An updated cost-utility model for onasemnogene abeparvovec (Zolgensma®) in spinal muscular atrophy type 1 patients and comparison with evaluation by the Institute for Clinical and Effectiveness Review (ICER)

Cost-Effectiveness Analysis of Etranacogene Dezaparvovec Versus Extended Half-Life Prophylaxis for Moderate-to-Severe Haemophilia B in Germany

BACKGROUND AND OBJECTIVE

Haemophilia B is a rare genetic disease that is caused by a deficiency of coagulation factor IX (FIX) in the blood and leads to internal and external bleeding. Under the current standard of care, haemophilia is treated either prophylactically or on-demand via intravenous infusions of FIX. These treatment strategies impose a high burden on patients and health care systems as haemophilia B requires lifelong treatment, and FIX is costly. Etranacogene dezaparvovec (ED) is a gene therapy for haemophilia B that has been recently approved by the United States Food and Drug Administration and has received a recommendation for conditional marketing authorization by the European Medicines Agency. We aimed to examine the cost-effectiveness of ED versus extended half-life FIX (EHL-FIX) prophylaxis for moderate-to-severe haemophilia B from a German health care payer perspective.

METHODS

A microsimulation model was implemented in R. The model used data from the ED phase 3 clinical trial publication and further secondary data sources to simulate and compare patients receiving ED or EHL-FIX prophylaxis over a lifetime horizon, with the potential for ED patients to switch treatment to EHL-FIX prophylaxis when the effectiveness of ED waned. Primary outcomes of this analysis included discounted total costs, discounted quality-adjusted life years (QALYs), incremental cost-effectiveness, and the incremental net monetary benefit. The annual discount rate for costs and effects was 3%. Uncertainty was examined via probabilistic analysis and additional univariate sensitivity analyses.

RESULTS

Probabilistic analysis indicated that patients treated with ED instead of EHL-FIX prophylaxis gained 0.50 QALYs and experienced cost savings of EUR 1,179,829 at a price of EUR 1,500,000 per ED treatment. ED was the dominant treatment strategy. At a willingness to pay of EUR 50,000/QALY, the incremental net monetary benefit amounted to EUR 1,204,840.

DISCUSSION

Depending on the price, ED can save costs and improve health outcomes of haemophilia patients compared with EHL-FIX prophylaxis, making it a potentially cost-effective alternative. These results are uncertain due to a lack of evidence regarding the long-term effectiveness of ED.

Gene Therapy for Genetic Syndromes: Understanding the Current State to Guide Future Care

Gene therapy holds promise as a life-changing option for individuals with genetic variants that give rise to disease. FDA-approved gene therapies for Spinal Muscular Atrophy (SMA), cerebral adrenoleukodystrophy, β-Thalassemia, hemophilia A/B, retinal dystrophy, and Duchenne Muscular Dystrophy have generated buzz around the ability to change the course of genetic syndromes. However, this excitement risks over-expansion into areas of genetic disease that may not fit the current state of gene therapy. While in situ (targeted to an area) and ex vivo (removal of cells, delivery, and administration of cells) approaches show promise, they have a limited target ability. Broader in vivo gene therapy trials have shown various continued challenges, including immune response, use of immune suppressants correlating to secondary infections, unknown outcomes of overexpression, and challenges in driving tissue-specific corrections. Viral delivery systems can be associated with adverse outcomes such as hepatotoxicity and lethality if uncontrolled. In some cases, these risks are far outweighed by the potentially lethal syndromes for which these systems are being developed. Therefore, it is critical to evaluate the field of genetic diseases to perform cost-benefit analyses for gene therapy. In this work, we present the current state while setting forth tools and resources to guide informed directions to avoid foreseeable issues in gene therapy that could prevent the field from continued success.

Patient and Caregiver Outcomes After Onasemnogene Abeparvovec Treatment: Findings from the Cure SMA 2021 Membership Survey

INTRODUCTION

Onasemnogene abeparvovec (OA) is the only gene replacement therapy currently approved for spinal muscular atrophy (SMA) treatment. We sought to assess real-world patient and caregiver outcomes after OA treatment for SMA.

METHODS

Patients who received OA were identified from the 2021 Cure SMA Membership Survey. Those treated at 6-23 months of age were matched to non-patients treated with OA on the basis of age at the time of survey and survival motor neuron 2 gene copy number. Patient characteristics, motor milestones, and resource and supportive care use, as well as caregiver proxy-reported health-related quality of life (HRQOL), were described. Caregiver unmet needs and HRQOL were also assessed.

RESULTS

Of the 614 patients in the survey, 64 received OA, and 17 were matched with 28 non-OA-treated patients. In general, a greater percentage of OA-treated patients achieved various motor milestones, including 100% sitting without support and 58.8% walking with assistance. OA-treated patients also had numerically lower rates of hospitalization and surgery. None required tracheostomy with a ventilator. The rate of using oxygen or a breathing machine for more than 16 h was also lower for OA-treated patients. OA-treated patients had less frequent trouble swallowing. HRQOL was reported to be similar to non-OA-treated patients. Caregivers of OA-treated patients reported better patient mobility scores and less work impairment.

CONCLUSIONS

The study suggests that treatment with OA is associated with greater rates of motor milestone achievements and less resource and supportive care use for patients with SMA treated at 6-23 months of age in the real world. For caregivers, it may also potentially reduce unmet needs, improve HRQOL, and reduce work impairment.

Spinal Muscular Atrophy: A (Now) Treatable Neurodegenerative Disease

Spinal muscular atrophy (SMA) is a progressive disease of the lower motor neurons associated with recessive loss of the SMN1 gene, and which leads to worsening weakness and disability, and is fatal in its most severe forms. Over the past six years, three treatments have emerged, two drugs that modify exon splicing and one gene therapy, which have transformed the management of this disease. When treated pre-symptomatically, many children show normal early motor development, and the benefits extend from the newborn period to adulthood. Similar treatment approaches are now under investigation for rare types of SMA associated with genes beyond SMN1.

Economic evaluation of Motor Neuron Diseases: a nationwide cross-sectional analysis in Germany

BACKGROUND AND OBJECTIVES

Motor Neuron Diseases (MND) are rare diseases but have a high impact on affected individuals and society. This study aims to perform an economic evaluation of MND in Germany.

METHODS

Primary patient-reported data were collected including individual impairment, the use of medical and non-medical resources, and self-rated Health-Related Quality of Life (HRQoL). Annual socio-economic costs per year as well as Quality-Adjusted Life Years (QALYs) were calculated.

RESULTS

404 patients with a diagnosis of Amyotrophic Lateral Sclerosis (ALS), Spinal Muscular Atrophy (SMA) or Hereditary Spastic Paraplegia (HSP) were enrolled. Total annual costs per patient were estimated at 83,060€ in ALS, 206,856€ in SMA and 27,074€ in HSP. The main cost drivers were informal care (all MND) and disease-modifying treatments (SMA). Self-reported HRQoL was best in patients with HSP (mean EuroQoL Five Dimension Five Level (EQ-5D-5L) index value 0.67) and lowest in SMA patients (mean EQ-5D-5L index value 0.39). QALYs for patients with ALS were estimated to be 1.89 QALYs, 23.08 for patients with HSP and 14.97 for patients with SMA, respectively. Cost-utilities were estimated as follows: 138,960€/QALY for ALS, 525,033€/QALY for SMA, and 49,573€/QALY for HSP. The main predictors of the high cost of illness and low HRQoL were disease progression and loss of individual autonomy.

CONCLUSION

As loss of individual autonomy was the main cost predictor, therapeutic and supportive measures to maintain this autonomy may contribute to reducing high personal burden and also long-term costs, e.g., care dependency and absenteeism from work.

Cost-Effectiveness of Newborn Screening for Spinal Muscular Atrophy in England

INTRODUCTION

We sought to evaluate the cost-effectiveness of newborn screening (NBS) versus no NBS for 5q spinal muscular atrophy (SMA) in England.

METHODS

A cost-utility analysis using a combination of decision tree and Markov model structures was developed to estimate the lifetime health effects and costs of NBS for SMA, compared with no NBS, from the perspective of the National Health Service (NHS) in England. A decision tree was designed to capture NBS outcomes, and Markov modeling was used to project long-term health outcomes and costs for each patient group following diagnosis. Model inputs were based on existing literature, local data, and expert opinion. Sensitivity and scenario analyses were conducted to assess the robustness of the model and the validity of the results.

RESULTS

The introduction of NBS for SMA in England is estimated to identify approximately 56 (96% of cases) infants with SMA per year. Base-case results indicate that NBS is dominant (less costly and more effective) than a scenario without NBS, with a yearly cohort of newborns accruing incremental savings of £62,191,531 and an estimated gain in quality-adjusted life-years of 529 years over their lifetime. Deterministic and probabilistic sensitivity analyses demonstrated the robustness of the base-case results.

CONCLUSIONS

NBS improves health outcomes for patients with SMA and is less costly compared with no screening; therefore, it is a cost-effective use of resources from the perspective of the NHS in England.

Capturing the Impact of Constraints on the Cost-Effectiveness of Cell and Gene Therapies: A Systematic Review

OBJECTIVE

Decision-makers need to resolve constraints on delivering cell and gene therapies to patients as these treatments move into routine care. This study aimed to investigate if, and how, constraints that affect the expected cost and health consequences of cell and gene therapies have been included in published examples of cost-effectiveness analyses (CEAs).

METHOD

A systematic review identified CEAs of cell and gene therapies. Studies were identified from previous systematic reviews and by searching Medline and Embase until 21 January 2022. Constraints described qualitatively were categorised by theme and summarised by a narrative synthesis. Constraints evaluated in quantitative scenario analyses were appraised by whether they changed the decision to recommend treatment.

RESULTS

Thirty-two CEAs of cell (n = 20) and gene therapies (n = 12) were included. Twenty-one studies described constraints qualitatively (70% cell therapy CEAs; 58% gene therapy CEAs). Qualitative constraints were categorised by four themes: single payment models; long-term affordability; delivery by providers; manufacturing capability. Thirteen studies assessed constraints quantitatively (60% cell therapy CEAs; 8% gene therapy CEAs). Two types of constraint were assessed quantitatively across four jurisdictions (USA, Canada, Singapore, The Netherlands): alternatives to single payment models (n = 9 scenario analyses); improving manufacturing (n = 12 scenario analyses). The impact on decision-making was determined by whether the estimated incremental cost-effectiveness ratios crossed a relevant cost-effectiveness threshold for each jurisdiction (outcome-based payment models: n = 25 threshold comparisons made, 28% decisions changed; improving manufacturing: n = 24 threshold comparisons made, 4% decisions changed).

CONCLUSION

The net health impact of constraints is vital evidence to help decision-makers scale up the delivery of cell and gene therapies as patient volume increases and more advanced therapy medicinal products are launched. CEAs will be essential to quantify how constraints affect the cost-effectiveness of care, prioritise constraints to be resolved, and establish the value of strategies to implement cell and gene therapies by accounting for their health opportunity cost.

Gene Therapy for Spinal Muscular Atrophy (SMA): A Review of Current Challenges and Safety Considerations for Onasemnogene Abeparvovec (Zolgensma)

Spinal Muscular Atrophy (SMA) is a genetic disease that causes weakness and wasting in the voluntary muscles of infants and children. SMA has been the leading inherited cause of infant death. More specifically, SMA is caused by the absence of the SMN1 gene. In May 2019, the Food and Drug Administration (FDA) approved onasemnogene abeparvovec, SMN1 gene replacement therapy, for all children with SMA younger than two years of age, without end-stage weakness. The objective of the study is to review the safety and efficacy of a novel gene therapy, onasemnogene abeparvovec (Zolgensma), for SMA and assess current challenges for gene therapy. For this, we have conducted a literature search on PubMed, MEDLINE, and Ovid (2019 to 2022) in the English language using the terms SMA, onasemnogene, and gene therapy. The search included articles, websites, and published papers from reputable health organizations, hospitals, and global organizations dedicated to bringing awareness to Spinal Muscular Atrophy. We found the first gene therapy for SMA to be onasemnogene, directly providing the survival motor neuron 1 (SMN1) gene to produce the survival motor neuron (SMN) protein. Onasemnogene is approved by the Food and Drug Administration and has the added benefit of being a one-time dose. On the downside, a major side effect of this treatment is hepatotoxicity. There is substantial evidence that the efficacy of therapy is increased when administered early to children under three months of age. Therefore, we concluded that onasemnogene appears to be an efficacious therapy for younger pediatric patients with SMA type 1. Drug cost and potential hepatotoxicity are major concerns. Long-term benefits and risks have not been determined, but it is more cost-effective and requires less time of treatment compared to the other used drug, nusinersen. Therefore, the combined safety, cost, and effectiveness of onasemnogene abeparvovec make it a reliable treatment option for treating SMA Type 1.

Gene Therapy of Sphingolipid Metabolic Disorders

Sphingolipidoses are defined as a group of rare hereditary diseases resulting from mutations in the genes encoding lysosomal enzymes. This group of lysosomal storage diseases includes more than 10 genetic disorders, including GM1-gangliosidosis, Tay-Sachs disease, Sandhoff disease, the AB variant of GM2-gangliosidosis, Fabry disease, Gaucher disease, metachromatic leukodystrophy, Krabbe disease, Niemann-Pick disease, Farber disease, etc. Enzyme deficiency results in accumulation of sphingolipids in various cell types, and the nervous system is also usually affected. There are currently no known effective methods for the treatment of sphingolipidoses; however, gene therapy seems to be a promising therapeutic variant for this group of diseases. In this review, we discuss gene therapy approaches for sphingolipidoses that are currently being investigated in clinical trials, among which adeno-associated viral vector-based approaches and transplantation of hematopoietic stem cells genetically modified with lentiviral vectors seem to be the most effective.

The Practice of Experimental Neurotherapeutics in Neuromuscular Disease

PURPOSE OF REVIEW

The discipline of experimental neurotherapeutics targets the process and operation of translating scientific discoveries into new treatments for neurologic diseases and has been instrumental in the progression of many areas of neurology.

RECENT FINDINGS

From the US Food and Drug Administration (FDA) market approval of the first systemic in vivo gene therapy in neurology to multiple current gene-targeting therapeutics, monoclonal antibodies, and new drugs under development or approved in the last several years, the field of experimental neurotherapeutics has a presence in every neuromuscular clinic in the United States.

SUMMARY

This article provides an overview of experimental neurotherapeutics with guidance on the clinical trials landscape, using examples in the field of neuromuscular disease. It covers the regulatory framework, clinical trial methodology, and offers advice on common pitfalls encountered when embarking on a clinical trials program in the clinic.

Onasemnogene Abeparvovec: A Review in Spinal Muscular Atrophy

Onasemnogene abeparvovec (Zolgensma®) is a gene therapy approved for the treatment of spinal muscular atrophy (SMA). Administered as a one-time intravenous infusion, onasemnogene abeparvovec uses the adeno-associated virus vector to deliver a functional copy of the human survival motor neuron (SMN) gene to motor neuron cells. SMN1 encodes survival motor neuron protein, which is responsible for the maintenance and function of motor neurons. In clinical trials, onasemnogene abeparvovec improved event-free survival, motor function and motor milestone outcomes in patients with SMA, with these improvements maintained over the longer term (up to a median of ≈ 5 years). Onasemnogene abeparvovec was also associated with rapid age-appropriate achievement of motor milestones and improvements in motor function in children with pre-symptomatic SMA, indicating the benefit of early treatment. Onasemnogene abeparvovec was generally well tolerated. Hepatotoxicity is a known risk that can generally be mitigated with prophylactic prednisolone. In conclusion, onasemnogene abeparvovec represents an important treatment option for patients with SMA, particularly when initiated early in the course of the disease.

Systemically targeted cancer immunotherapy and gene delivery using transmorphic particles

Immunotherapy is a powerful tool for cancer treatment, but the pleiotropic nature of cytokines and immunological agents strongly limits clinical translation and safety. To address this unmet need, we designed and characterised a systemically targeted cytokine gene delivery system through transmorphic encapsidation of human recombinant adeno-associated virus DNA using coat proteins from a tumour-targeted bacteriophage (phage). We show that Transmorphic Phage/AAV (TPA) particles provide superior delivery of transgenes over current phage-derived vectors through greater diffusion across the extracellular space and improved intracellular trafficking. We used TPA to target the delivery of cytokine-encoding transgenes for interleukin-12 (IL12), and novel isoforms of IL15 and tumour necrosis factor alpha (TNF α ) for tumour immunotherapy. Our results demonstrate selective and efficient gene delivery and immunotherapy against solid tumours in vivo, without harming healthy organs. Our transmorphic particle system provides a promising modality for safe and effective gene delivery, and cancer immunotherapies through cross-species complementation of two commonly used viruses.

Onasemnogene abeparvovec for the treatment of spinal muscular atrophy

INTRODUCTION

Gene therapy for spinal muscular atrophy (SMA) represents a significant milestone in the treatment of neurologic diseases. SMA is a neurodegenerative disease that results in motor neuron loss because of mutations of the survival motor neuron 1 gene, which directs survival motor neuron (SMN) protein production. Onasemnogene abeparvovec, a one-time gene replacement therapy, delivers a functional transgene to restore SMN protein expression. Onasemnogene abeparvovec has demonstrated improved survival and motor milestone achievements for presymptomatic infants and patients with SMA type 1.

AREAS COVERED

This expert review describes the current state of gene therapy for SMA, reviews the mechanism of and clinical experience with onasemnogene abeparvovec, explains future efforts to expand applications of gene therapy for SMA, and provides context for developing gene therapy for other conditions.

EXPERT OPINION

Onasemnogene abeparvovec has demonstrated efficacy in clinical trials and, because of this, is a valuable treatment option for patients with symptomatic infantile SMA and those identified by newborn screening. Gene therapy is still in its infancy, and challenges and uncertainties associated with transgene delivery must be addressed. With ongoing development of vector technology, more specific tissue tropism, reduced "off-target" effects, and an enhanced safety profile will continue to evolve.

Systematic Literature Review to Assess Economic Evaluations in Spinal Muscular Atrophy (SMA)

BACKGROUND

Spinal muscular atrophy (SMA) is a rare, progressive neuromuscular disease that affects individuals with a broad age range. SMA is typically characterised by symmetrical muscle weakness but is also associated with cardiac defects, life-limiting impairments in respiratory function and bulbar function defects that affect swallowing and speech. Despite the advent of three innovative disease-modifying therapies (DMTs) for SMA, the cost of DMTs in addition to the costs of standard of care can be a barrier to treatment access for patients. Health Technology Assessment (HTA) decision makers evaluate the cost effectiveness of a new treatment before making a reimbursement decision.

OBJECTIVE

The primary objective was to conduct a systematic literature review (SLR) to identify the modelling approaches used in economic evaluations that assess current approved treatments in SMA, with a secondary objective to widen the scope and identify economic evaluations assessing other (non-SMA) neuromuscular disorders.

METHODS

An SLR was performed to identify available economic evaluations associated with any type of SMA (Type 1, 2, 3 and/or 4). Economic evaluations associated with other (non-SMA) neuromuscular disorders were identified but not further analysed. Electronic searches were conducted in Embase, MEDLINE, Evidence-Based Medicine Reviews and EconLit via the Ovid platform in August 2019, and were supplemented by searches of the grey literature (reference lists, conference proceedings, global HTA body websites and other relevant sources). Eligibility criteria were based on the population, interventions, comparators and outcomes (PICO) framework. Quality assessment of full publications was conducted with reference to a published checklist.

RESULTS

Nine publications covering eight unique studies met all eligibility criteria for inclusion in the SLR, including four conference abstracts, two peer-reviewed original research articles and three HTA submissions (conducted in Canada, the US and the UK). Evaluations considered patients with early infantile-onset (most likely to develop Type 1 or Type 2 SMA), later-onset SMA and both infantile- and later-onset SMA. Data for the identified economic models were collected from literature reviews and relatively short-term clinical trials. Several intent-to-treat clinical trial populations were used in the studies, which resulted in variation in cycle length and different outcome measures to determine clinical efficacy. The results of the quality assessment on the five full-text, peer-reviewed publications found that they generally provided clear descriptions of objectives, modelling methods and results. However, key decisions, such as choice of economic evaluation, model type and choice of variables for sensitivity analysis, were often not adequately justified.

CONCLUSIONS

This SLR highlights the need for economic evaluations in SMA to better align in modelling approaches with respect to (i) consistency in model structure and use of motor function milestones as health states; (ii) consensus on measuring quality of life to estimate utilities; (iii) consistency in data collection by registries; and (iv) consensus on SMA-type classification and endpoints that determine intervention efficacy. Future economic evaluations should also incorporate the review group critiques of previous HTA submissions relating to data inputs and approaches to modelling and should include patient data reflective of the SMA population being modelled. Economic evaluations would also be improved with inclusion of long-term efficacy and safety data from clinical trials and valid patient and caregiver utility data.

CRISPR/Cas-Based Gene Editing Strategies for DOCK8 Immunodeficiency Syndrome

Defects in the DOCK8 gene causes combined immunodeficiency termed DOCK8 immunodeficiency syndrome (DIDS). DIDS previously belonged to the disease category of autosomal recessive hyper IgE syndrome (AR-HIES) but is now classified as a combined immunodeficiency (CID). This genetic disorder induces early onset of susceptibility to severe recurrent viral and bacterial infections, atopic diseases and malignancy resulting in high morbidity and mortality. This pathological state arises from impairment of actin polymerization and cytoskeletal rearrangement, which induces improper immune cell migration-, survival-, and effector functions. Owing to the severity of the disease, early allogenic hematopoietic stem cell transplantation is recommended even though it is associated with risk of unintended adverse effects, the need for compatible donors, and high expenses. So far, no alternative therapies have been developed, but the monogenic recessive nature of the disease suggests that gene therapy may be applied. The advent of the CRISPR/Cas gene editing system heralds a new era of possibilities in precision gene therapy, and positive results from clinical trials have already suggested that the tool may provide definitive cures for several genetic disorders. Here, we discuss the potential application of different CRISPR/Cas-mediated genetic therapies to correct the DOCK8 gene. Our findings encourage the pursuit of CRISPR/Cas-based gene editing approaches, which may constitute more precise, affordable, and low-risk definitive treatment options for DOCK8 deficiency.

Top Ten Tips Palliative Care Clinicians Should Know About Prognostication in Children

Pediatric palliative care (PPC) is different from palliative care (PC) for adults. However, conceptualizing PPC remains cumbersome due to the high heterogeneity of often rare diseases, the high diversity of disease trajectories, and the particular difficulty to predict the future of an individual, severely ill child. This article aims to provide an overview and critical reflection of different aspects of prognostication in children with PC needs. This includes different diseases from neurology to oncology, from the unborn baby to the young adult, new approaches in treatment, advance care planning, and, most important, communication with the affected child as well as parents.

A systematic review of moral reasons on orphan drug reimbursement

BACKGROUND

The number of market approvals of orphan medicinal products (OMPs) has been increasing steadily in the last 3 decades. While OMPs can offer a unique chance for patients suffering from rare diseases, they are usually very expensive. The growing number of approved OMPs increases their budget impact despite their low prevalence, making it pressing to find solutions to ethical challenges on how to fairly allocate scarce healthcare resources under this context. One potential solution could be to grant OMPs special status when considering them for reimbursement, meaning that they are subject to different, and less stringent criteria than other drugs. This study aims to provide a systematic analysis of moral reasons for and against such a special status for the reimbursement of OMPs in publicly funded healthcare systems from a multidisciplinary perspective.

RESULTS

With a systematic review of reasons, we identified 39 reasons represented in 243 articles (scientific and grey literature) for and against special status for the reimbursement of OMPs, then categorized them into nine topics. Taking a multidisciplinary perspective, we found that most articles came from health policy (n = 103) and health economics (n = 49). More articles took the position for a special status of OMPs (n = 97) than those against it (n = 31) and there was a larger number of reasons identified in favour (29 reasons) than against (10 reasons) this special status.

CONCLUSION

Results suggest that OMP reimbursement issues should be assessed and analysed from a multidisciplinary perspective. Despite the higher occurrence of reasons and articles in favour of a special status, there is no clear-cut solution for this ethical challenge. The binary perspective of whether or not OMPs should be granted special status oversimplifies the issue: both OMPs and rare diseases are too heterogeneous in their characteristics for such a binary perspective. Thus, the scientific debate should focus less on the question of disease prevalence but rather on how the important variability of different OMPs concerning e.g. target population, cost-effectiveness, level of evidence or mechanism of action could be meaningfully addressed and implemented in Health Technology Assessments.

Nusinersen: A Review in 5q Spinal Muscular Atrophy

Survival motor neuron 1 (SMN1), located on chromosome 5q, encodes the survival motor neuron (SMN) protein. A deletion or mutation in SMN1 results in a rare neuromuscular disorder: 5q spinal muscular atrophy (SMA). In such patients, SMN protein production relies solely on SMN2. Nusinersen (Spinraza^®) is a modified antisense oligonucleotide approved for the treatment of 5q SMA. Administered intrathecally, it modifies SMN2 pre-messenger RNA splicing, thereby increasing full-length SMN protein levels. Interim analyses from an ongoing phase II study suggest substantial clinical benefits with nusinersen initiation in presymptomatic patients. In phase III studies, nusinersen achieved significant and/or clinically relevant improvements in motor function in symptomatic patients with infantile- and later-onset 5q SMA, and significantly improved event-free survival and overall survival in patients with infantile-onset 5q SMA. Longer term (up to a median of ≈ 6 years of available data), motor function was maintained or improved in symptomatic patients. Nusinersen had a favourable safety profile in clinical studies in presymptomatic and symptomatic patients. Real-world experience supports the effectiveness, safety and tolerability of nusinersen in symptomatic patients of all ages. Thus, nusinersen remains an important treatment option among a broad range of 5q SMA patients.