Trials For Duchenne Muscular Dystrophy Research Articles

DUCHENNE MUSCULAR DYSTROPHY – IMAGING AND BIOMARKERS: P.34MR biomarkers in imaging DMD clinical trial network

MR biomarkers have shown considerable promise as outcome measures in clinical trials for Duchenne muscular dystrophy (DMD). Imaging DMD has developed an extensive clinical trial network with an infrastructure that enables high quality MR data collection across centers. The infrastructure incorporates standardized acquisition procedures, efficient data management, automated processing of images and spectra as a pipeline, phantoms, and quality assurance procedures. MR procedures have been successfully implemented for measuring fat fraction (FF) by both magnetic resonance spectroscopy (1H-MRS) and Dixon imaging, as well as the MRI transverse relaxation time constant (T2), enabling cross validation among measures. In addition, we measure 1H2O T2 using single voxel 1H-MRS as a marker of membrane stability and inflammation. In this study, we describe the infrastructure and MR methods used in these studies, and compare the sensitivity of these measurements to disease progression in a range of lower extremity muscles and ages using data acquired at three centers using 3T MR systems in 138 individuals with DMD (8.8±3.3 years) and 51 unaffected controls (8.8±2.4 years). Our results show a range of involvement and disease progression among muscles, with each MR measure able to robustly discriminate unaffected controls and DMD (p<0.05). Furthermore, the MR measures of muscle FF and MRI T2 were all able to detect longitudinal changes within one year (p<0.05) in the soleus and vastus lateralis. Overall, the Imaging DMD Clinical Trial Network has successfully implemented standardized MR procedures over multiple sites, and presently includes 21 certified MR sites across North America and Europe.

Slope Analysis of 6-Minute Walk Dstance as an Alternative Method to Determine Treatment Effect in Trials in Duchenne Muscular dystrophy (P2.331)

Slope Analysis of 6-Minute Walk Dstance as an Alternative Method to Determine Treatment Effect in Trials in Duchenne Muscular dystrophy (P2.331)

D23 - Slope analysis of 6-minute walk distance as an alternative method to determine treatment effect in trials in Duchenne muscular dystrophy

D23 - Slope analysis of 6-minute walk distance as an alternative method to determine treatment effect in trials in Duchenne muscular dystrophy

A novel high-throughput immunofluorescence analysis method for quantifying dystrophin intensity in entire transverse sections of Duchenne muscular dystrophy muscle biopsy samples.

Clinical trials using strategies aimed at inducing dystrophin expression in Duchenne muscular dystrophy (DMD) are underway or at advanced planning stage, including splice switching antisense oligonucleotides (AON), drugs to induce read-through of nonsense mutations and viral mediated gene therapy. In all these strategies, different dystrophin proteins, often internally deleted, are produced, similar to those found in patients with the milder DMD allelic variant, Becker muscular dystrophy (BMD). The primary biological endpoint of these trials is to induce functional dystrophin expression. A reliable and reproducible method for quantification of dystrophin protein expression at the sarcolemma is crucial to monitor the biochemical outcome of such treatments. We developed a new high throughput semi quantitative fluorescent immunofluorescence method for quantifying dystrophin expression in transverse sections of skeletal muscle. This technique is completely operator independent as it based on an automated scanning system and an image processing script developed with Definiens software. We applied this new acquisition-analysis method to quantify dystrophin and sarcolemma-related proteins using paediatric control muscles from cases without a neuromuscular disorder as well as DMD and BMD samples. The image analysis script was instructed to recognize myofibres immunostained for spectrin or laminin while dystrophin was quantified in each identified myofibre (from 2,000 to over 20,000 fibres, depending on the size of the biopsy). We were able to simultaneously extrapolate relevant parameters such as mean sarcolemmal dystrophin, mean spectrin and laminin intensity, fibre area and diameter. In this way we assessed dystrophin production in each muscle fibre in samples of DMD, BMD and controls. This new method allows the unbiased quantification of dystrophin in every myofibre within a transverse muscle section and will be of help for translational research projects as a biological outcome in clinical trials in DMD and BMD.

An Overview of Recent Advances and Clinical Applications of Exon Skipping and Splice Modulation for Muscular Dystrophy and Various Genetic Diseases.

Exon skipping is a therapeutic approach that is feasible for various genetic diseases and has been studied and developed for over two decades. This approach uses antisense oligonucleotides (AON) to modify the splicing of pre-mRNA to correct the mutation responsible for a disease, or to suppress a particular gene expression, as in allergic diseases. Antisense-mediated exon skipping is most extensively studied in Duchenne muscular dystrophy (DMD) and has developed from in vitro proof-of-concept studies to clinical trials targeting various single exons such as exon 45 (casimersen), exon 53 (NS-065/NCNP-01, golodirsen), and exon 51 (eteplirsen). Eteplirsen (brand name Exondys 51), is the first approved antisense therapy for DMD in the USA, and provides a treatment option for ~14% of all DMD patients, who are amenable to exon 51 skipping. Eteplirsen is granted accelerated approval and marketing authorization by the US Food and Drug Administration (FDA), on the condition that additional postapproval trials show clinical benefit. Permanent exon skipping achieved at the DNA level using clustered regularly interspaced short palindromic repeats (CRISPR) technology holds promise in current preclinical trials for DMD. In hopes of achieving clinical success parallel to DMD, exon skipping and splice modulation are also being studied in other muscular dystrophies, such as Fukuyama congenital muscular dystrophy (FCMD), dysferlinopathy including limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM), and distal anterior compartment myopathy (DMAT), myotonic dystrophy, and merosin-deficient congenital muscular dystrophy type 1A (MDC1A). This chapter also summarizes the development of antisense-mediated exon skipping therapy in diseases such as Usher syndrome, dystrophic epidermolysis bullosa, fibrodysplasia ossificans progressiva (FOP), and allergic diseases.

The Use of Antisense Oligonucleotides for the Treatment of Duchenne Muscular Dystrophy.

Antisense oligonucleotides (AONs) hold great promise for therapeutic splice-switching correction in many genetic diseases and in particular for Duchenne muscular dystrophy (DMD), where AONs can be used to reframe the dystrophin transcript and give rise to a partially deleted but yet functional dystrophin protein. Many different chemistries of AONs can be used for splice switching modulation, and some of them have been evaluated in clinical trials for DMD. However, despite advances in AON chemistry and design, systemic use of AONs is limited due to poor tissue uptake, and sufficient therapeutic efficacy is difficult to achieve. Therefore, there is still a critical need to develop efficient AONs able to restore the expression of dystrophin in all relevant tissues and international efforts are currently on going to develop new compounds or alternative chemistries with higher therapeutic potential. Here, we describe the methods to evaluate the potency of antisense oligonucleotides, and in particular of tricyclo-DNA (tcDNA)-AONs, a novel class of AONs which displays unique pharmacological properties and unprecedented uptake in many tissues after systemic administration. We focus on the most widely used mouse model for DMD, the mdx mouse and detail methods to analyze the skipping of the mouse exon 23 both in vitro in H2K mdx cells and in vivo in the mdx mouse model.

P.467 - A clinical update on the eNHANCE project: Eye tracking control for reaching and grasping in an adolescent Duchenne muscular dystrophy (DMD) population

Disease progression in Duchenne muscular dystrophy (DMD), an X-linked genetic condition, leads to loss of ambulation and deterioration in the function of the upper limb (UL). Compensation for UL function is more difficult than loss of ambulation, because of the complexity of UL movements. The poor uptake of current assistive devices is attributed to a gap between users' needs and design of the technology. The eNHANCE project aims to design an eye tracking controlled prototypic robotic arm support to improve the functional performances of those with DMD. As the project aims to employ an End-User driven approach to reduce this gap, a focus group of 15 end users (6 DMD subjects, 9 carers) and 3 therapists was held to determine the disease-specific needs of this population. The results found that the most important features specific to this group were: subconscious control which could be switched off, bilateral, mobile, waterproof, and long battery life. These results were then fedback into the design of the device. The eNHANCE device was then trialled in a healthy volunteer as a precursor to clinical trials in DMD. This demonstrated “proof of concept” with the eyetracker. The robotic arm support successfully moved to its desired target in 10/30 attempts (33%) with an average accuracy of 4.7–5.0 cm. Technical issues with respect to positioning of device deferred clinical trials with arm support alone. Clinical trials in DMD using eyetracking control of the robotic arm support with further assistance of a bio-glove for grasping support are planned for autumn 2017. MCID (Minimum clinically important difference) using PUL (Performance of Upper Limb) will also be assessed at this time.

Ataluren in patients with nonsense mutation Duchenne muscular dystrophy (ACT DMD): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

Duchenne muscular dystrophy (DMD) is a severe, progressive, and rare neuromuscular, X-linked recessive disease. Dystrophin deficiency is the underlying cause of disease; therefore, mutation-specific therapies aimed at restoring dystrophin protein production are being explored. We aimed to assess the efficacy and safety of ataluren in ambulatory boys with nonsense mutation DMD. We did this multicentre, randomised, double-blind, placebo-controlled, phase 3 trial at 54 sites in 18 countries located in North America, Europe, the Asia-Pacific region, and Latin America. Boys aged 7-16 years with nonsense mutation DMD and a baseline 6-minute walk distance (6MWD) of 150 m or more and 80% or less of the predicted normal value for age and height were randomly assigned (1:1), via permuted block randomisation (block size of four) using an interactive voice-response or web-response system, to receive ataluren orally three times daily (40 mg/kg per day) or matching placebo. Randomisation was stratified by age (<9 years vs ≥9 years), duration of previous corticosteroid use (6 months to <12 months vs ≥12 months), and baseline 6MWD (<350 m vs ≥350 m). Patients, parents and caregivers, investigational site personnel, PTC Therapeutics employees, and all other study personnel were masked to group allocation until after database lock. The primary endpoint was change in 6MWD from baseline to week 48. We additionally did a prespecified subgroup analysis of the primary endpoint, based on baseline 6MWD, which is reflective of anticipated rates of disease progression over 1 year. The primary analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01826487. Between March 26, 2013, and Aug 26, 2014, we randomly assigned 230 patients to receive ataluren (n=115) or placebo (n=115); 228 patients comprised the intention-to-treat population. The least-squares mean change in 6MWD from baseline to week 48 was -47·7 m (SE 9·3) for ataluren-treated patients and -60·7 m (9·3) for placebo-treated patients (difference 13·0 m [SE 10·4], 95% CI -7·4 to 33·4; p=0·213). The least-squares mean change for ataluren versus placebo in the prespecified subgroups was -7·7 m (SE 24·1, 95% CI -54·9 to 39·5; p=0·749) in the group with a 6MWD of less than 300 m, 42·9 m (15·9, 11·8-74·0; p=0·007) in the group with a 6MWD of 300 m or more to less than 400 m, and -9·5 m (17·2, -43·2 to 24·2; p=0·580) in the group with a 6MWD of 400 m or more. Ataluren was generally well tolerated and most treatment-emergent adverse events were mild to moderate in severity. Eight (3%) patients (n=4 per group) reported serious adverse events; all except one event in the placebo group (abnormal hepatic function deemed possibly related to treatment) were deemed unrelated to treatment. Change in 6MWD did not differ significantly between patients in the ataluren group and those in the placebo group, neither in the intention-to-treat population nor in the prespecified subgroups with a baseline 6MWD of less than 300 m or 400 m or more. However, we recorded a significant effect of ataluren in the prespecified subgroup of patients with a baseline 6MWD of 300 m or more to less than 400 m. Baseline 6MWD values within this range were associated with a more predictable rate of decline over 1 year; this finding has implications for the design of future DMD trials with the 6-minute walk test as the endpoint. PTC Therapeutics.

Slope analysis of 6-minute walk distance as an alternative method to determine treatment effect in trials in Duchenne muscular dystrophy

Slope analysis of 6-minute walk distance as an alternative method to determine treatment effect in trials in Duchenne muscular dystrophy

Electrical impedance myography for assessment of Duchenne muscular dystrophy.

Sensitive, objective, and easily applied methods for evaluating disease progression and response to therapy are needed for clinical trials in Duchenne muscular dystrophy (DMD). In this study, we evaluated whether electrical impedance myography (EIM) could serve this purpose. In this nonblinded study, 36 boys with DMD and 29 age-similar healthy boys underwent multifrequency EIM measurements for up to 2 years on 6 muscles unilaterally along with functional assessments. A linear mixed-effects model with random intercept and slope terms was used for the analysis of multifrequency EIM values and functional measures. Seven DMD boys were initiated on corticosteroids; these data were analyzed using a piecewise linear mixed-effects model. In boys > 7.0 years old, a significant difference in the slope of EIM phase ratio trajectories in the upper extremity was observed by 6 months of -0.074/month, p = 0.023, 95% confidence interval (CI) = -0.013, -0.14; at 2 years, this difference was -0.048/month, p < 0.0001, 95% CI = -0.028, -0.068. In boys ≤ 7.0 years old, differences appeared at 6 months in gastrocnemius (EIM phase slope = -0.83 °/kHz/mo, p = 0.007, 95% CI = -0.26, -1.40). EIM outcomes showed significant differences earlier than functional tests. Initiation of corticosteroids significantly improved the slope of EIM phase ratio (0.057/mo, p = 0.00019, 95% CI = 0.028, 0.086) and EIM phase slope (0.14 °/kHz/mo, p = 0.013, 95% CI = 0.028, 0.25), consistent with corticosteroids' known clinical benefit. EIM detects deterioration in muscles of both younger and older boys by 6 months; it also identifies the therapeutic effect of corticosteroid initiation. Because EIM is rapid to apply, painless, and requires minimal operator training, the technique deserves to be further evaluated as a biomarker in DMD clinical therapeutic trials. Ann Neurol 2017;81:622-632.

Clinical and mutational characteristics of Duchenne muscular dystrophy patients based on a comprehensive database in South China

The development of clinical trials for Duchenne muscular dystrophy (DMD) in China faces many challenges due to limited information about epidemiological data, natural history and clinical management. To provide these detailed data, we developed a comprehensive database based on registered DMD patients from South China and analysed their clinical and mutational characteristics. The database included DMD registrants confirmed by clinical presentation, family history, genetic detection, prognostic outcome, and/or muscle biopsy. Clinical data were collected by a registry form. Mutations of dystrophin were detected by multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing. Currently, 132 DMD patients from 128 families in South China have been registered, and 91.7% of them were below 10 years old. In mutational detection, large deletions were the most frequent type (57.8%), followed by small deletion/insertion mutations (14.1%), nonsense mutations (13.3%), large duplications (10.9%), and splice site mutations (3.1%). Clinical analysis revealed that most patients reported initial symptoms between 1 and 3 years of age, but the diagnostic age was more frequently between 6 and 8 years. 81.4% of patients were ambulatory. Baseline cardiac assessments at diagnosis were conducted in 39.4% and 29.5% of patients by echocardiograms and electrocardiograms, respectively. Only 22.7% of registrants performed baseline respiratory assessments. A small numbers of patients (20.5%) were treated with glucocorticoids. 13.3% of patients were eligible for stop codon read-through therapy, and 48.4% of patients would potentially benefit from exon skipping. The top five exon skips applicable to the largest group of registrants were skipping of exons 51 (14.8% of total mutations), 53 (12.5%), 45 (7.0%), 55 (4.7%), and 44 (3.9%). In conclusion, our database provided information on the natural history, diagnosis and management status of DMD in South China, as well as potential molecular therapies suitable for these patients. This comprehensive database will promote future experimental therapies in China.

Non-uniform muscle fat replacement along the proximodistal axis in Duchenne muscular dystrophy

The progressive replacement of muscle tissue by fat in Duchenne muscular dystrophy (DMD) has been studied using quantitative MRI between, but not within, individual muscles. We studied fat replacement along the proximodistal muscle axis using the Dixon technique on a 3T MR scanner in 22 DMD patients and 12 healthy controls. Mean fat fractions per muscle per slice for seven lower and upper leg muscles were compared between and within groups assuming a parabolic distribution. Average fat fraction for a small central slice stack and a large coverage slice stack were compared to the value when the stack was shifted one slice (15 mm) up or down. Higher fat fractions were observed in distal and proximal muscle segments compared to the muscle belly in all muscles of the DMD subjects (p < 0.001). A shift of 15 mm resulted in a difference in mean fat fraction which was on average 1–2% ranging up to 12% (p < 0.01). The muscle end regions are exposed to higher mechanical strain, which points towards mechanical disruption of the sarcolemma as one of the key factors in the pathophysiology. Overall, this non-uniformity in fat replacement needs to be taken into account to prevent sample bias when applying quantitative MRI as biomarker in clinical trials for DMD.

Isolation and Characterization of Vessel-Associated Stem/Progenitor Cells from Skeletal Muscle.

More than 10 years ago, we isolated from mouse embryonic dorsal aorta a population of vessel-associated stem/progenitor cells, originally named mesoangioblasts (MABs ) , capable to differentiate in all mesodermal-derived tissues, including skeletal muscle. Similar though not identical cells have been later isolated and characterized from small vessels of adult mouse and human skeletal muscles. When delivered through the arterial circulation, MABs cross the blood vessel wall and participate in skeletal muscle regeneration , leading to an amelioration of muscular dystrophies in different preclinical animal models. As such, human MABs have been used under clinical-grade conditions for a Phase I/II clinical trial for Duchenne muscular dystrophy , just concluded. Although some pericyte markers can be used to identify mouse and human MABs , no single unequivocal marker can be used to isolate MABs . As a result, MABs are mainly defined by their isolation method and functional properties. This chapter provides detailed methods for isolation, culture, and characterization of MABs in light of the recent identification of a new marker, PW1 /Peg3, to screen and identify competent MABs before their use in cell therapy.

Invention and Early History of Morpholinos: From Pipe Dream to Practical Products.

Beginning with my concept in 1969 to treat disease at the nucleic acid level using antisense nucleic acids, antisense has evolved to the current Morpholino oligos. Morpholinos have been the dominant gene knockdown system in developmental biology. Lack of delivery technologies has limited their use in adult animals (including humans), though alteration in muscles in Duchenne muscular dystrophy (DMD) allows delivery into adult muscle. Morpholinos are currently in Phase 3 clinical trials for DMD and a Morpholino oligo for skipping dystrophin exon 51 has been approved by the US FDA. With improved delivery techniques, such as those in development at Gene Tools, therapeutic Morpholinos for many difficult-to-treat diseases will be possible. Initial applications are expected to be custom cocktails of delivery-enabled Morpholinos for treating cancers.

Nutraceuticals and Their Potential to Treat Duchenne Muscular Dystrophy: Separating the Credible from the Conjecture.

In recent years, complementary and alternative medicine has become increasingly popular. This trend has not escaped the Duchenne Muscular Dystrophy community with one study showing that 80% of caregivers have provided their Duchenne patients with complementary and alternative medicine in conjunction with their traditional treatments. These statistics are concerning given that many supplements are taken based on purely “anecdotal” evidence. Many nutraceuticals are thought to have anti-inflammatory or anti-oxidant effects. Given that dystrophic pathology is exacerbated by inflammation and oxidative stress these nutraceuticals could have some therapeutic benefit for Duchenne Muscular Dystrophy (DMD). This review gathers and evaluates the peer-reviewed scientific studies that have used nutraceuticals in clinical or pre-clinical trials for DMD and thus separates the credible from the conjecture.

Clinical potential of ataluren in the treatment of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is an autosomal dominant, X-linked neuromuscular disorder caused by mutations in dystrophin, one of the largest genes known to date. Dystrophin gene mutations are generally transmitted from the mother to male offspring and can occur throughout the coding length of the gene. The majority of the methodologies aimed at treating the disorder have focused on restoring a shorter, although partially functional, dystrophin protein. The approach has the potential of converting a severe DMD phenotype into a milder form of the disease known as Becker muscular dystrophy. Others have focused on ameliorating the disease by targeting secondary pathologies such as inflammation or loss of regeneration. Of great potential is the development of strategies that are capable of restoring full-length dystrophin expression due to their ability to produce a normal, fully functional protein. Among these strategies, the use of read-through compounds (RTCs) that could be administered orally represents an ideal option. Gentamicin has been previously tested in clinical trials for DMD with limited or no success, and its use in the clinic has been dismissed due to issues of toxicity and lack of clear benefits to patients. More recently, new RTCs have been identified and tested in animal models for DMD. This review will focus on one of those RTCs known as ataluren that has now completed Phase III clinical studies for DMD and at providing an overview of the different stages that have led to its clinical development for the disease. The impact that this new drug may have on DMD and its future perspectives will also be described, with an emphasis on the importance of further assessing the clinical benefits of this molecule in patients as it becomes available on the market in different countries.

Engaging Participants in Rare Disease Research: A Qualitative Study of Duchenne Muscular Dystrophy

PurposeClinical trials in Duchenne muscular dystrophy (DMD) are increasing due to technical advances in genetics, muscle biology and muscle imaging, and translational science. Yet the ability to achieve and measure progress in clinical trials in DMD is severely constrained by recruitment difficulties and low levels of patient and family participation. Clinical trials that do not have full inclusion of patients may affect how well new therapies perform in clinical practice. MethodsThis study qualitatively investigated family-centered and clinician-based knowledge, attitudes, and perceptions of engagement in clinical research in DMD. Thirteen focus-group sessions (8 parent based and 5 clinician based) were held at 5 demographically and geographically diverse sites (Houston, Texas; Minneapolis, Minnesota; Pittsburgh, Pennsylvania; Sacramento, California; and Washington, DC). Thematic analysis was used for identifying patterns of meaning across the dataset. FindingsTotals of 28 parents and 33 clinicians participated in innovative and thoughtful discussions regarding clinical research in DMD and approaches to eliciting family engagement. Five overarching themes emerged from our qualitative data. The theme of Information discussed the lack of accessible and coherent information, as well as the overabundance of fragmented information. The theme of Conversation demonstrated the importance of having open and in-depth dialogue about research with families in eliciting trust and obligation toward the research process. The Barriers and Incentives themes presented the parents’ and clinicians’ views of the life-altering sacrifices that families make to participate in research and ways to reduce these burdens. Under the Solutions theme, parents and clinicians also suggested innovative ways to incentivize families and clinics and thoughtful solutions to increase family engagement in research. ImplicationsEffective recruitment for clinical studies in rare diseases requires a truly committed and engaged study team, as well as the necessary resources to overcome the multitude of barriers that families face. A clearly delineated recruitment plan, developed together with families, should be the standard operating procedure during clinical trial development. Protocols utilizing direct family-centered strategies for providing information and for recruiting research participants in studies in rare diseases are essential.

Clinical utility of serum biomarkers in Duchenne muscular dystrophy.

Assessments of disease progression and response to therapies in Duchenne muscular dystrophy (DMD) patients remain challenging. Current DMD patient assessments include complex physical tests and invasive procedures such as muscle biopsies, which are not suitable for young children. Defining alternative, less invasive and objective outcome measures to assess disease progression and response to therapy will aid drug development and clinical trials in DMD. In this review we highlight advances in development of non-invasive blood circulating biomarkers as a means to assess disease progression and response to therapies in DMD.Electronic supplementary materialThe online version of this article (doi:10.1186/s12014-016-9109-x) contains supplementary material, which is available to authorized users.

T2 relaxation times are increased in Skeletal muscle of DMD but not BMD patients.

Exon-skipping drugs in Duchenne muscular dystrophy (DMD) aim to restore truncated dystrophin expression, which is present in the milder Becker muscular dystrophy (BMD). MRI skeletal muscle T2 relaxation times as a representation of edema/inflammation could be quantitative outcome parameters for such trials. We studied T2 relaxation times, adjusted for muscle fat fraction using Dixon MRI, in lower leg muscles of DMD and BMD patients and healthy controls. T2 relaxation times correlated significantly with fat fractions in patients only (P < 0.001). After adjusting for muscle fat, T2 relaxation times were significantly increased in 6 muscles of DMD patients (P < 0.01), except for the extensor digitorum longus. In BMD, T2 relaxation times were unchanged. T2 relaxation times could be a useful outcome parameter in exon-skipping trials in DMD but are influenced by fat despite fat suppression. This should be accounted for when using quantitative T2 mapping to investigate edema/inflammation.

“Watching time tick by…”: Decision making for Duchenne muscular dystrophy trials

ObjectiveThis interview study explored clinicians' perspectives and parents' decision making about children's participation in Duchenne muscular dystrophy (DMD) clinical trials. MethodsData from semi-structured interviews conducted with clinicians and parents in U.S. or Canada were assessed using thematic analysis. ResultsEleven clinicians involved in ten trials and fifteen parents involved in six trials were interviewed. Parents described benefit–risk assessments using information from advocacy, peers, professionals, and sponsors. Strong influence was attributed to the progressive nature of DMD. Most expected direct benefit. Few considered the possibility of trial failure. Most made decisions to participate before the informed consent (IC) process, but none-the-less perceived informed choice with little to lose for potential gain.Clinicians described more influence on parental decisions than attributed by parents. Clinicians felt responsible to facilitate IC while maintaining hope. Both clinicians and parents reported criticisms about the IC process and regulatory barriers. ConclusionsThe majority of parents described undertaking benefit–risk assessments that led to informed choices that offered psychological and potential disease benefits. Parents' high expectations influenced their decisions while also reflecting optimism. Clinicians felt challenged in balancing parents' expectations and likely outcomes. Prognosis-related pressures coupled with decision making prior to IC suggest an obligation to ensure educational materials are understandable and accurate, and to consider an expanded notion of IC timeframes. Anticipatory guidance about potential trial failure might facilitate parents' deliberations while aiding clinicians in moderating overly-optimistic motivations. Regulators and industry should appreciate special challenges in progressive disorders, where doing nothing was equated with doing harm.