Fig. 1

Delphi study design. *Total number of questions asked. For some Likert scale questions, multiple options were given, with each analysed separately to assess consensus (e.g. “During the early stages of treatment, paediatric patients should be monitored for the types of symptoms listed below 1–2 times per year. Symptoms: Central and peripheral nervous system; Ocular system; Enterohepatic system; Cognitive performance [e.g. learning difficulties]; Cardiovascular system; Skeletal system; Pulmonary system”, where consensus was assessed separately for each symptom). †For each round, questionnaires were left open for responses in SurveyMonkey until analyses of the results began