A Phase 1/2, Randomized, Sequential, Dose-Escalation Study to Evaluate the Safety, Tolerability, and Efficacy of a One-Time, Bilateral, Intraparenchymal Infusion of SPK-10001 Into the Caudate and Putamen in Participants With Huntington's Disease

Key Inclusion Criteria: * Have confirmed huntingtin (HTT) cytosine-adenine-guanine (CAG) repeat length ≥40 on genetic testing and confirmation diagnostic test by the central laboratory (CL) at screening. * Have striatal atrophy demonstrated by caudate/intracranial volume less than the age-adjusted cutoff values associated with HDISS Stage 1. * Have UHDRS Total Motor Score (TMS) equal to or greater than the age-adjusted cutoff value associated with HDISS Stage 2. * Have UHDRS Total Functional Capacity (TFC) greater than or equal to 11. * Use of cholinesterase inhibitors, memantine, amantadine,…