Cow's milk oral immunotherapy in real life: 8-year long-term follow-up study

Oral immunotherapy (OIT) has been recognized as a promising treatment for severe and long-lasting cow's milk (CM) allergy. Once maintenance has been achieved, patients should maintain daily intake of CM to ensure desensitization. Clinical experience concerning long-term follow-up is scarce.

The authors aimed to assess long-term efficacy and safety of a maintenance phase of OIT in real life.

Prospective study of all children and adolescents, who underwent CM-OIT and were subsequently followed at our allergy center on maintenance dose (200 mL daily) for at least 36 months after reaching the maintenance phase (from 2009 to 2016).

Forty-two patients were enrolled: 60% male, 36% with history of anaphylaxis and 57% with asthma. The median time of follow-up was 69 months (range, 39-105 months) and the median age at the last clinical evaluation was 13 years (range, 6-23 years). Regarding adherence to the protocol: 92% are on free diet (at least 200 mL of CM daily; 7-g protein); 14% had transient interruptions and 7% definitely withdrawn with loss of tolerance. During maintenance, 45% developed mild to severe allergic reactions, and 7% had more than 3 episodes. A positive correlation between the occurrence of allergic reactions and history of anaphylaxis (p < 0.001) was found. The coexistence of asthma was risk factor for the occurrence of allergic reactions during maintenance.

This real-life study supports long-term efficacy and safety of CM-OIT. Despite daily intake, 41% had symptoms at some moment during the complete follow-up period; a total of 33 symptomatic days in patients with mean follow-up time of 67.5 months. Clinical tolerance depends on daily intake. The protective effect reached can be lost after CM withdrawal. History of anaphylaxis was a risk factor for the occurrence of allergic reactions during the maintenance phase.