Phase 1/1b Studies of UCB0599, an Oral Inhibitor of alpha-Synuclein Misfolding, Including a Randomized Study in Parkinson's Disease

Background: Parkinson's disease (PD) and its progression are thought to be caused and driven by misfolding of alpha-synuclein (ASYN). UCB0599 is an oral, small-molecule inhibitor of ASYN misfolding, aimed at slowing disease progression. Objective: The aim was to investigate safety/tolerability and pharmacokinetics (PK) of single and multiple doses of UCB0599. Methods: Safety/tolerability and PK of single and multiple doses of UCB0599 and its metabolites were investigated in two phase 1 studies in healthy participants (HPs), where food effect and possible interaction with itraconazole (ITZ) were assessed (UP0030 [randomized, placebo-controlled, dose-escalation, crossover study, N = 65] and UP0078 [open-label study, N = 22]). Safety/tolerability and multi-dose PK of UCB0599 were subsequently investigated in a phase 1b randomized, double-blind, placebo-controlled study of participants with PD (UP0077 [NCT04875962], N = 31). Results: Across all studies, UCB0599 displayed rapid absorption with linear, time-independent PK properties; PK of multiple doses of UCB0599 were predictable from single-dose exposures. No notable food-effect was observed; co-administration with ITZ affected UCB0599 disposition (maximum plasma concentration and area under the curve increased similar to 1.3- and similar to 2 to 3-fold, respectively) however, this did not impact the safety profile. Hypersensitivity reactions were reported in UP0030 (n = 2) and UP0077 (n = 2). Treatment-related adverse events occurred in 43% (UCB0599), and 30% (placebo) of participants with PD were predominantly mild-to-moderate in intensity and were not dose related. Conclusions: Seventy-three HPs and 21 participants with PD received UCB0599 doses; an acceptable safety/tolerability profile and predictable PK support continued development of UCB0599 for the slowing of PD progression. A phase 2 study in early-stage PD is underway (NCT04658186). (C) 2022 UCB Pharma. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.