Single‐ and Multiple‐Dose Safety, Tolerability, and Pharmacokinetic Profiles of ASP8062: Results From 2 Phase 1 Studies

ASP8062 is an orally active γ‐amino‐butyric acid type B (GABA B ) receptor positive allosteric modulator currently in phase 2 development. Safety and pharmacokinetic (PK) profiles of ASP8062 were evaluated in 2 studies in healthy subjects. The first study (a first‐in‐human study) evaluated single ascending doses (SAD) of ASP8062. The second study was composed of 2 parts: part 1 evaluated multiple ascending doses (MAD) of ASP8062 for 14 days, and part 2 was a single‐dose arm to assess the PK of ASP8062 in cerebrospinal fluid (CSF). Fifty‐six men (SAD) and 56 subjects (24 women and 32 men; MAD) were enrolled. Across the SAD dosing range, area under the concentration‐time curve was dose proportional; increases in maximum plasma concentration appeared linear but were slightly less than dose proportional. Time to maximal concentration and half‐life were 1‐4 hours and ∼40‐50 hours, respectively; no food effect was observed. ASP8062 PK properties at steady state were similar to those following a single dose. Steady state was achieved by ∼day 9 with ∼2‐fold accumulation, and ASP8062 was detected in CSF. ASP8062 was well tolerated; no clear evidence of ASP8062's effects on safety, cognition, drug withdrawal, or suicidal ideation/behavior was observed. These data support the development of ASP8062 in indications where the GABA B receptor is a target.