This study is a continuation of a clinical trial NCT044155930 comparing the efficacy and safety of oral immunotherapy (OIT) with low or high doses of peanut protein (150 or 300 mg, respectively) and will involve patients who have accomplished their per-protocol participation in that trial.

The aim of current study is to assess a sustained unresponsiveness (SU) to allergen protein after at least 8 months of previously assigned high- or low-dose peanut OIT, followed by 4-week-allergen avoidance, and verified by an open oral food challenge (OOFC).

Oral immunotherapy is considered the most effective food allergy treatment. There are two main goals of food immunotherapy: achievement of desensitisation and sustained unresponsiveness. Desensitization is a temporary state of clinical non-reactivity which requires regular intake of allergen, whereas sustained unresponsiveness is defined as lack of clinical reaction to a food allergen after discontinuing OIT for a specific period of time.

The study is a continuation of a clinical trial NCT044155930, which was designed to compare the efficacy and safety of oral immunotherapy (OIT) with low or high doses of peanut protein (150 or 300 mg, respectively) in children with a confirmed diagnosis of peanut allergy. The participants of current study will be recruited from patients who have accomplished their per-protocol participation in previous trial.

Patients will receive the same maintenance dose of peanut allergen, which was used in previous trial (150 or 300 mg, respectively), for at least 8 months (32 weeks +/-2 weeks). Then, OIT will be discontinued for 4 weeks with strict peanut avoidance. After this period, an open oral food challenge (OOFC) will be performed to assess the achievement of sustained unresponsiveness.

Inclusion Criteria:

• patients who have accomplished their per-protocol participation in trial NCT044155930.
• signed Informed Consent by parent/legal guardian and patient aged>16 years old
• patient's/caregiver's cooperation with researcher

Exclusion Criteria:

• severe asthma

• uncontrolled mild/moderate asthma: forced expiratory volume at one second (FEV1)<80% (under 5 percentile), FEV1/forced vital capacity (FEV)<75% (under 5 percentile), hospitalization due to asthma exacerbation within last 12 months

• current oral/sublingual/subcutaneous immunotherapy with another allergen

• eosinophilic esophagitis

• allergic reaction of 4th or higher grade according to the World Allergy Organisation Systemic Allergic Reaction Grading System during immunotherapy

• a history of severe recurrent anaphylaxis episodes

• chronic diseases requiring continous treatment, including heart disease, epilepsy, metabolic disease, diabetes

• medication:

  • oral, daily steroid therapy exceeding 1 month within the last 12 months
  • at least two courses of oral steroid therapy (at least 7 days) within the last 12 months
  • oral steroid therapy longer than 7 days within the last 3 months
  • biological treatment
  • the need to constantly take antihistamines
  • therapy with b-blockers, angiotensin converting enzyme (ACE) inhibitors, calcium channel inhibitors

• pregnancy

• no consent to participate in the study

• lack of patient cooperation