Introduction
Peanut allergy persists for life in the majority of patients1,2. Current management relies on strict allergen avoidance; however, up to 50% of peanut allergic patients have accidental exposures within 1 year3. Moreover, allergic reactions to peanut can be severe, and account for 30% of food anaphylaxis deaths4. There is an unmet need for a treatment that induces long-lasting remission of peanut allergy and improves health-related quality of life (HRQL).
In clinical trials, patient-reported outcomes, such as HRQL, are vital to understand the patient perspective and experience since they capture perceived benefits of treatment not captured by other endpoints. Regulatory agencies increasingly require these data as part of their evaluation process5. In drug trials, HRQL is generally only assessed at baseline and at treatment completion; yet assessment of HRQL beyond the treatment phase is needed to ascertain whether benefits are sustained over a longer time period6.
Peanut OIT is effective at inducing desensitization and can induce sustained unresponsiveness (SU) in a subset of treated patients, however there is a paucity of data on long-term effectiveness7,8 and impact on HRQL. Few studies have evaluated for long-term SU following peanut OIT; these suggest that OIT-induced SU may be short-lived, with up to 67% of treatment responders losing their SU status within 12-months7,8. A meta-analysis of peanut OIT studies found that peanut OIT was associated with frequent adverse events and did not lead to significant improvement in HRQL9. Further research to identify novel approaches that improve the efficacy and safety of OIT are needed.
A combined probiotic and peanut oral immunotherapy (PPOIT) treatment was shown to induce desensitization (83.9%) and 2-6 week SU (74.2%) after 18-months of treatment in a Phase 2a randomized control trial (PPOIT-001 study; ACTRN 12608000594325)10. Long-term follow-up of patients showed that PPOIT-induced SU persisted to 4-years post-treatment in 70% of initial treatment responders11. PPOIT treatment also resulted in improved HRQL compared with placebo, with improvement specifically related to the attainment of SU12. Weaknesses of the Phase 2a study included the selection of subjects with peanut allergy based upon a clinical history of reaction and positive peanut skin prick test (SPT) or specific-IgE (sIgE) rather than double-blind placebo-controlled food challenge (DBPCFC) and assessment of SU at 2-6 weeks post-treatment rather than a longer period after treatment.
This study aimed to confirm previous findings using a more stringent 8-week post-treatment SU test in children aged 1-12 years with challenge-confirmed peanut allergy. Safety, HRQL and long-term outcomes were also evaluated.