Abstract Background A number of extended families in Colombia with early‐onset ADAD have a PSEN1 mutation at codon 280 (E280A), comprise the largest ADAD kindred in the world. Trial participants have been treated with crenezumab (an experimental anti‐amyloid monoclonal antibody) or placebo. Topline results were presented in August, 2022 at AAIC. Although the trial did not demonstrate a statistically significant clinical benefit in either of its co‐primary endpoints, multiple statistical innovations were incorporated into this trial. Method The API ADAD Colombia trial is a randomized, double‐blind, placebo‐controlled, parallel‐group phase 2b study evaluating the efficacy, safety, and tolerability of crenezumab in cognitively unimpaired ADAD PSEN1 E280A mutation carriers in Colombia (NCT01998841). Due to under enrollment and concerns with the sensitivity of the primary endpoint, the protocol was amended mid‐trial to change from 260 weeks of treatment to a common‐close design whereby treatment continued in the double‐blind portion until the last enrolled participant received 260 weeks of treatment. Because of the change in trial design and power considerations, the primary analysis was adapted from a traditional mixed model with repeated measures (MMRM) based analysis to a random coefficient regression model (RCRM) based analysis. To quantitatively examine the adequacy of the RCRM assumptions, a robust variance estimator (Huber 1967; White 1982) was prespecified as a sensitivity analysis to calculate the standard errors and p‐values of the co‐primary endpoints. This study used a type‐I‐error‐controlled statistical procedure to identify and elevate the Free and Cued Selective Reminding Test (FCSRT) cueing index to a co‐primary endpoint. To comprehensively assess the crenezumab effect across primary and secondary endpoints, the prespecified relative reduction point estimates along with the bootstrapped 95% confidence intervals were generated. Result Innovative statistical methods in this trial will be presented. Conclusion Although the API Colombia study did not meet its co‐primary endpoints, statistical learnings from this trial can benefit development of future AD trials. To further maximize the value of this unique trial dataset, participant‐level data will be made publicly available, including clinical, imaging, and biomarker data. Funding: NIA grants RF1‐AG041705, R01‐AG055444, Genentech, Roche, philanthropic contributions to Banner Alzheimer’s Foundation. FlorbetapirPET was partly supported by Avid and Lilly.