BACE1 and Alzheimer disease: Meanwhile, unlike GRL-8234, other BACE1 inhibitor drugs tested to date have poor or no selectivity for BACE1 over its homolog BACE2 (up to ~3 folds) and their clinical trials at symptomatic AD stages were halted because of futility or adverse effects including cognitive worsening at the highest dosage (Imbimbo and Watling, 2019; McDade et al., 2021; Bazzari and Bazzari, 2022).