A PHASE II, RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED, DOSE-FINDING STUDY TO EVALUATE THE SAFETY, BIOMARKERS, AND EFFICACY OF TOMINERSEN IN INDIVIDUALS WITH PRODROMAL AND EARLY MANIFEST HUNTINGTON’S DISEASE

Key Inclusion Criteria -Huntington's disease (HD) gene expansion mutation carrier status with a CAP score of 400-500 inclusive Either:
*  Prodromal HD (defined as DCL 2 to 3, Independence Scale (IS) ⩾70, and ⩾TFC8); or
*  Early manifest HD (defined as DCL 4, Independence Scale (IS) ⩾70, and ⩾TFC8);
*  Total body weight \> 40 kg and a body mass index within the range of 18-32 kg/m2
*  Study Companion Key Exclusion Criteria
*  Current or previous use of an ASO (including small interfering RNA) or any HTT lowering therapy (including tominersen)
*  Anti-platelet or anticoagulant therapy within 14 days prior to screening or anticipated use during the study, including, but not limited to, aspirin (unless \*  History of gene therapy, cell transplantation, or brain surgery
*  Hydrocephalus
*  Pregnancy or breastfeeding, or intention of becoming pregnant during the study or within 5 months after the final dose of study drug
*  History of attempted suicide or suicidal ideation with plan (i.e., active suicidal ideation) that required hospital visit and/or change in level of care within 12 months prior to screening