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Preliminary results of the RACER53 Phase 3 study for boys with Duchenne muscular dystrophy

28 May 2024

On Monday 27 May 2024, NS Pharma announced the preliminary results of the RACER53 Phase 3 clinical trial. This randomised, placebo-controlled, double-blind comparative study aims to assess if viltolarsen is safe and effective for use in boys with Duchenne muscular dystrophy (DMD).

What was the study for?

Viltolarsen, also known under the brand name VILTEPSO, is an exon-skipping therapy for people with DMD who have a genetic change in the dystrophin gene that is responsive to exon 53 skipping.

The preliminary results show the study failed to achieve its primary objective (also known as endpoint), which was to demonstrate a significant difference in time-to-stand following VILTEPSO treatment, compared to the control group.

There were no new safety concerns raised during this part of the study, with side-effects reported being mild to moderate.

The study involved 77 boys with DMD who can walk unassisted. They were dosed once a week over 48 weeks.

What does this mean for people in the UK?

In 2020, VILTEPSO received accelerated approval by the Food and Drug Administration (FDA) in the United States. The approval was based on the increased levels of dystrophin in skeletal muscle (muscles that help us move and breathe) of the treated boys. The health authority in the UK responsible for issuing marketing authorisations (the licence) for medicines is the Medicines & Healthcare Products Regulatory Agency (MHRA), not the FDA. It is not currently known how this will affect any future approval of VILTEPSO in the UK and Europe, but we will make sure to provide you any updates in the process.

Duchenne muscular dystrophy is a rare muscle-wasting condition that mainly affects boys and men. People with Duchenne lack a protein called dystrophin, which is required to maintain the strength of muscles.

Read more about it in the NS Pharma press release here.

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