Spinal Muscular Atrophy Update in Best Practices: Recommendations for Treatment Considerations

Background and objectives: Spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by biallelic variants of the Survival Motor Neuron 1 gene (SMN1) that affects approximately 1 in 15,000 live births. Availability of 3 SMN-enhancing treatments for SMA has led to urgency to review how clinicians and patients use these treatments for SMA, while additional research and real-world data and experience are being collected. This work describes important factors to assist with decision-making for SMN-enhancing treatments.

Methods: A systematic literature review was conducted on SMN-enhancing treatments for SMA and related studies. A working group of American and European health care providers with expertise in SMA care identified barriers and developed recommendations through a modified Delphi technique with serial surveys and feedback through virtual meetings to fill gaps for information where evidence is limited. A community working group of an individual living with SMA and caregivers provided insight and perspective on SMA treatments and support through a virtual meeting to guide recommendations.

Results: The health care provider working group and the community working group agreed that when determining whether to start, change, add, or discontinue a treatment, essential considerations include patient and family/caregiver perspective, and treatment safety and side effects. When initiating treatment for patients newly diagnosed with SMA, important patient characteristics are age and Survival Motor Neuron 2 gene (SMN2) copy number. Furthermore, when initiating, changing, or adding treatment, current clinical status and comorbidities drive decision-making. When considering a medication or treatment plan change, unless there is an urgent indication, a treatment and associated patient outcomes should be monitored for a minimum of 6-12 months. When determining a treatment plan with an adolescent or adult with SMA, consider factors such as quality of life, burden vs benefit of treatment, and reproductive issues. Access to care coordination and interdisciplinary/multidisciplinary care are essential to treatment success.

Discussion: Sharing information about current knowledge of treatments and shared decision-making between health care providers and patients living with SMA and caregivers are essential to overcoming barriers to providing SMN-enhancing treatments.