Addressing the Global Disparities in Access to Treatment in Spinal Muscular Atrophy

ABSTRACT

The advent of novel disease‐modifying therapeutics for spinal muscular atrophy (SMA) increased life expectancy with better motor function and potentially better quality of life. While the benefits of these therapies are well established, most trials were conducted only in high‐income and middle‐income countries, and there is a lack of global representation. Furthermore, although these medications are now approved in over 50 countries worldwide, they remain unavailable to many who need them, potentially widening the gap in clinical care. Moreover, with these therapies, the standard SMA phenotype is changing, and the percentage of adult patients in the SMA cohort is increasing rapidly, requiring adjustments and modifications to the traditional therapeutic approach to SMA. It is important to identify potential sources of health inequalities to address them. Clinical opportunities for access include expanding screening availability by employing novel, affordable technologies, improving continuity of care through patient registries, and ensuring transitions of care for long‐term monitoring of adult patients with the disease. New technologies also offer the possibility of expanding the scope of telehealth to ensure access and of using artificial intelligence for rapid screening and disease monitoring. Regulatory changes and drug policies to reduce medication costs are also critical. Additional research on SMA population disparities and clinical trials that recruit from diverse populations and across the globe will help bridge the gap. Ensuring equitable healthcare access to disease screening and lifesaving medications is not just a recommendation but a call to action that can promote health for all.

1. Introduction

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease caused by a homozygous deletion or biallelic mutation in the survival motor neuron 1 (SMN1) gene, which encodes the SMN protein, a critical protein for spinal cord motor neuron function (Figure 1) [1, 2, 3]. The majority of patients are affected by the most severe type, SMA I, which, before the advent of disease‐modifying treatments (DMTs), used to have a median infant survival of 0.8 years, while the less severe intermediate type, SMA II, which affects 35% of patients, had a median survival of 10.9 years [4]. Direct healthcare costs for patients with infantile onset SMA are 50 times higher than those for non‐SMA controls [5, 6]. Standard of care management with the combination of multiple specialists—pediatric neurology, genetics, respiratory, physical, speech, and occupational therapists, nutrition, rehabilitation, and orthopedic specialists—has an estimated average cumulative direct medical cost of $935,570 per patient, with $2,393,250 for the most severe and eventually lethal form of the disease [4].

FIGURE 1.

Schematic representation of available disease‐modifying treatments (top panel) with current opportunities for improvement and targeted strategies for disparity mitigation in SMA care along different steps of the patients' journey (bottom panel).

Recently, three novel medications gained regulatory approval: the oligonucleotide nusinersen, the small‐molecule drug risdiplam, and the gene‐replacement therapies onasemnogene abeparvovec‐xioi (OA and OAV101 IT), which, through distinct mechanisms, increase SMN protein levels [1, 7]. By improving motor control and event‐free survival, and by reducing dependence on ventilation, among other outcomes, these novel SMA treatments have altered the natural history of the disease [8, 9, 10, 11, 12, 13, 14, 15, 16, 17]. They differ in administration routes, dosing frequency, and plasma availability: nusinersen is dosed intrathecally, usually with multiple doses, and primarily has cerebrospinal fluid (CSF) and central nervous system (CNS) availability, with lower plasma and systemic distribution [18, 19]. Risdiplam is administered orally, typically with multiple doses and broader systemic availability, including the CNS, muscles, and the abdomen [19]. Onasemnogene abeparvovec (OA) is given intrathecally or intravenously as a single dose, resulting in availability in multiple tissues beyond the CNS, predominantly the liver, muscles, and pancreas [19, 20].

The application of new technologies in detecting and treating diseases brings enormous opportunities; however, it can also widen healthcare inequalities. Nusinersen is currently approved in over 70 countries worldwide; OA in more than 50; and risdiplam in more than 100 [21, 22, 23]. While no definitive data exist, current estimates (collected from newborn screening availability data from national screening policies and SMA screening alliance data) suggest that 80% of the countries with access to all three medications are high‐ and middle‐income countries (Table 1). In Africa, as of 2023, only six countries had access to at least one medication, while the rest had no access or no data available [24]. Therefore, many infants, children, and adults do not have access to these medications, and significant disparities in accessibility exist [25]. Furthermore, many SMA patients will require long‐term care by multispecialty teams, and disparities in ongoing care as well as healthcare policy from a regional and global perspective need to be considered. Additionally, there is increasing awareness regarding the multisystemic nature of the disease, requiring development of a collaborative, long‐term framework to improve patient outcomes [26]. Here, we discuss the gaps in medication access and illustrate the health disparities SMA patients may encounter. We also propose actionable steps to mitigate treatment barriers and recommend strategies to ensure the standard of care for SMA patients worldwide. While the steps to accomplish such an important endeavor are numerous, we focus on a wide net of distinct approaches, with potential for immediate and long‐term applicability, including clinical opportunities, advocacy, regulatory steps, and research avenues.

TABLE 1.

Newborn screening, SMA clinical trials, and SMA drug availability based on the classification of World Bank income level classification of World Bank income level, SMA newborn screening availability, clinical trial participation and medication availability across different countries where trials on SMA were conducted.

Country	World Bank income level	SMN National program newborn screening availability	SMA trial participation	Nusinersen availability	Zolgensma availability	Risdiplam availability
US	H	Yes	Y (N Z R)	Yes	Yes	Yes
Canada	H	Yes	Y (N Z R)	Yes	Yes	Yes
United Kingdom	H	Partial	Y (N Z R)	Yes	Yes	Yes
France	H	Partial	Y (N Z R)	Yes	Yes	Yes
Italy	H	Partial	Y (N Z R)	Yes	Yes	Yes
Japan	H	Partial	Y (N Z R)	Yes	Yes	Yes
Taiwan	H	Yes	Y (N Z R)	Yes	Yes	Yes
Australia	H	Yes	Y (N Z R)	Yes	Yes	Yes
Israel	H	No*	Y (N Z R)	Yes	Yes	Yes
Saudi Arabia	H	No	Y (N Z R)	Yes	Yes	Yes
Turkey	UM	Yes	Y (N R)	Yes	No	Yes
Brazil	UM	Partial	Y (N Z R)	Yes	Yes	Yes
Chile	H	No	Y (N)	Yes	Yes	Yes
Mexico	UM	No	Y (N Z)	Yes	Yes	Yes
China	UM	No	Y (N Z R)	Yes	No (under review)	Yes
South Africa	UM	No	Y (Z)	Yes	Yes	Yes
Vietnam	LM	No	Y (Z)	No	No**	No (under review)
India	LM	No	Y (Z)	No**	Yes	Yes

Note: The data presented are not exhaustive. With the exception of South Africa, no additional clinical trial data were available from other African countries. Income level was defined based on country income classification based on the World Bank categories (when the trial was conducted).

Abbreviations: H, high‐income country; LM, lower‐middle‐income country; N, Nusinersen; R, Risdiplam; UM, upper‐middle‐income country; Z, Zolgensma.

^*Available carrier screening.

^**Available through humanitarian/global access programs.

2. Clinical Opportunities for Care

2.1. Newborn Screening

Newborn screening plays a crucial role in the timely diagnosis of SMA. Recent work, both from clinical trials and clinical practice data from the use of the three SMN‐enhancing medications, has led to a wider appreciation of the emergent nature of disease recognition and the need for timely treatment initiation [27]. Clinical trials in presymptomatic infants showed improved motor outcomes (standing, sitting, or walking without support), reduced need for ventilation, and, in some studies, avoided permanent ventilation and maintained body weight without artificial means, corroborating the importance of early and accurate disease detection [28, 29, 30, 31]. Early identification not only improves patient outcomes but also reduces costs compared to diagnosing the disease at a later, symptomatic stage [32]. This includes total final costs, hospitalization‐related costs, and nonmedical costs [32]. Additional favorable healthcare cost‐effectiveness for newborn screening in SMA includes incremental cost‐effectiveness ratios (ICERs) per quality‐adjusted life year (QALY) or life‐year earned, cost per QALY, or the total cost of savings [33, 34].

Across the world, there is limited availability of screening. Current estimates suggest that only 2%–11% of newborns worldwide are screened for this treatable disease [24, 32]. Recent research has highlighted disparities in screening rates across geographic regions. Most countries in North America and over 60% of European countries conduct SMA screening [35, 36, 37]. Conversely, in Asia, fewer than 10% of countries screen for SMA; notably, Taiwan and Qatar screen more than 90% of newborns, Japan screens about 30%, and China screens fewer than 10% [35, 36, 37]. In Australia, between 31% and 40% of newborns undergo screening, and while data from Africa and Latin America are limited, existing estimates suggest that screening remains infrequent without established national programs [35, 36, 37]. While newborn screening is available in all US states, practice varies by state, including the timing of evaluation by a specialized provider and the ordering of confirmatory tests [38]. Additionally, access to medications can vary by insurance status, with clinical restrictions based on ventilation status (present in 42% of states) and type of treatment; for example, Wisconsin limits eligibility for nusinersen to children who have not previously received treatment with OA, and Utah does not allow concurrent treatment with both nusinersen and OA [39, 40].

Given the importance of early detection and critical gaps in reliable testing, expanding testing availability can provide further opportunities for patient survival and care. As detecting gene transcripts with real‐time PCR (qPCR) is becoming affordable, expanding and implementing national‐level screening programs in developing countries is an attainable goal. Given that detection will need to be reliable, implementing quality control methods through cross‐continent scientific and laboratory collaborations will enable the transfer of “know‐how” for the technical parts of the detection, including appropriate test cut‐off values, validation of testing, and follow‐up of reporting [41]. To accomplish these tasks, strategic initiatives among key stakeholders are needed. Successful efforts from the infectious diseases field can serve as a blueprint for this goal. Collaborative partnerships among private and philanthropic organizations have provided critical resources and expanded human immunodeficiency virus (HIV) and tuberculosis (TB) testing worldwide [42, 43]. While differences among fields are expected, the basis of such partnerships and the opportunities they offer are promising. Lastly, as screening options for SMA become more widely available, careful consideration of available therapeutic options in that country would become critical. It would be important to consider the role of providers in providing adequate information to ethically inform patients' families of their options and to provide additional context to help them make informed decisions as they serve as surrogate decision‐makers for their children [44].

2.2. Drug Accessibility and Continuity in Clinical Care

Several aspects of medication approval and reimbursement can affect access to treatment. The socioeconomic status of the country and other factors, including healthcare financing models, may play a role. For example, in the European Union, the majority of drugs undergo cost‐effectiveness analyses [45]. While this model influences the drug price, it may also impact the approval of a drug in that country [46]. For SMA drugs, there are no major differences between approval in the US and EU, but Health Canada's approval for OA is limited to pediatric patients with specific SMN1 and SMN2 genotypes [47, 48].

Continuity in clinical care is another important step towards improving outcomes in SMA. SMA registries can play an important role in understanding the impact of new disease‐modifying medications beyond the scope of clinical trials. While access to care by neuromuscular specialists is limited even in developed countries, focused sharing of resources, not only within a country's borders but also through international collaborations, will enable ongoing follow‐up. Telehealth options allow areas that need more resources to access disease experts [49, 50]. However, telehealth is often limited by healthcare legislation and insurance policies, and amendments to these policies will be necessary to expand its reach. Primary healthcare workers serve as the backbone of community health in developing countries and can also help with ongoing clinical care for SMA patients through focused training [51]. Efforts to improve care and education by organizations that support SMA patients worldwide will be critical, including the work of Cure SMA, SMA Europe, the Muscular Dystrophy Association, and industry‐sponsored programs that provide patient and provider support. Large‐scale registries and nonprofit organizations can help capture the true burden of SMA worldwide and help monitor clinical response and healthcare disparities. Such efforts include but are not limited to Cure SMA, the Global SMA registry by Treat NMD in Europe, the NeuroMuscular Observational Research (MOVR) data hub by the Muscular Dystrophy Association, the Canadian Neuromuscular Disease Registry (CNDR), the International SMA Consortium (iSMAC), and RESTORE (NCT04174157), a US‐based registry supported by pharmaceutical companies, along with nonprofit organizations. Additional work should focus on clinical follow‐up, early symptom recognition, and management. Moreover, the application of artificial intelligence (AI) may enable rapid monitoring of SMA patients and direct them to appropriate health care, including assisting in diagnostics, such as assessing hypotonia using AI metrics or monitoring of disease progression and treatment response utilizing wearable sensors [52, 53].

Importantly, with a growing number of SMA patients living longer with the disease, a renewed focus is needed on adults with SMA, and transitions of care that focus on clinical continuity will become critical. In contrast to prior years, more than 50% of SMA patients are adults (Figure 2) [54, 55]. However, guidance regarding the needs and specialty care of this population is largely unavailable, with most information stemming from studies and guidelines focusing on children. This constitutes a major barrier to providing equitable care and formulating policies, and it becomes particularly important as the life expectancy of patients with SMA has increased with the advent of new therapies [26]. Some unique challenges the adult population faces include uncertainty during care transitions from pediatric to adult care, unique medical challenges compared to pediatric care, and limited access to coordinated, adult‐focused specialty care [55, 56]. Additionally, the medical needs of adults living with SMA are significantly different from those of children, with more prominent differences including the medical management of chronic pain and mental health challenges [57]. Therefore, ensuring access to specialists who can meet the needs of the adult SMA population is critical. For adult patients, a clear focus on physical health and emotional well‐being and the availability of care and home support networks, for example, through personal assistants or trained caregivers, is needed [56]. Similar to newborn screening and drug accessibility, there will be differences in public perception of the proposed interventions; therefore, the approach to new therapies is shaped by healthcare infrastructure across countries, and is not solely based on the socioeconomic status of the country. Prior work on how caregivers of patients with SMA approach decision making for novel therapies, includes focusing on the best interests of the child, burden of care and associated moral distress and parent agency [58]. Regional differences reflective of cultural and religious beliefs may impact adaptation to new therapies [59]. For example, in Botswana the perception and participation of gene‐editing medications can be influenced by cultural and ethical values, as well as fear of discrimination and trust [59].

FIGURE 2.

Schematic of race, ethnicity, and age representation in SMA cohorts. Data are summarized from SMA studies from the Cure SMA patient data in the “State of SMA, 2024” (panel A) and “State of SMA, 2022” and “State of SMA, 2024” reports (panel B) [48, 49].

2.3. Regulatory Changes

2.3.1. Drug Policies

Inequalities can become particularly prominent in the case of orphan drugs, which have high costs due to their targeted functions and, therefore, fewer indications compared to drugs that are more widely prescribed. These drugs can also have stricter regulatory approval prerequisites and often are burdened with lengthy reimbursement processes for patients [60]. Patent regulations limit accessibility—for pediatric diseases in particular, this problem can be exacerbated by pediatric exclusivity periods that provide extension in patent protection [61]. Additionally, the increasing trend of patent continuation approvals for brand‐name drugs will likely create additional roadblocks to accessibility. With the ratio of patients continuing brand‐name drugs increasing by 200% from 2000 to 2015, generic drugs are likely to take longer to reach the market, delaying drops in drug pricing, impeding affordability efforts, and resulting in increased healthcare costs [62]. Therefore, the elevated drug prices of nusinersen, OA, and risdiplam ought to be re‐examined. The potential of new medications to alter the course of a severe, lethal disease and to reduce the costs of care was a key factor in their approval in many countries. However, economic evaluation data question their cost‐effectiveness in healthcare systems, which impacts reimbursement decisions and, therefore, medication access [44, 63, 64]. Health‐related measures used to assess cost‐effectiveness include ICERs per QALY; higher ratios reflect the additional costs required for each extra QALY, and, beyond a certain threshold, are often considered not cost‐effective for health systems [44]. For example, in the US, the minimum ICERs per QALY for nusinersen are 709,000 USD and for OA, 157,000 USD, while the maximum acceptable ICER is 100,000–150,000 USD [44, 65]. Similarly, in Thailand, for patients with SMA I the minimum ICER for risdiplam is 158,357 USD, with maximum acceptable ICER 4444 USD [44, 66]. However, limitations of current evaluations include uncertainty about the long‐term efficacy of single‐dose drugs and the potential need for re‐dosing, methodological concerns in quantifying ICERs given the scarcity of data on long‐term quality‐of‐life metrics, and the unclear utility of combination regimens, which could affect demand and pricing estimates [44, 64]. Furthermore, there are limitations of the classic cost‐effectiveness analysis for rare diseases including the non‐exhaustive nature of QALY that lacks the ability to quantify disease‐specific states [67]. Additionally, the majority of available analyses are performed in high‐ and middle‐income countries with limited data available for low‐income countries [64, 66]. Therefore, further research on utilities (in QALYs), costs, and the comparative effectiveness of different treatments is necessary in order to understand their relative cost‐effectiveness. In fact, such analyses of other high‐cost drugs help ensure that negotiated prices more accurately reflect the medications' health benefits, supporting patient access, and facilitating price negotiations between health systems, such as between the Centers for Medicare and Medicaid Services and drug companies [68]. Lastly, additional approaches that could better fit the orphan drug evaluation such as the multicriteria decision analysis and “augmented” cost‐effectiveness analysis, can be helpful in better assessing the valuation of drugs for rare diseases [67]. Additional proposed steps regarding drug distribution, availability and clinical trials are discussed at the relevant sections.

2.3.2. Health Advocacy

Health policy and advocacy are important avenues that have historically provided critical mitigation strategies for healthcare disparities. Despite progress, many gaps exist. In an ever‐changing world, a renewed call for an updated plan and actions is required through policy and diplomacy. As the three disease‐altering treatments are approved in more countries worldwide, scientists, policymakers, and advocates should promote a “target SMA” cause and a collective effort to standardize treatments. Health policy efforts to promote drug donations and manufacturer‐sponsored programs could help close the gap. Successful examples from other diseases can serve as a basis for such initiatives, for example, in TB and HIV drug pricing [42, 69]. Since patenting exacerbates medication costs, easing patent regulations in countries with limited economic resources should be explored. Allowing for flexible intellectual property rules and creating platforms for technology transfer, as used in the past for vaccine access, are critical [70]. With more than 60 gene therapies projected to be approved by 2030, determining drug pricing across multiple axes, including socioeconomics, will be critical to ensuring fair pricing and access to therapy. Adaptable pricing strategies with restrictions that, for example, limit the ceiling to three times GDP per capita for a year of perfect health have been previously proposed [71]. This can enable value‐based pricing and increase access to novel therapeutics in low‐income countries [72]. While a unifying solution to this has yet to be identified, implementing alternative payment models, including amortization, performance‐based models, and risk‐spreading strategies, can pave the way toward this goal [73].

2.4. Research Directions

2.4.1. Characterizing the SMA Population Needs

Research on disparities in patients living with neurological disorders needs to be fostered. Spinal cord disorders are strikingly understudied, with research discussing race, social disparities, and racism in the bottom quartile, representing less than 2% of studies in neurological diseases [74]. In SMA, more than 70% of the studied subjects are white, with some ethnic and racial populations having less than 5% representation (Figure 2) [55]. While research on racial inequalities is increasing across a range of neurological disorders from stroke to epilepsy and muscular dystrophy, whether racial inequalities also contribute to the existing gaps in SMA patient care is unknown and an area of active research [74]. Such research can clarify the extent to which patient populations have reduced access to neurology specialists, delayed diagnosis, lower treatment availability, and increased disability. This will be a key element in better understanding the drivers behind disparities in SMA care and, therefore, better targeting the current needs of SMA patients.

Further research is also required to mitigate the gaps in adult healthcare. A complete picture of the evolving specialty needs of the adult SMA population, including mental health needs, is currently lacking [56]. Therefore, research is required to conduct a focused investigation to ensure that all patients living with the disease are adequately and appropriately cared for. Additionally, clinical trials studying newer DMTs in adults with SMA are sparse [55, 56]. Lastly, our insights into clinical outcomes and reliable biomarkers to quantify disease progression and treatment response have been inconclusive, requiring further research with intensified funding and a targeted research scope that reflects the unique needs of this population [56].

2.4.2. Clinical Trials

While clinical trials in SMA have recruited extensively across countries worldwide, the majority of patient recruitment and trial sites have been in North America and Europe (Table 1). No participation from African countries has been reported thus far. More than 80% of trials have taken place in high‐ or middle‐income regions, with minimal representation from low‐ and middle‐income countries (Table 1). This is not an isolated observation—a recent study investigating gene therapy trials in SMA, Huntington's disease, and Duchenne muscular dystrophy found that 99% of gene therapy clinical trials were conducted in high‐ and upper‐middle‐income countries [75]. Supporting research that recruits diverse populations and incentivizes projects from underrepresented minorities is a crucial next step. The diverse recruitment of SMA patients in trials can also reveal differences in clinical progression, clinical outcomes, and medication side effects across different populations. This can help with the generalizability of results and uncover heterogeneous effects. Therefore, ensuring that disparities are documented and actionable plans are put forward is paramount. This responsibility lies not only with researchers but also with the pharmaceutical companies sponsoring clinical trials. It is also critical that oversight boards and regulatory bodies, including pharmaceutical boards, universities, and the US Food and Drug Administration (FDA), ensure that recruitment is diverse. A national registry for black patients living with the disease, in alignment with similar efforts for patients with Parkinson's disease, multiple sclerosis, and stroke will contribute to this effort [76, 77, 78]. Lastly, engaging and including communities at both local and international levels through community‐based participatory research (CBPR) would represent significant steps towards inclusive and diverse SMA research.

3. Discussion

Novel SMN‐enhancing medications hold great promise in functional outcomes and quality of life but carry the risk of aggravating disparities. To prevent the worsening of existing gaps, there is a pressing need for renewed emphasis on ways to mitigate the disparities in SMA screening, management, and medication access. Lack of resources, including limited access to healthcare, diagnostics, and screening for early, presymptomatic detection, decreased availability of treatments, poor case follow‐up, and caregiver support, may contribute to increased mortality in babies born with the disease. However, it is unclear whether additional contributors exist within the US and internationally. Expanding our understanding of the drivers of disparities by investing in research on racial inequalities, geographic and socioeconomic disparities, and effective ways to address them is a priority.

Notably, emerging data indicate that SMA is increasingly recognized as a multisystemic disease [26]. Both animal studies and human data suggest that beyond nervous system impairment, the disease affects the skeletal muscles, bones, heart, vasculature, liver, and gastrointestinal tract [79]. Immune cell dysregulation has also been shown to occur, and at least to some extent, pro‐inflammatory responses are reduced with disease‐modifying therapies [80, 81]. Therefore, as SMA therapeutic strategies might evolve to include alternative approaches to address the systemic nature of the disease, it will be important to remain vigilant in addressing future care inequalities as well.

Even in the present state, the problem of healthcare disparities in caring for SMA patients appears daunting. However, we must recognize that this could present an opportunity to bring global forces together and create a sustainable platform for a better future. As more gene therapies become available and more debilitating diseases become curable or treatable, many countries will not have the necessary infrastructure to administer them safely. Gene therapies require rigorous monitoring as serious side effects may occur, including death. Even in high‐income countries, only a few tertiary care centers offer gene therapy. While we are far from having a global infrastructure for the safe administration of gene therapy, we can utilize SMA as a prototype to initiate global collaboration. Partnerships among community and non‐profit organizations, the public sector, and pharmaceutical companies will be instrumental to this effort. Efforts should be directed to modifying existing healthcare business plans, soliciting funding, changing healthcare regulations, and even international laws and regulations governing pharmaceutical development and drug pricing.

While the challenges ahead are significant, it is important to acknowledge that decision‐making and best practice updates for providers and patients continue to evolve. Nuanced decision‐making in the choice of medication, timing, and long‐term management exists, and our updated understanding of the effects of SMN‐enhancing treatments will further guide the field. Shared decision‐making, safety considerations, and patient characteristics, including age, SMN2 copy number, and current clinical status, should guide treatment selection [27]. As our knowledge in the field continues to grow and new challenges arise, it is critical that we remain vigilant and carefully re‐examine the needs and opportunities for patients worldwide. The road ahead will be long and difficult, but we must travel it to attain equitable healthcare for all.

Author Contributions

Basil T. Darras: conceptualization, writing – original draft, supervision, writing – review and editing. Charalampia Koutsioumpa: conceptualization, writing – original draft, writing – review and editing, data curation. Bhaskar Roy: conceptualization, writing – original draft, writing – review and editing, supervision. Robert C. Griggs: conceptualization, writing – original draft, supervision, writing – review and editing.

Disclosure

We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

Conflicts of Interest

B.T. Darras has served as an ad hoc scientific advisory board member for AveXis/Novartis Gene Therapies, Biogen, Sarepta, and Roche/Genentech; Steering Committee Chair/Member for Roche FIREFISH and MANATEE studies, and has received research support from Biogen, Novartis Gene Therapies (AveXis), and Roche/Genentech. R.C. Griggs reports grants from NIH, Muscular Dystrophy Association, and Patient Project for Muscular Dystrophy Support and others from PTC and Sarepta pharmaceuticals. B. Roy has been a consultant/advisor for Alexion (now part of AstraZeneca), Takeda, Sanofi, and argenx. Additionally, B.R. has received research support from the Martin Shubik Fund for IBM at Yale University, NIH, MDA, TMA, and clinical trial research support from Abcuro Pharmaceuticals, Immunovant, Takeda, and argenx. The other authors declare no conflicts of interest.

Data Availability Statement

Data sharing not applicable to this article as no datasets were generated or analysed during the current study.