Duchenne muscular dystrophy (DMD) patients treated with eteplirsen (Exondys 51) showed improved ambulatory and pulmonary function over 7 years of follow-up, researchers reported in the Journal of Neuromuscular Diseases.

Mitelman et al found that eteplirsen-treated patients had a longer median time to loss of ambulation compared to external controls (5.09 vs 3.00 years, P <.01).

This delay of 2.1 years in loss of ambulation predicts a delay in reaching subsequent disease milestones, such as the loss of motor abilities, development of scoliosis, peak forced vital capacity, need for supportive ventilation, forced vital capacity of 1L, and death.

In addition, eteplirsen-treated DMD patients presented with attenuated rates of pulmonary decline compared to controls, measured by percent-predicted forced vital capacity (-3.3 vs -6.0 percentage points annually, P <.0001).

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Overall, this study shows that eteplirsen delays disease progression in DMD patients based on up to 7 years of treatment, and corroborates previous findings from the first 4 years of treatment.

The study team pointed to the length of follow-up time for patients with DMD as a strength of their study. “With 5.7 years on average for all patients included in Studies 201/202/405 (range: 4.13 to 6.88) and most patients having >6 years of follow-up, this study describes the longest follow-up of eteplirsen-treated patients to date,” they said.

This study included 12 eteplirsen-treated patients (mean age, 9.48 ± 1.18 years) from 3 studies and 71 external control patients (mean age, 8.60 ± 2.09 years) from 3 different databases.

DMD is a rare disease and, therefore, clinical trial and real-world data are scarce. However, understanding the long-term efficacy of eteplirsen in patients with DMD is important for improving clinical management of the disease.


Mitelman O, Abdel-Hamid HZ, Byrne BJ, et al. A combined prospective and retrospective comparison of long-term functional outcomes suggests delayed loss of ambulation and pulmonary decline with long-term eteplirsen treatment. J Neuromuscul Dis. Published online August 19, 2021. doi:10.3233/JND-210665