C9orf72 and frontotemporal dementia: A randomised, placebo-controlled Phase I/II clinical trial (NCT04931862) was also initiated to evaluate the safety, tolerability, and efficacy of the variant-selective, stereopure, phosphoryl guanidine backbone C9orf72-lowering ASO WVE-004 [90,91], in patients with ALS and/or FTD due to C9orf72 expansion.