The step-down approach in children with cow's milk allergy: Results of a randomized controlled trial.

Background: The Step-Down Approach for Cow's Milk Allergy (SDACMA) trial evaluated the tolerability and the rate of immune tolerance acquisition in CMA children starting dietary treatment with amino acid-based formula (AAF) and then switching to EHCF containing the probiotic Lacticaseibacillus  rhamnosus GG (EHCF + LGG).

Methods: Randomized controlled trial involving IgE-mediated CMA children receiving AAF from at least 4 weeks. EHCF + LGG tolerance was evaluated by the results of double-blind placebo-controlled food challenge (DBPCFC). Subjects tolerating EHCF + LGG were randomly allocated to remain on AAF, or to switch to EHCF + LGG. Immune tolerance acquisition to cow's milk proteins was evaluated with DBPCFC after 12 months of treatment. Allergy screening tests and body growth were also monitored.

Results: Sixty IgE-mediated CMA children were enrolled. The proportion of children treated with AAF who resulted tolerant to the first exposure of EHCF + LGG was 0.98 (exact 95% CI 0.91-0.99). The rate of the immune tolerance acquisition to cow milk proteins after 12 months treatment was higher in the EHCF + LGG (0.48, 95% exact CI 0.29-0.67, n/N = 14/29) than in the AAF group (0.03, 95% exact CI 0.001-0.17, n/N = 1/30). There was an absolute benefit increase (ABI) of tolerance rate equal to 0.45 (95% CI 0.23-0.63, Newcombe method 10) for EHCF + LGG versus AAF, corresponding to a NNT of 2 (2-4, Bender's method). A normal body growth pattern was observed in the two study groups.

Conclusion: In IgE-mediated CMA children the step-down from AAF to EHCF + LGG is well tolerated and could facilitate the immune tolerance acquisition.