Abstract
BACKGROUND: The optimal dose of grass pollen tablets for sublingual immunotherapy (SLIT) in allergic rhinoconjunctivitis patients was previously established in a multinational, randomized, double-blind, placebo-controlled study in 628 adults. Patients were randomized to receive once-daily 5-grass pollen sublingual tablets of 100 IR (index of reactivity), 300 IR or 500 IR, or placebo starting 4 months before the pollen season. OBJECTIVE: The aim of this complementary analysis was to determine whether 300 IR 5-grass pollen SLIT-tablets is effective in different subtypes of patients who are allergic to grass pollen. METHODS: Different subgroups could be identified regarding comorbidities (with or without asthma during the grass-pollen season), sensitization (mono/polysensitization) and symptom severity. An additional exploratory analysis was performed within four subgroups based on pre-treatment assessment: Group 1=high specific IgE; Group 2=high symptom scores; Group 3=high skin sensitivity; Group 4=any of Group 1, 2 or 3. RESULTS: Asthma and sensitization status were not significant covariates as the average Rhinoconjunctivitis Total Symptom Score (RTSS) was identical for patients with and without grass-pollen asthma, as well as for mono- and polysensitized patients. Across the four subgroups, average RTSSs (+/- SD) for the optimal dosage (300 IR) were 3.91 +/- 3.16, 3.83 +/- 3.14, 2.55 +/- 2.13 and 3.61 +/- 2.97, for subgroups 1, 2, 3 and 4, respectively. ANCOVA showed that in Group 1 average RTSS did not differ significantly with different doses of SLIT. In Groups 2, 3 and 4, doses of 300 IR and 500 IR were significantly more effective than 100 IR and placebo (P< or =0.035). All doses of SLIT administered in this study can be considered safe in the patients investigated. CONCLUSIONS: The risk-benefit ratio validates the use of 300 IR tablets in clinical practice in all of these patient subgroups, regardless of severity profile, sensitization status and presence of asthma.