75 Efficacy of Slow Oral Immunotherapy for Cow's Milk Allergy

BACKGROUND: Efficacy and safety of slow oral immunotherapy (SOIT) is not yet clear, especially regarding tolerance acquisition. METHODS: We recruited 32 cow's milk (CM) allergy confirmed by oral food challenge (OFC). Twenty-five subjects were enrolled as SOIT group, and remaining 7 were as control. The inclusion criteria were as follows; (1) CM allergy without anaphylaxis confirmed by OFC just before the trial, and (2) children >4 years. In SOIT group, they were asked to take small amount of CM at home after the OFC. The initial dose was about 1/4 of the threshold eliciting positive objective symptoms, and it was built up to 200 mL CM depends on the symptoms (build up phase). After reaching 200 mL, they were asked to take 200 mL CM daily until the asymptomatic duration lasting for more than 3m (maintenance phase). The subjects, who completed maintenance phase, underwent OFC to confirm the tolerance acquisition after the cessation of CM ingestion for 2w (confirm-OFC). In control group, they had eliminated CM completely and underwent the confirm-OFC after 9.8 ± 2.9 m (mean ± SD). We investigated the endpoints (adverse reactions, medical treatments, results of confirm-OFC, and laboratory findings), prospectively. RESULTS: In SOIT group (n = 25) and control group (n = 7), the average age was 6.6y and 4.7y, respectively. The average threshold was 52 mL and 17 mL, and the CM specific IgE was 17.6 Ua/mL/9.9 Ua/mL, respectively. The average period of build up and maintenance phases in SOIT group was 80d (n = 25) and 98d (n = 15), respectively. The frequency of adverse reactions in all of build up (1973d) and maintenance phases (2924d) were 13.5% (mild symptoms)/2.3% (moderate symptoms) and 1.7% (mild)/0.3% (moderate), respectively. No patient had administered adrenaline during SOIT. Fifteen subjects in SOIT and 7 in control underwent the confirm-OFC. In SOIT, 8 subjects (53.3%) passed the confirm-OFC, whereas 2 (28.6%) passed in control. There was no statistically significant difference regarding tolerance acquisition between these 2 groups (P = 0.277). CONCLUSIONS: This study suggests that SOIT for about 1/2 year induces desensitization effectively for CM allergy without severe adverse reactions. Further and longer study would be required to prove accelerated tolerance acquisition by SOIT.