S56AptAmers gov: NCT02081625). The NS-065/NCNP-01 is a morpholino based antisense oligonucleotide that has been developed to skip the exon 53 of the dystrophin gene and to treat DMD patient amenable to the exon 53 skipping. It has been confirmed potent efficacy and high safety in pre-clinical studies. This clinical trial is an exploratory phase 1, single-site, first-in-human study. The primary endpoints are the safety and tolerability and the secondary endpoints are the pharmacokinetics and efficacies (dystrophin recovery). Three doses cohort design (1.25 mg/kg, 5 mg/kg and 20 mg/kg) was adopted and all subjects were dosed weekly intravenous infusion for 12 weeks. Mainly nonambulant subjects were recruited because the dose and duration in this trial was not enough to expect functional improvement. Of total 10 subjects, each three subjects were randomly assigned to 1.25 mg/ kg or 5 mg/kg cohorts, and four subjects were assigned to 20 mg/ kg cohort. An in vitro confirmation of dystrophin recovery and exon 53 skipping in subject-derived cells was one of inclusion criteria. Subject's mutations were classified into any of exons 45-52, 48-52 or 49-52 deletion; all NS-065/NCNP-01 treated cells satisfied the criteria. One week after an initial dosing for the first subject in each cohort, next subjects were dosed. Safety review committee advised the principal investigator whether or not to proceed to next cohort. At the end of 2014, dosing to all subjects had completed; no serious adverse events were observed. Dystrophin expression is to be evaluated by Western blotting and immunofluorescent staining. The analysis is still ongoing, but an immunofluorescent image analysis will be performed as objective and quantitative as possible by automated measurements. We would report progress of the first-in-human study of NS-065/ NCNP-01; the morpholino based exon 53 skipping drug for DMD.