Skipping Multiple Exons to Treat DMD-Promises and Challenges

Area of Science:

• Biochemistry
• Genetics
• Pharmacology

Background:

• Duchenne muscular dystrophy (DMD) is a fatal genetic disorder caused by mutations in the DMD gene.
• Antisense-mediated exon skipping is a therapeutic strategy using synthetic nucleic acids to restore the reading frame and enable functional protein expression.
• Eteplirsen, approved in 2016, skips DMD exon 51, benefiting approximately 13% of DMD patients.

Purpose of the Study:

• To explore the potential of multiple exon skipping using cocktail antisense oligonucleotides (AOs) for treating Duchenne muscular dystrophy.
• To address the challenges posed by current drug approval systems for cocktail AO therapies.

Main Methods:

• Demonstration of multiple exon skipping in animal models (dystrophic mice and dogs) using cocktail antisense oligonucleotides (AOs).
• Analysis of the therapeutic effect of cocktail AOs targeting multiple exons simultaneously.

Main Results:

• Multiple exon skipping is theoretically applicable to 80-90% of DMD patients.
• Cocktail AOs have shown promise in animal models for achieving therapeutic effects not possible with single AOs.
• The efficacy of cocktail AOs relies on the combined effect of multiple AOs, where individual AOs may not be therapeutic on their own.

Conclusions:

• Cocktail antisense oligonucleotide (AO) therapy holds significant potential for treating a larger proportion of Duchenne muscular dystrophy patients.
• Current drug approval systems are not designed to evaluate the unique therapeutic mechanism of cocktail AO therapies.
• Adaptations in the drug approval process are necessary to facilitate the development and accessibility of cocktail AO treatments for DMD.