Abstract LRRK2 (encoding leucine-rich repeat kinase 2) variants are the most common genetic cause of Parkinson’s disease (PD). Lowering LRRK2 levels and/or inhibiting LRRK2 activity may modify PD-associated neuropathology. BIIB094 (ION859), an antisense oligonucleotide, targets LRRK2 mRNA for degradation. REASON was a first-in-human randomized phase 1 study investigating the safety, tolerability, ...