Here's a report of a phase 1 clinical trial with a Morpholino oligo.
Komaki H, Nagata T, Saito T, Masuda S, Takeshita E, Tachimori H, Sasaki M, Takeda S. Exon 53 skipping of the dystrophin gene in patients with Duchenne muscular dystrophy by systemic administration of NS-065/NCNP-01: A phase 1, dose escalation, first-in-human study. Neuromuscular Disord. 2015;26(2)S261-2. doi:10.1016/j.nmd.2015.06.276
Antisense oligonucleotide-induced exon skipping, which is being studied for the treatment of Duchenne muscular dystrophy (DMD), allows synthesis of partially functional dystrophin. Patients amenable to exon 53 skipping form the second-largest population after patients amenable to exon 51 skipping. Therefore, in 2009, the National Center of Neurology and Psychiatry and Nippon Shinyaku Company collaborated to jointly develop an exon 53-skipping drug; an investigator-initiated clinical trial was started in June 2013 (NCT02081625) to examine the efficacy of NS-065/NCNP-01, a morpholino-based antisense oligonucleotide that facilitates skipping of exon 53 of the dystrophin gene.