Clinical Bioavailability of the Novel BACE1 Inhibitor Lanabecestat (AZD3293): Assessment of Tablet Formulations Versus an Oral Solution and the Impact of Gastric pH on Pharmacokinetics

The relative bioavailability of lanabecestat administered as 2 tablet formulations versus an oral solution was investigated. This phase 1 single-center, open-label, randomized, 3-period crossover study involved healthy male and nonfertile female subjects aged 18-55 years (NCT02039180). Subjects received a single 50-mg lanabecestat dose as solution, tablet A, or tablet B on day 1 of each crossover period; 14 of 16 subjects completed the study. Relative bioavailability based on plasma lanabecestat AUC(0-infinity) (area under the plasma drug concentration-time curve from zero to infinity) geometric mean ratio versus oral solution (primary variable) was: tablet A,1.052 (90% confidence interval [CI], 1.001-1.106); tablet B,1.040 (0.989-1.093). These 90%CIs for geometric mean ratios are within accepted standard bioequivalence boundaries for all other pharmacokinetic (PK) parameters for both lanabecestat and metabolite (AZ13569724). All 3 formulations had similar plasma lanabecestat concentration-time profiles. Six adverse events were reported by 6 subjects (37.5%, all mild). GastroPlus modeling predicted a negligible impact of gastric pH changes on systemic PK (up to pH 7.4). Both tablet formulations fall within standard accepted bioequivalence criteria versus the oral solution. A single 50-mg lanabecestat dose was well tolerated as a solution or tablet formulation in this population.