DMD gene therapy Elevidys wins conditional approval in Japan
OK covers children, ages 3-7, without exon 8/9 deletions and antibody-negative
Note: This story was updated May 19, 2025, to clarify the requirements needed for Elevidys to transition to full approval.
The Japanese Ministry of Health, Labour, and Welfare (MHLW) has conditionally approved the gene therapy Elevidys (delandistrogene moxeparvovec-rokl) to treat some cases of Duchenne muscular dystrophy (DMD).
The approval covers its use in children, ages 3-7, who don’t have deletions in exon 8 and/or exon 9 in the DMD gene and are negative for antibodies against the viral vector AAVrh74. Conditional and time-limited, the approval allows Elevidys to be sold in Japan for up to seven years. To transition to a full approval, additional data will need to be generated to further demonstrate the safety and efficacy Elevidys.
“For nearly a decade, Sarepta has been a leader in advancing the treatment of [DMD] through innovative treatment options. With the approval of Elevidys in Japan, children who are living with this rare, fatal disease, one marked by progressive muscle deterioration and weakness, now have an additional treatment option,” Louise Rodino-Klapac, Sarepta’s head of research and development and chief scientific officer, said in a company press release.
Elevidys will be marketed in Japan by Chugai Pharmaceuticals, a member of the Roche group. Roche is responsible for commercializing Elevidys outside the U.S. under a 2019 agreement with Sarepta.
“Sarepta is committed to supporting our partners so we can bring this treatment to additional people with Duchenne around the world who urgently need a therapy that potentially addresses the root cause of disease,” Rodino-Klapac said.
DMD is caused by mutations in the DMD gene, which provides instructions to make dystrophin, a protein that helps maintain muscle health. Elevidys delivers a modified version of DMD that encodes a shortened version of dystrophin, called micro-dystrophin, to muscle cells.
Approvals of Elevidys
In the U.S, the gene therapy isn’t recommended for people with deletions in parts of the DMD gene called exon 8 and exon 9 because these patients can have dangerous immune reactions. Elevidys delivers its genetic payload using a modified virus called AAVrh74, so it’s also not recommended for people with significant antibodies against this viral vector because that might trigger an immune response that causes health problems or stops the therapy from working as designed. In Japan, patients must be negative for anti-AAVrh74 antibodies.
In the U.S., Elevidys is fully approved for DMD patients, ages 4 and older, who can walk, and conditionally approved for the same ages who cannot walk. The approval in Japan, which covers patients as young as 3, is the first to include children younger than 4.
Approvals of Elevidys in Japan and the U.S. were based largely on data from EMBARK (NCT05096221), a Phase 3 clinical trial that tested it in more than 120 boys with DMD. In the study’s first part, participants were given either Elevidys or a placebo and followed for a year, then those who’d originally been given the placebo were given Elevidys.
After a year, the boys given Elevidys performed better than those given the placebo on a range of motor measurements, including the time it took to walk a short distance or stand from lying down. Recent longer-term analyses have shown that motor function continued to improve in those given Elevidys.
A recent analysis compared how Elevidys affected muscle tissue in boys given the gene therapy or a placebo in the trial’s first year and the findings were published in JAMA Neurology in the study, “Quantitative Muscle Magnetic Resonance Outcomes in Patients With Duchenne Muscular Dystrophy: An Exploratory Analysis From the EMBARK Randomized Clinical Trial.”
When muscle is lost in DMD, the lost muscle tissue is generally replaced with fat, so the fat fraction in muscles tends to increase as the disease progresses. This analysis, which included 19 boys given Elevidys and 20 given a placebo who underwent muscle imaging tests, suggested that patients given the gene therapy had less fat accumulation in their muscles, suggesting that Elevidys helps prevent muscle tissue from being lost. The results were largely consistent across different muscles and in children of varying ages.
“Overall, [imaging] outcomes in the EMBARK trial indicated worsening muscle health in patients treated with placebo [versus] stabilization or slowing of disease progression in patients treated with [Elevidys] over the 52-week follow-up period,” the researchers wrote.
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