSIONS

Seasonal SLIT with ultra-rush titration is well tolerated and effective from the first treatment season onwards. These data indicate a carry-over effect of seasonal SLIT.