Sarepta Therapeutics has announced the completion of the ESSENCE trial – a global Phase 3 study on Duchenne muscular dystrophy patients with the U.S. FDA-approved treatments AMONDYS 45 (casimersen) and VYONDYS 53 (golodirsen).
This study examined 225 patients and continued over a nine-year period. Treated patients showed a potential decrease in disease symptoms. Sarepta will submit the full results from the ESSENCE study to the U.S. FDA.
According to Sarepta, the trial did not meet its primary goal: significant increases in the speed of steps per second (4-step ascend velocity). This measure stands in for walking ability and is separate from the common measure of stairs climbed per second. Despite this result, Sarepta says that these findings “reinforce the potential impact of these therapies to slow muscle weakness and other symptoms. “
One group of patients could not receive consistent treatment due to the COVID-19 pandemic. Sarepta performed the analysis again without this group. Removing these patients from the dataset suggested a 30% reduction in disease progression over 2 years, as measured by the speed of steps per second (4-step ascend velocity).
The ESSENCE trial treatments had a safety profile similar to that of exon-skipping therapies. Around 10% of patients had moderate side effects, which were manageable and reversible. Common effects of the treatment included vomiting, nasal inflammation, fever, headache, cough, falls, and upper respiratory infections.
Further results from ESSENCE will be shared in the future through medical meetings and journals. For reference, Sarepta’s ESSENCE trial evaluated AMONDYS 45 (casimersen) and VYONDYS 53 (golodirsen) in patients with Duchenne. These treatments use synthetic molecules called ‘morpholinos’ and are mutation-specific. In turn, morpholinos are injected into patients and skip part of the dystrophin gene, producing a shorter yet still potentially active protein. AMONDYS 45 (casimersen) skips exon 45 while VYONDYS 53 (golodirsen) skips exon 53.
Defeat Duchenne Canada is proactively following up with Sarepta for more about Canadian patient access to the company’s Duchenne therapies.
Update written by Defeat Duchenne Canada Research Volunteer Omar Sheikh.