N = 433 low-risk placebo, 1516 high-risk placebo, 1545 high risk pioglitazone. Average age, 73.1 years, 56.16% F, 96.6% White; average APOE ε4 carriage in the high-risk groups, 92.45%; MMSE mean baseline, 28.56. Outcome measure: Time to diagnosis of MCI due to AD for pioglitazone-treated subjects vs placebo in high-risk stratum. Pre-specified futility threshold, 30% conditional probability that a 40% treatment difference would be detected. The gene discussed is APOE; the disease is Alzheimer disease.