The USFDA approved casimersen injection (an antisense oligonucleotide) for Duchenne muscular dystrophy (DMD) treatment on 25th February, 2021. Thereafter, the patients with an established mutation of the DMD gene susceptible to exon 45 skipping can benefit from this first of a kind targeted treatment. This approval was in accordance with the rise in dystrophin (a protein that maintains the integrity of the muscle cells) production in skeletal muscle in DMD patients on this treatment.

DMD, one of the most common type of muscular dystrophy is a rare genetic disease marked which causes weakness and muscle deterioration which worsen with time. First symptoms are commonly observed between 3- 5 years of age. Being a rare occurrence in females, DMD affects roughly 1 out of every 3,600 male infants.

The approval was based on a randomized controlled study comprising of 43 patients (aged 7-20 years of age, all males) with unusual DMD Mutation. These patients received either casimersen 30 mg/kg intravenously or placebo. Compared with placebo, the patients on casimersen injection portrayed greater increase in dystrophin protein levels from initiation to week 48. The clinical advantage of this injection is most likely due to the increase in dystrophin production in patients with DMD who have established mutation of the dystrophin gene amenable to exon 45 skipping, FDA deduced.

DMD patients frequently reported adverse effects- throat pain, cough, fever, joint pain, upper respiratory tract infections and headache.

Although the clinical studies did not portray kidney toxicity with the use of casimersen injection, but it was observed in the nonclinical studies. Therefore, kidney function should be tracked in patients on casimersen injection therapy.

The casimersen injection was approved via the Accelerated Approval pathway; future study is needed to confirm its clinical benefits. Presently, clinical study designed to examine its safety and efficacy in ambulatory patients with DMD in under process.