Editorial: Spinal Muscular Atrophy: Evolutions and Revolutions of Modern Therapy

Neuromuscular disorders in the omics era

Neuromuscular disorders encompass a spectrum of conditions characterized by primary lesions within the peripheral nervous system, which include the anterior horn cell, peripheral nerve, neuromuscular junction, and muscle. In pediatrics, most of these disorders are linked to genetic causes. Despite the considerable progress, the diagnosis of these disorders remains a challenging due to wide clinical presentation, disease heterogeneity and rarity. It is noteworthy that certain neuromuscular disorders, once deemed untreatable, can now be effectively managed through novel therapies. Biomarkers emerge as indispensable tools, serving as objective measures that not only refine diagnostic accuracy but also provide guidance for therapeutic decision-making and the ongoing monitoring of long-term outcomes. Herein a comprehensive review of biomarkers in neuromuscular disorders is provided. We highlight the role of omics-based technologies that further characterize neuromuscular pathophysiology as well as identify potential therapeutic targets to guide treatment strategies.

Therapeutic Decision-Making Under Uncertainty in the Management of Spinal Muscular Atrophy: Results From DECISIONS-SMA Study

Introduction

There are many uncertainties about treatment selection and expectations regarding therapeutic goals and benefits in the new landscape of spinal muscular atrophy (SMA). Our aim was to assess treatment preferences and expectations of pediatric neurologists caring for patients with SMA.

Methods

DECISIONS-SMA is a non-interventional, cross-sectional pilot study that assessed pediatric neurologists with expertise in SMA from across Spain. Participants were presented with 11 simulated case scenarios of common encounters of patients with SMA type 1 and 2 to assess treatment initiation, escalation, or switches. We also asked for the expected benefit with new therapies for four simulated case scenarios. Participants completed a behavioral battery to address their tolerance to uncertainty and aversion to ambiguity. The primary outcome was therapeutic inertia (TI), defined as the number of simulated scenarios with lack of treatment initiation or escalation when warranted over the total (11) presented cases.

Results

A total of 35 participants completed the study. Participants’ mean (SD) expectation for achieving an improvement by starting a new therapy for SMA type 1 (case 1, a 5-month-old) and SMA type 2 (case 6, a 1-year-old) were both 59.6% (± 21.8), but declined to 20.2% (± 12.2) for a case scenario of a 16-year-old treatment-naïve patient with long-standing SMA type 2 with severe disability. The mean (SD) TI score was 4.2 (1.7), and 3.29 (1.5) for treatment initiation. Of a total 385 individual responses, TI was observed in 147 (38.2%) of treatment choices. The multivariable analysis showed that lower aversion to ambiguity (p = 0.019) and lower expectation of treatment response (p = 0.007) were associated with higher TI after adjustment for participants’ age and years of experience. Older age (p = 0.019), lower years of experience (p = 0.035), lower aversion to ambiguity (p = 0.015), and lower expectation of treatment benefits (p = 0.006) were associated with inertia for treatment initiation.

Conclusions

Pediatric neurologists managing patients with SMA were optimistic regarding treatment improvement in cases with early diagnosis, but had lower expectations when treatment delays and advanced patient age were present. Low aversion to ambiguity, low expectation of treatment benefits, and lower clinical experience were more likely to make suboptimal decisions, resulting in lack of treatment initiation, escalation, and TI.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00366-4.

Therapeutic decisions under uncertainty for spinal muscular atrophy: The DECISIONS-SMA study protocol

Background

The therapeutic landscape for spinal muscular atrophy has changed in the last few years, encompassing respiratory/motor function and life expectancy benefits. However, physicians still have the challenge of tailoring individuals’ treatment to therapeutic goals, disease progression, patient/caregiver’s preferences, and personal experience to achieve an optimal risk/benefit balance. This study aims to provide insight into the preferred treatment choices of pediatric neurologists managing spinal muscular atrophy in their daily practice and to recognize behavioral factors that may influence decision-making.

Methods

This is a noninterventional, cross-sectional pilot study involving 50 pediatric neurologists managing spinal muscular atrophy in Spain. We designed an online platform that contains 13 simulated case scenarios of common presentations of patients with spinal muscular atrophy. The primary study outcome will be treatment preferences according to the percentages of participants who select treatment initiation when recommended, switch therapies when there is evidence of disease progression, and select treatment discontinuation when disease progression puts patients outside treatment recommendation (11 case scenarios). Secondary outcomes include therapeutic inertia prevalence (11 case scenarios), herding phenomenon prevalence (2 case scenarios), care-related regret prevalence (specific questions) and intensity (10-item Regret Intensity Scale), occupational burnout prevalence (nonproprietary single-item measure), and risk preferences (uncertainty test and risk aversion assessment).

Conclusions

The study findings will contribute to better understand relevant factors associated with therapeutic decisions of pediatric neurologists in spinal muscular atrophy, identifying treatment preferences and evaluating the role of behavioral aspects such as therapeutic inertia, herding, regret, and workplace burnout.

Design of a Non-Interventional Study to Validate a Set of Patient- and Caregiver-Oriented Measurements to Assess Health Outcomes in Spinal Muscular Atrophy (SMA-TOOL Study)

Introduction

There is a need to optimize the current clinical outcome measures in spinal muscular atrophy (SMA) incorporating patients’ and caregivers’ perspectives. The aim of this study is to evaluate the psychometric properties (validity, reliability and sensitivity to change) of a set of existing questionnaires and newly created items grouped in a “toolbox” to assess the impact of SMA on the physical, psychological and activities of daily living domains of the patient’s life.

Methods

This non-interventional, prospective study will be conducted at 12 neuromuscular clinics specialized in the management of patients with SMA in Spain. An expert panel of pediatric and adult neurologists, rehabilitation physicians, and a patient representative participated in the study design and selected key disease dimensions to explore and their respective measurements: mobility-independence, fatigue and endurance, pain, fatigability, breathing and voice, sleep and rest, and vulnerability. Patients aged 2 years or older with a confirmed diagnosis of 5q-autosomal recessive SMA (genetic confirmation of homozygous deletion or heterozygosity predictive of loss of function of the SMN1 gene) will be recruited.

Planned Outcomes

The development of robust outcome measures in collaboration with the patient community is essential to determine what is meaningful to patients and their caregivers. This study will provide us with a comprehensive set of tools to better capture the course of the disease and the response to treatments.