Background: Alternaria alternata (AA) sensitisation is a common cause of respiratory allergies such as rhinitis and asthma. So far there are no controlled double-blind trials evaluating the efficacy and safety of specific sublingual immunotherapy (SLIT) in AA allergies.
Objective: To evaluate the efficacy of SLIT treatment in terms of clinical improvement and rescue medication usage in patients with confirmed AA respiratory allergy.
Subjects and methods: A randomised, parallel group study in 52 subjects was conducted (32 men, mean age 20 ± 9 years) with clinically- and laboratory-confirmed AA respiratory allergies (allergic rhinitis with or without mild-to-moderate asthma). Patients were randomly assigned to SLIT treatment (SLITone Alternaria, ALK-Abellò, Denmark) one vial per day without up-dosing for 3 consecutive years (n = 34) or to a control group (n = 18) with a random allocation ratio of 2:1. Clinical improvement was assessed by evaluating patient-reported outcome (PRO) using a 6 cm visual analogue scale (0: extreme worsening; 3: no change; 6: extreme improvement). The VAS score was evaluated every year with an intra- and inter-group comparison. Rescue medication score (MS) was assessed by evaluating symptomatic drug consumption.
Results: After 3 years the VAS score was 4.7 ± 0.8 in the SLIT group and 2 ± 1.6 in the control group (p = 0.0002). Clinical improvement was observed in 33 out of 34 subjects in the SLIT group (97%) and in 5 out of 18 in the control group (27%) (p = 0.0001; Fisher's exact test). The MS significantly (p = 0.0001) decreased in the SLIT group from 4.3 to 1.7 at the end of 3 years' treatment. In the control group MS increased from 3.4 to 4.0 by the end of the trial. No serious adverse events were observed in the either group. Six patients in the SLIT group (17%) reported side-effects, in general mild and transient. One patient prematurely discontinued the treatment due to gastrointestinal discomfort.
Conclusion: The current study has shown that a 3-year course of SLIT is efficacious and well-tolerated in subjects with AA respiratory allergies.