Direct comparison between continuous and coseasonal regimen for sublingual immunotherapy in children with grass allergy: a randomized controlled study

BACKGROUND: Pre-seasonal, pre-coseasonal and continuous regimens of immunotherapy
have been proposed, but their efficacy was never compared. This phase IV open
study was designed to compare the clinical efficacy of a continuous and a
coseasonal sublingual immunotherapy (SLIT) for grass allergy over 3 years.
METHODS: Children with rhinitis/asthma because of grass were randomized to SLIT
given continuously (all year long) or coseasonally. The treatment started in
October 2005 in the continuous SLIT group and in March 2006 in the coseasonal
group Diary cards for clinical symptoms (from 0 = none to 3 = severe), and drug
intake were recorded form March to June in 2005 (baseline), 2006 2007, and 2008.
Specific IgE and IgG4 were evaluated every year.
RESULTS: Eighty children (age range 8-16) were randomized and 72 completed the
study. In the first year, the symptom + medication score improved by 44% in the
continuous group and by 20% in the coseasonal group (p = 0.04). Symptoms, chest
symptoms, and drug intake separately showed a greater decrease vs. baseline in
the continuous group. In the second year, the global score decreased in both
groups with no significant difference, whereas symptom score decreased more in
the continuous group. In the 3rd year, there was no difference in clinical
parameters between the two groups. Specific IgG4 were significantly higher vs.
baseline since the 1st year in the continuous group and since the 2nd in the
coseasonal group.
CONCLUSION: In grass pollen allergy, the continuous regimen performs better than
the coseasonal in the first season, whereas in the subsequent years, the two
regimens are nearly equivalent.