Failure of C9orf72 sense repeat-targeting antisense oligonucleotides: lessons learned and the path forward

The recent failure of two independent clinical trials targeting C9orf72 sense repeat-containing RNAs with antisense oligonucleotides was a great disappointment for the field. Cammack et al. discuss the data from these trials, possible reasons for the failures, and the future of C9orf72 therapeutic targeting moving forward.