Statistical Considerations When Building upon an Existing Randomized Trial

The original LEAP (Learning Early About Peanut allergy) trial was a randomized controlled trial (RCT) that investigated whether the early introduction of peanut-based foods reduced the development of peanut allergies among high-risk children.1 The LEAP trial followed children from infancy to 5 years of age. The LEAP-Trio study (ClinicalTrials.gov identifier, NCT03546413), published in this issue of NEJM Evidence, builds upon the earlier RCT to explore longer-term outcomes.2 In the LEAP-Trio study, the authors report on allergy rates in a subset of the original study cohort, now that the children have reached 12 years of age.