Elevated Cow's Milk-Specific IgE Levels Prior to Oral Immunotherapy Decrease the Likelihood of Reaching the Maintenance Dose.

Background: Food desensitization via oral immunotherapy (OIT) is gaining acceptance in clinical practice. Owing to adverse reactions, the duration of the buildup phase until a maintenance dose is achieved may be prolonged, and in a minority of cases, OIT is stopped.

Objective: We aimed to assess factors associated with the probability of reaching the maintenance dose in cow's milk (CM) OIT.

Methods: We collected data from patients undergoing CM OIT at the Montreal Children's Hospital, BC Children's Hospital, and Hospital for Sick Children. We compared univariable and multivariable Cox regressions to evaluate sociodemographic factors, comorbidities, clinical characteristics, and biomarkers at study entry associated with the likelihood of reaching a maintenance dose of 200 mL of CM.

Results: Among 69 children who reached 4 mL of milk, the median age was 12 years (interquartile range, 9-15 years); 59% were male. Median duration of buildup phase from 4 to 200 mL was 24.0 weeks (interquartile range, 17.7-33.4 weeks). After adjusting for age and sex, higher baseline levels of specific IgE antibodies for α-lactalbumin (hazard ratio [HR] = 0.80; 95% confidence interval [CI], 0.67-0.95), β-lactoglobulin (HR = 0.86; 95% CI, 0.76-0.98), casein (HR = 0.82; 95% CI, 0.72-0.94), and total CM (HR = 0.79; 95% CI, 0.65-0.97) were associated with a decreased probability of reaching maintenance. In addition, for every 10-mL increase in CM tolerated at entry challenge, the probability of reaching maintenance increased by 10%.

Conclusions: The data suggest that higher levels of CM-specific IgE decreased the likelihood of reaching maintenance, whereas an increased cumulative CM dose at entry challenge increased the likelihood. Assessing these factors before therapy may assist in predicting the success of CM OIT.