An unmet need remains for safe and efficacious treatments for Duchenne muscular dystrophy (DMD). To date, there are limited agents available that address the underlying cause of the disease.
To ...evaluate the safety, tolerability, and efficacy of viltolarsen, a novel antisense oligonucleotide, in participants with DMD amenable to exon 53 skipping.
This phase 2 study was a 4-week randomized clinical trial for safety followed by a 20-week open-label treatment period of patients aged 4 to 9 years with DMD amenable to exon 53 skipping. To enroll 16 participants, with 8 participants in each of the 2 dose cohorts, 17 participants were screened. Study enrollment occurred between December 16, 2016, and August 17, 2017, at sites in the US and Canada. Data were collected from December 2016 to February 2018, and data were analyzed from April 2018 to May 2019.
Participants received 40 mg/kg (low dose) or 80 mg/kg (high dose) of viltolarsen administered by weekly intravenous infusion.
Primary outcomes of the trial included safety, tolerability, and de novo dystrophin protein production measured by Western blot in participants' biceps muscles. Secondary outcomes included additional assessments of dystrophin mRNA and protein production as well as clinical muscle strength and function.
Of the 16 included boys with DMD, 15 (94%) were white, and the mean (SD) age was 7.4 (1.8) years. After 20 to 24 weeks of treatment, significant drug-induced dystrophin production was seen in both viltolarsen dose cohorts (40 mg/kg per week: mean range 5.7% 3.2-10.3 of normal; 80 mg/kg per week: mean range 5.9% 1.1-14.4 of normal). Viltolarsen was well tolerated; no treatment-emergent adverse events required dose reduction, interruption, or discontinuation of the study drug. No serious adverse events or deaths occurred during the study. Compared with 65 age-matched and treatment-matched natural history controls, all 16 participants treated with viltolarsen showed significant improvements in timed function tests from baseline, including time to stand from supine (viltolarsen: -0.19 s; control: 0.66 s), time to run/walk 10 m (viltolarsen: 0.23 m/s; control: -0.04 m/s), and 6-minute walk test (viltolarsen: 28.9 m; control: -65.3 m) at the week 25 visit.
Systemic treatment of participants with DMD with viltolarsen induced de novo dystrophin production, and clinical improvement of timed function tests was observed.
ClinicalTrials.gov Identifier: NCT02740972.
Summary Background Cardiorespiratory failure is the leading cause of death in Duchenne muscular dystrophy. Based on preclinical and phase 2 evidence, we assessed the efficacy and safety of idebenone ...in young patients with Duchenne muscular dystrophy who were not taking concomitant glucocorticoids. Methods In a multicentre phase 3 trial in Belgium, Germany, the Netherlands, Switzerland, France, Sweden, Austria, Italy, Spain, and the USA, patients (age 10–18 years old) with Duchenne muscular dystrophy were randomly assigned in a one-to-one ratio with a central interactive web response system with a permuted block design with four patients per block to receive idebenone (300 mg three times a day) or matching placebo orally for 52 weeks. Study personnel and patients were masked to treatment assignment. The primary endpoint was change in peak expiratory flow (PEF) as percentage predicted (PEF%p) from baseline to week 52, measured with spirometry. Analysis was by intention to treat (ITT) and a modified ITT (mITT), which was prospectively defined to exclude patients with at least 20% difference in the yearly change in PEF%p, measured with hospital-based and weekly home-based spirometry. This study is registered with ClinicalTrials.gov , number NCT01027884. Findings 31 patients in the idebenone group and 33 in the placebo group comprised the ITT population, and 30 and 27 comprised the mITT population. Idebenone significantly attenuated the fall in PEF%p from baseline to week 52 in the mITT (−3·05%p 95% CI −7·08 to 0·97, p=0·134, vs placebo −9·01%p –13·18 to −4·84, p=0·0001; difference 5·96%p 0·16 to 11·76, p=0·044) and ITT populations (−2·57%p –6·68 to 1·54, p=0·215, vs −8·84%p –12·73 to −4·95, p<0·0001; difference 6·27%p 0·61 to 11·93, p=0·031). Idebenone also had a significant effect on PEF (L/min), weekly home-based PEF, FVC, and FEV1 . The effect of idebenone on respiratory function outcomes was similar between patients with previous corticosteroid use and steroid-naive patients. Treatment with idebenone was safe and well tolerated with adverse event rates were similar in both groups. Nasopharyngitis and headache were the most common adverse events (idebenone, eight 25% and six 19% of 32 patients; placebo, nine 26% and seven 21% of 34 patients). Transient and mild diarrhoea was more common in the idebenone group than in the placebo group (eight 25% vs four 12% patients). Interpretation Idebenone reduced the loss of respiratory function and represents a new treatment option for patients with Duchenne muscular dystrophy. Funding Santhera Pharmaceuticals.
ABSTRACT
Introduction: Duchenne muscular dystrophy (DMD) subjects ≥5 years with nonsense mutations were followed for 48 weeks in a multicenter, randomized, double‐blind, placebo‐controlled trial of ...ataluren. Placebo arm data (N = 57) provided insight into the natural history of the 6‐minute walk test (6MWT) and other endpoints. Methods: Evaluations performed every 6 weeks included the 6‐minute walk distance (6MWD), timed function tests (TFTs), and quantitative strength using hand‐held myometry. Results: Baseline age (≥7 years), 6MWD, and selected TFT performance are strong predictors of decline in ambulation (Δ6MWD) and time to 10% worsening in 6MWD. A baseline 6MWD of <350 meters was associated with greater functional decline, and loss of ambulation was only seen in those with baseline 6MWD <325 meters. Only 1 of 42 (2.3%) subjects able to stand from supine lost ambulation. Conclusion: Findings confirm the clinical meaningfulness of the 6MWD as the most accepted primary clinical endpoint in ambulatory DMD trials. Muscle Nerve 48: 343–356, 2013
Duchenne muscular dystrophy (DMD) is a childhood onset muscular dystrophy leading to shortened life expectancy. There are gaps in published DMD care guidelines regarding recently approved DMD ...medications and alternative steroid dosing regimens.
A list of statements about use of currently available therapies for DMD in the United States was developed based on a systematic literature review and expert panel feedback. Panelists' responses were collected using a modified Delphi approach.
Among corticosteroid regimens, either deflazacort or prednisone weekend dosing was preferred when payer requirements do not dictate choice. Most patients with exon 51 skip-amenable mutations should be offered eteplirsen, before or with a corticosteroid.
The options available for medical management of the motor symptoms of DMD are expanding rapidly. The choice of medical therapies should balance expected benefit with side effects.
ABSTRACT
Introduction: An international clinical trial enrolled 174 ambulatory males ≥5 years old with nonsense mutation Duchenne muscular dystrophy (nmDMD). Pretreatment data provide insight into ...reliability, concurrent validity, and minimal clinically important differences (MCIDs) of the 6‐minute walk test (6MWT) and other endpoints. Methods: Screening and baseline evaluations included the 6‐minute walk distance (6MWD), timed function tests (TFTs), quantitative strength by myometry, the PedsQL, heart rate–determined energy expenditure index, and other exploratory endpoints. Results: The 6MWT proved feasible and reliable in a multicenter context. Concurrent validity with other endpoints was excellent. The MCID for 6MWD was 28.5 and 31.7 meters based on 2 statistical distribution methods. Conclusions: The ratio of MCID to baseline mean is lower for 6MWD than for other endpoints. The 6MWD is an optimal primary endpoint for Duchenne muscular dystrophy (DMD) clinical trials that are focused therapeutically on preservation of ambulation and slowing of disease progression. Muscle Nerve 48: 357–368, 2013
Objective
Delandistrogene moxeparvovec is approved in the USA for the treatment of ambulatory patients (4–5 years) with Duchenne muscular dystrophy. ENDEAVOR (SRP‐9001‐103; NCT04626674) is a ...single‐arm, open‐label study to evaluate delandistrogene moxeparvovec micro‐dystrophin expression, safety, and functional outcomes following administration of commercial process delandistrogene moxeparvovec.
Methods
In cohort 1 of ENDEAVOR (N = 20), eligible ambulatory males, aged ≥4 to <8 years, received a single intravenous infusion of delandistrogene moxeparvovec (1.33 × 1014 vg/kg). The primary endpoint was change from baseline (CFBL) to week 12 in delandistrogene moxeparvovec micro‐dystrophin by western blot. Additional endpoints evaluated included: safety; vector genome copies; CFBL to week 12 in muscle fiber‐localized micro‐dystrophin by immunofluorescence; and functional assessments, including North Star Ambulatory Assessment, with comparison with a propensity score‐weighted external natural history control.
Results
The 1‐year safety profile of commercial process delandistrogene moxeparvovec in ENDEAVOR was consistent with safety data reported in other delandistrogene moxeparvovec trials (NCT03375164 and NCT03769116). Delandistrogene moxeparvovec micro‐dystrophin expression was robust, with sarcolemmal localization at week 12; mean (SD) CFBL in western blot, 54.2% (42.6); p < 0.0001. At 1 year, patients demonstrated stabilized or improved North Star Ambulatory Assessment total scores; mean (SD) CFBL, +4.0 (3.5). Treatment versus a propensity score‐weighted external natural history control demonstrated a statistically significant difference in least squares mean (standard error) CFBL in North Star Ambulatory Assessment, +3.2 (0.6) points; p < 0.0001.
Interpretation
Results confirm efficient transduction of muscle by delandistrogene moxeparvovec. One‐year post‐treatment, delandistrogene moxeparvovec was well tolerated, and demonstrated stabilized or improved motor function, suggesting a clinical benefit for patients with Duchenne muscular dystrophy. ANN NEUROL 2023;94:955–968
Delandistrogene moxeparvovec is a gene transfer therapy approved in the United States, United Arab Emirates, and Qatar for the treatment of ambulatory patients aged four through five years with a ...confirmed Duchenne muscular dystrophy (DMD)-causing mutation in the DMD gene. This therapy was developed to address the underlying cause of DMD through targeted skeletal, respiratory, and cardiac muscle expression of delandistrogene moxeparvovec micro-dystrophin, an engineered, functional dystrophin protein.
Drawing on clinical trial experience from Study 101 (NCT03375164), Study 102 (NCT03769116), and ENDEAVOR (Study 103; NCT04626674), we outline practical considerations for delandistrogene moxeparvovec treatment.
Before infusion, the following are recommended: (1) screen for anti-adeno-associated virus rhesus isolate serotype 74 total binding antibody titers <1:400; (2) assess liver function, platelet count, and troponin-I; (3) ensure patients are up to date with vaccinations and avoid vaccine coadministration with infusion; (4) administer additional corticosteroids starting one day preinfusion (for patients already on corticosteroids); and (5) postpone dosing patients with any infection or acute liver disease until event resolution. Postinfusion, the following are recommended: (1) monitor liver function weekly (three months postinfusion) and, if indicated, continue until results are unremarkable; (2) monitor troponin-I levels weekly (first month postinfusion, continuing if indicated); (3) obtain platelet counts weekly (two weeks postinfusion), continuing if indicated; and (4) maintain the corticosteroid regimen for at least 60 days postinfusion, unless earlier tapering is indicated.
Although the clinical safety profile of delandistrogene moxeparvovec has been consistent, monitorable, and manageable, these practical considerations may mitigate potential risks in a real-world clinical practice setting.
ABSTRACT
Introduction: Glucocorticosteroids (GC) are effective in slowing weakness in boys with Duchenne muscular dystrophy (DMD). Methods: This is a multisite, 1‐year, open‐label trial of ...twice‐weekly prednisolone (5 mg/kg/dose) in infants/young boys (0.4–2.4 years) with DMD. We compared changes in Bayley III Scales of Infant Development (Bayley‐III) with untreated boys followed for 1 year (historical control cohort HCC). Twenty‐three of 25 participants completed the study. Results: Treated boys gained an average of 0.5 points on the Bayley‐III gross motor scaled score (GMSS) compared with the HCC who, on average, declined 1.3 points (P = 0.03). All boys maintained linear growth, and none developed Cushingoid features. Excessive weight gain occurred in 13 of 23 (56%) boys. Discussion: This study provides evidence that twice‐weekly GC is well tolerated in infants and young boys with DMD and improves GMSS. Excessive weight gain is a potential risk. Longer follow‐up is required to determine whether early GC initiation is feasible in most infants/boys with DMD. Muscle Nerve 59:650–657, 2019
See editorial on pages 638–639 in this issue.
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