Development of a validated Western blot method for quantification of human dystrophin protein used in phase 2 and 3 clinical trials of eteplirsen for the treatment of Duchenne muscular dystrophy

2017 ◽  
Vol 27 ◽  
pp. S16 ◽  
Author(s):  
F.J. Schnell ◽  
C. Donoghue ◽  
J. Dworzak ◽  
J. Charleston ◽  
D. Frank ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Western Blot ◽  
Phase 2 ◽  
Western Blot Method ◽  
Dystrophin Protein ◽  
Human Dystrophin

scholarly journals Challenges of Interpreting Dystrophin Content by Western Blot

US Neurology ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 40 ◽  
Author(s):  
Frederick J Schnell ◽  
Diane Frank ◽  
Sue Fletcher ◽  
Russell D Johnsen ◽  
Steve D Wilton ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Data Analysis ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Western Blot ◽  
Becker Muscular Dystrophy ◽  
Human Muscle ◽  
Healthy Human ◽  
Dystrophin Protein ◽  
Western Blot Data

The Duchenne muscular dystrophy community has recently seen the first approved therapy for the restoration of dystrophin, based on its ability to increase levels of dystrophin protein, as determined by western blot. The approval, along with the initiation of clinical trials evaluating other dystrophin-restoring therapies, highlights the importance of accurate dystrophin quantitation. Nonoptimized western blot methods can reflect inaccurate results, especially in the quantitation of low dystrophin levels. A few key changes to standards and data analysis parameters can result in a low level of dystrophin (<0.5% of a healthy biopsy) being inaccurately interpreted as >20% of the levels reported in healthy human muscle. A review of the dystrophin western blot data on Duchenne and Becker muscular dystrophy biopsies is conducted, along with a thorough investigation of methodologies to quantify dystrophin.

scholarly journals Increased dystrophin production with golodirsen in patients with Duchenne muscular dystrophy

Neurology ◽  
2020 ◽  
Vol 94 (21) ◽  
pp. e2270-e2282 ◽  
Author(s):  
Diane E. Frank ◽  
Frederick J. Schnell ◽  
Cody Akana ◽  
Saleh H. El-Husayni ◽  
Cody A. Desjardins ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Western Blot ◽  
Exon Skipping ◽  
Study Drug ◽  
Dose Titration ◽  
Open Label ◽  
Double Blind ◽  
Dystrophin Protein ◽  
Muscle Biopsies

ObjectiveTo report safety, pharmacokinetics, exon 53 skipping, and dystrophin expression in golodirsen-treated patients with Duchenne muscular dystrophy (DMD) amenable to exon 53 skipping.MethodsPart 1 was a randomized, double-blind, placebo-controlled, 12-week dose titration of once-weekly golodirsen; part 2 is an ongoing, open-label evaluation. Safety and pharmacokinetics were primary and secondary objectives of part 1. Primary biological outcome measures of part 2 were blinded exon skipping and dystrophin protein production on muscle biopsies (baseline, week 48) evaluated, respectively, using reverse transcription PCR and Western blot and immunohistochemistry.ResultsTwelve patients were randomized to receive golodirsen (n = 8) or placebo (n = 4) in part 1. All from part 1 plus 13 additional patients received 30 mg/kg golodirsen in part 2. Safety findings were consistent with those previously observed in pediatric patients with DMD. Most of the study drug was excreted within 4 hours following administration. A significant increase in exon 53 skipping was associated with ∼16-fold increase over baseline in dystrophin protein expression at week 48, with a mean percent normal dystrophin protein standard of 1.019% (range, 0.09%–4.30%). Sarcolemmal localization of dystrophin was demonstrated by significantly increased dystrophin-positive fibers (week 48, p < 0.001) and a positive correlation (Spearman r = 0.663; p < 0.001) with dystrophin protein change from baseline, measured by Western blot and immunohistochemistry.ConclusionGolodirsen was well-tolerated; muscle biopsies from golodirsen-treated patients showed increased exon 53 skipping, dystrophin production, and correct dystrophin sarcolemmal localization.Clinicaltrials.gov identifierNCT02310906.Classification of evidenceThis study provides Class I evidence that golodirsen is safe and Class IV evidence that it induces exon skipping and novel dystrophin as confirmed by 3 different assays.

scholarly journals Development of Multiexon Skipping Antisense Oligonucleotide Therapy for Duchenne Muscular Dystrophy

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yoshitsugu Aoki ◽  
Toshifumi Yokota ◽  
Matthew J. A. Wood
Keyword(s):  
Clinical Trials ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Genetic Disorder ◽  
Premature Death ◽  
Degenerative Disorder ◽  
Antisense Oligonucleotide Therapy ◽  
Treat All ◽  
Dystrophin Protein ◽  
Preclinical Work

Duchenne muscular dystrophy (DMD) is an incurable, X-linked progressive muscle degenerative disorder that results from the absence of dystrophin protein and leads to premature death in affected individuals due to respiratory and/or cardiac failure typically by age of 30. Very recently the exciting prospect of an effective oligonucleotide therapy has emerged which restores dystrophin protein expression to affected tissues in DMD patients with highly promising data from a series of clinical trials. This therapeutic approach is highly mutation specific and thus is personalised. Therefore DMD has emerged as a model genetic disorder for understanding and overcoming of the challenges of developing personalised genetic medicines. One of the greatest weaknesses of the current oligonucleotide approach is that it is a mutation-specific therapy. To address this limitation, we have recently demonstrated that exons 45–55 skipping therapy has the potential to treat clusters of mutations that cause DMD, which could significantly reduce the number of compounds that would need to be developed in order to successfully treat all DMD patients. Here we discuss and review the latest preclinical work in this area as well as a variety of accompanying issues, including efficacy and potential toxicity of antisense oligonucleotides, prior to human clinical trials.

Development of a validated western blot method for quantification of human dystrophin protein

2016 ◽  
Vol 26 ◽  
pp. S160 ◽  
Author(s):  
F. Schnell ◽  
C. Donoghue ◽  
J. Dworzak ◽  
J. Charleston ◽  
D. Frank ◽  
...  
Keyword(s):  
Western Blot ◽  
Western Blot Method ◽  
Dystrophin Protein ◽  
Human Dystrophin

scholarly journals Genotype characterization and delayed loss of ambulation by glucocorticoids in a large cohort of patients with Duchenne muscular dystrophy

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Shu Zhang ◽  
◽  
Dongdong Qin ◽  
Liwen Wu ◽  
Man Li ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Hazard Ratio ◽  
Large Cohort ◽  
Muscle Disease ◽  
Clinical Progression ◽  
Large Deletions ◽  
The Mean ◽  
Lower Hazard

Abstract Background Duchenne muscular dystrophy (DMD) is the most common genetic muscle disease in human. We aimed to describe the genotype distribution in a large cohort of Chinese DMD patients and their delayed loss of ambulation by glucocorticoid (GC) treatments. This is to facilitate protocol designs and outcome measures for the emerging DMD clinical trials. Results A total of 1163 patients with DMD were recruited and genotyped. Genotype variations were categorized as large deletions, large duplications, and small mutations. Large deletions were further analyzed for those amenable to exon-skipping therapies. Participants aged 5 years or older were grouped into GC-treated and GC-naïve groups. Clinical progression among different genotypes and their responses to GC treatments were measured by age at loss of ambulation (LOA). Among the mutation genotypes, large deletions, large duplications, and small mutations accounted for 68.79%, 7.14%, and 24.07%, respectively. The mean age at diagnosis was 4.59 years; the median ages at LOA for the GC-naïve, prednisone/prednisolone-treated, and deflazacort-treated groups were 10.23, 12.02, and 13.95 years, respectively. The “deletion amenable to skipping exon 44” subgroup and the nonsense-mutation subgroup had older ages at LOA than the “other deletions” subgroup. Subgroups were further analyzed by both genotypes and GC status. All genotypes showed significant beneficial responses to GC treatment. Deletions amenable to skipping exon 44 showed a lower hazard ratio (0.155). The mean age at death was 18.57 years in this DMD group. Conclusion Genotype variation influences clinical progression in certain DMD groups. Beneficial responses to GC treatment were observed among all DMD genotypes. Compared with other genotypes, deletions amenable to skipping exon 44 had a lower hazard ratio, which may indicate a stronger protective effect of GC treatments on this subgroup. These data are valuable for designing future clinical trials, as clinical outcomes may be influenced by the genotypes.

scholarly journals The administration of antisense oligonucleotide golodirsen reduces pathological regeneration in patients with Duchenne muscular dystrophy

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Dominic Scaglioni ◽  
Francesco Catapano ◽  
Matthew Ellis ◽  
Silvia Torelli ◽  
Darren Chambers ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Antisense Oligonucleotide ◽  
De Novo ◽  
Exon Skipping ◽  
Significant Negative Correlation ◽  
Entire Cohort ◽  
Associated Proteins ◽  
Analysis Platform ◽  
Dystrophin Protein

AbstractDuring the last decade, multiple clinical trials for Duchenne muscular dystrophy (DMD) have focused on the induction of dystrophin expression using different strategies. Many of these trials have reported a clear increase in dystrophin protein following treatment. However, the low levels of the induced dystrophin protein have raised questions on its functionality. In our present study, using an unbiased, high-throughput digital image analysis platform, we assessed markers of regeneration and levels of dystrophin associated protein via immunofluorescent analysis of whole muscle sections in 25 DMD boys who received 48-weeks treatment with exon 53 skipping morpholino antisense oligonucleotide (PMO) golodirsen. We demonstrate that the de novo dystrophin induced by exon skipping with PMO golodirsen is capable of conferring a histological benefit in treated patients with an increase in dystrophin associated proteins at the dystrophin positive regions of the sarcolemma in post-treatment biopsies. Although 48 weeks treatment with golodirsen did not result in a significant change in the levels of fetal/developmental myosins for the entire cohort, there was a significant negative correlation between the amount of dystrophin and levels of regeneration observed in different biopsy samples. Our results provide, for the first time, evidence of functionality of induced dystrophin following successful therapeutic intervention in the human.

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