Figure 3. A two-step recruitment approach for clinical trials in preclinical Alzheimer’s disease using the mPACC as outcome measure.
a, conceptual framework of a sequential two-step recruitment strategy of a clinical trial in preclinical Alzheimer’s disease using a cognitive endpoint. b, the obtained sample size reduction using sample selection based on different percentiles (75th, 50th and 25th) of baseline plasma p-tau217 levels in step 1 followed by the selection based on the same percentiles (75th, 50th and 25th) of the Tau-PETMTL measurement in step 2 with mPACC5 as the primary endpoint. Note that 100% in step 2 refers to the participants selected by plasma p-tau217 in step 1. Errorbars represent the 95% CI. c shows the calculated sample size reductions for various plasma p-tau217 and Tau-PETMTL quartile combinations