Follow-on study of a multicentre randomised, controlled trial (PPOIT-003) evaluating the long-term safety and efficacy of Probiotic and Peanut Oral Immunotherapy (PPOIT) compared with Oral Immunotherapy (OIT) alone and with placebo in peanut allergic individuals

This is a multicentre follow-on study of the PPOIT-003 study (ACTRN12616000322437). There is no treatment intervention in this study. Although it is a follow -on study, PPOIT-003LT has been approved under a separate ethics submission. All participants who complete the PPOIT-003 will be eligible for enrolment into this follow-on study. Subjects and study staff will remain blinded to their PPOIT-003 treatment allocation and will continue with peanut avoidance or ingestion according to the instructions they received at the end of treatment in PPOIT-003 (based upon their treatment outcome at end of treatment in PPOIT-003). F0 (First visit): - The following assessments will be conducted: skin prick test, medical history review, blood and stool collection, Food Allergy Quality of Life questionnaire. F1 time point (12 months after F0 or 24 months after the final day of treatment) - phone call will be conducted for the following: - Allergy Questionnaire - Food Allergy Quality of Life questionnaire - Reminder for parent/participant to continue with diary recording (either mobile app or paper). F2 time point (24 months after F0 or 36 months after the final day of treatment) A visit will be conducted at this time point for the following: • Weight/height; • Skin prick test (peanut, egg, milk, cashew, almond, pistachio, hazelnut, dust mite and positive and negative control); • Blood and faecal sample (faecal sample collected by parents at home); • Anaphylaxis education; • Allergy questionnaire; • Food Allergy Quality of Life-Parent Form (FAQL-PF) and age appropriate Food Allergy Quality of Life forms (i.e. participants aged 8-12 years and 13-17 years to complete Food Allergy Quality of Life-Child Form (FAQLQ-CF) and Food Allergy Quality of Life-Teenager Form (FAQLQ-TF) respectively); Please note, in unavoidable circumstances (e.g. school camps), the window for the F2 time point can be +/- 14 days to accommodate parent/participant availability. Where a face-to-face visit is not possible, the visit will be conducted by phone and SPT, bloods and stool test will not be performed. F3 time point (36 months after F0 or 48 months after the final day of treatment) A visit will be conducted at this time point for the following: • Weight/height; • Skin prick test (peanut, egg, milk, cashew, almond, pistachio, hazelnut, dust mite and positive and negative control); • Blood and faecal sample (faecal sample collected by parents at home); • Anaphylaxis education; • Allergy questionnaire; • Food Allergy Quality of Life-Parent Form (FAQL-PF) and age appropriate Food Allergy Quality of Life forms (i.e. participants aged 8-12 years and 13-17 years to complete Food Allergy Quality of Life-Child Form (FAQLQ-CF) and Food Allergy Quality of Life-Teenager Form (FAQLQ-TF) respectively); • Medical history as clinically indicated prior to DBPCFC or OFC; • Double blind, placebo controlled food challenge (DBPCFC) or open OFC** for subjects with Sustained Unresponsiveness (SU) and Desensitisation (DS) without SU; • Double blind, placebo controlled food challenge (DBPCFC) or open OFC** for subjects with allergy if SPT <8mm and no recent immediate objective allergic reaction to peanut in the last 6 months; • Spirometry as clinically indicated before each DBPCFC or OFC A 2nd DBPCFC or OFC will be performed for DS without SU subjects if they pass the 1st F3 DBPCFC or OFC. These subjects will commence an 8-week period of peanut elimination after passing the first F3 DBPCFC or OFC, after which they will undergo a 2nd DBPCFC or OFC to assess for conversion to SU. The 2nd DBPCFC or OFC must be a minimum of 8 weeks post the 1st F3 challenge part A. If the 1st DBPCFC or OFC is conducted more than 3 months after the F3 visit (for those who had the F3 visit prior to the protocol amendment (version 5), a repeat skin prick test and blood collection will be performed for the subject. **The decision for DBPCFC or open OFC is at the discretion of the site investigator The window for the F3 timepoint DBPCFC or OFC can be +/- 6 months (from 3.5 to 4.5 years post-treatment) to accommodate parent/participant availability. Where a face-to-face visit is not possible, the visit will be conducted by phone and SPT, bloods and stool test will not be performed. F4 time point (48 months after F0 or 60 months after the final day of treatment) A visit will be conducted at this time point for the following: • Weight/height; • Skin prick test (peanut, egg, milk, cashew, almond, pistachio, hazelnut, dust mite and positive and negative control); • Blood and faecal sample (faecal sample collected by parents at home); • Anaphylaxis education; • Allergy questionnaire; • Food Allergy Quality of Life-Parent Form (FAQL-PF), parental burden form (FAQL-PB) and age appropriate Food Allergy Quality of Life forms (i.e. participants aged 8-12 years and 13-17 years to complete Food Allergy Quality of Life-Child Form (FAQLQ-CF) and Food Allergy Quality of Life-Teenager Form (FAQLQ-TF) respectively); • Medical history as clinically indicated prior to DBPCFC or OFC; •Double blind, placebo controlled food challenge (DBPCFC) or open OFC** for all subjects (SU, DS without SU and allergic) – only if this was not performed at F3 with clinical outcome determined; • Spirometry as clinically indicated before each DBPCFC or open OFC A 2nd DBPCFC/OFC will be performed for DS without SU subjects if they pass the 1st F4 DBPCFC/OFC. These subjects will commence an 8-week period of peanut elimination after passing the 1st F4 DBPCFC/OFC, after which they will undergo a 2nd DBPCFC/OFC to assess for conversion to SU. The 2nd DBPCFC/OFC must be a minimum of 8 weeks post the 1st F4 DBPCFC part A or 1st F4 OFC. The procedures performed for the 2nd F4 DBPCFC/OFC will be similar to the 1st F4 DBPCFC/OFC (including repeat SPT, blood and stool sample collection and questionnaires). If the DBPCFC/OFC is conducted more than 3 months after the F4 visit (for those who had the F4 visit prior to the protocol amendment (version 5 or earlier), a repeat skin prick test and blood collection will be performed for the subject. **The decision for DBPCFC or open OFC is at the discretion of the site investigator The window for the F4 timepoint DBPCFC/OFC can be +/- 6 months (from 4.5 to 5.5 years post-treatment) to accommodate parent/participant availability. NOTE: Where a face-to-face visit is not possible, the visit will be conducted by phone and SPT, bloods and stool test will not be performed. ***PPOIT-003 study participants who did not enrol in PPOIT-003LT will be invited back to complete a food challenge at the F4 timepoint. A PPOIT-003LT protocol ADDENDUM for participants who are currently not in the follow-on study and who will be invited for a long-term DBPCFC/OFC at the F4 timepoint (60 months post-treatment). These participants will not be required to complete a F5 visit. F5 time point (60 months after F0 or 72 months after the final day of treatment) A visit will be conducted at this time point for the following: • Weight/height; • Skin prick test (peanut, egg, milk, cashew, almond, pistachio, hazelnut, dust mite and positive and negative control); • Blood and faecal sample (faecal sample collected by parents at home); • Anaphylaxis education; • Allergy questionnaire; • Food Allergy Quality of Life-Parent Form (FAQL-PF), parental burden form (FAQL-PB), and age appropriate Food Allergy Quality of Life forms (i.e. participants aged 8-12 years and 13-17 years to complete Food Allergy Quality of Life-Child Form (FAQLQ-CF) and Food Allergy Quality of Life-Teenager Form (FAQLQ-TF) respectively); • Spirometry (all children over 8 years) As this is the final study visit, the window for the F5 time point can be +/- 6 months to accommodate parent/participant availability Where a face-to-face visit is not possible, the visit will be conducted by phone and SPT, bloods and stool test will not be performed. - This is the end point of the follow on study and participants will return to their Clinical Allergist for ongoing clinical care.