HTT and Huntington disease: ASO-mediated HTT lowering has been successfully shown in murine HD models and holds a great promise for HD therapy.6,7 Infusion of siRNAs targeting HTT into the striatum of nonhuman primates has demonstrated significant silencing of HTT in a dose-dependent manner.8 However, it still needs to be determined if sufficient ASO and siRNA biodistribution, efficacy, and safety in the large animal and human brain can be achieved.