The exon-skipping treatment golodirsen (Vyondys 53) is safe and effective in the long term in ambulatory patients with Duchenne muscular dystrophy (DMD), according to results of a phase 1/2 clinical trial published in the journal Nucleic Acid Therapeutics.

“The data hold promise for functional benefits of golodirsen, warranting larger studies,” Laurent Servais, MD, PhD, and the coauthors of the study wrote.

The aim of the first-in-human, multicenter, 2-part, open-label study was to assess the clinical safety and efficacy of the treatment in the long-term in patients amenable to exon 53 skipping. This 2-part study was comprised of a 12-week, randomized, double-blind, placebo-controlled, dose-titration portion followed by a 9-week safety review in part 1 and a 168-week, open-label portion evaluating the effect of golodirsen at a dose of 30 mg/kg.

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The study recruited 39 participants, aged 6 to 15 years, with DMD amenable to exon 53 skipping who were still able to walk. The locations were in the US, France, Italy, and the UK. 

The results showed that golodirsen treatment increased the level of dystrophin protein 16-fold compared to placebo.

The 6-Minute Walk Distance test decreased by 99 m in patients treated with golodirsen at the end of 3 years while it decreased by 181.4 m in external controls. In this time period, 9% of patients lost the ability to walk compared to 26% of the external controls. 

The forced vital capacity declined by 8.4% in patients treated with golodirsen. This was a value comparing favorably with rates reported in the literature. 

“This study provides evidence for golodirsen biologic activity and long-term safety in a declining DMD population and suggests functional benefit versus external controls,“ the researchers concluded.


Servais L, Mercuri E, Straub V, et al. Long-term safety and efficacy data of golodirsen in ambulatory patients with Duchenne muscular dystrophy amenable to exon 53 skipping: a first-in-human, multicenter, two-part, open-label, phase 1/2 trial. Nucleic Acid Ther. Published online November 17, 2021. doi:10.1089/nat.2021.0043

Phase I/II study of SRP-4053 in DMD patients. US National Library of Medicine. Last updated October 19, 2020. Accessed November 29, 2021.