New Hope for Young Children with SMA - Early Treatment is Key

Mary Schroth, MD

No parent wants to hear their pediatrician give this diagnosis, “Your child has spinal muscular atrophy (SMA).” And yet, annually, approximately 1 in 11,000 babies are diagnosed with this serious and often life-threatening neuromuscular disease. SMA is the number 1 genetic cause of death for infants.

SMA is triggered by a mutation in the survival motor neuron gene 1 (SMN1). There are 4 types of SMA (I, II, III, and IV), with SMA type I being the most common and severe. The more severe the type of SMA, the earlier symptoms begin. SMA type I symptoms begin in the first 6 months of life.

In a healthy body, the SMN1 gene produces a protein critical to the function of the nerve cells that control muscles. Without it, those cells cannot properly function and eventually die, leading to debilitating and often fatal muscle weakness. This means, SMA can take away a child’s ability to walk, eat, or breathe, and, if not treated, may dramatically shorten life expectancy. The appearance of symptoms signals a significant loss of motor neurons. Predominate symptoms include hypotonia and weakness in the trunk and limbs. In the most severe cases, the respiratory muscles are compromised leading to respiratory insufficiency and failure.

Until recently, there has been little that health care professionals or parents could do, beyond offering supportive care, to improve outcomes for children living with SMA. But there is new hope.

Infants and toddlers diagnosed with SMA now have a fighting chance—a dramatically improved prognosis and quality of life thanks to a new, effective therapy and other promising treatments on the horizon.

In 2016, the FDA approved Spinraza^TM (nusinersen) that targets the underlying genetics of SMA, making it the first-ever FDA-approved therapy for SMA. Data from ENDEAR, a phase 3 sham-controlled trial that assessed the safety and efficacy of nusinersen in infants with SMA type I, showed that 51% of infants treated with nusinersen gained motor milestones, compared to none in the group that did not receive the drug. Timely treatment is key. Infants with a disease duration of ≤12 weeks showed greater improvements in motor function and motor milestones than untreated patients (75% vs. 0%; P <.0001).¹ In infants with disease duration greater than 12 weeks, the response rate still greatly favored the nusinersen treated group (32% vs. 0%; P = .0026) but at a lower rate.²

We know rapid response can dramatically save and improve a child’s life. The key is an urgent referral and swift diagnosis. Early treatment is essential, and best if applied within the first few weeks of disease onset, because motor neurons rapidly degenerate in the early progression of the disease.

Cure SMA, the leading nonprofit dedicated to the treatment and cure of SMA, recently launched SMArt Moves, a new disease awareness and educational campaign to empower pediatricians, other health care professionals, and parents to quickly recognize and diagnose the early signs of motor delays.

Central to the effort is an easy-to-use website, SMArtMoves.CureSMA.org, that encourages prompt action and a clear path forward for both health care professionals and parents should they suspect SMA or be concerned about motor delays. Specifically for health care professionals, on the site, there is a section detailing the most-up-to-date diagnostic criteria and educational tools including CMEs, offering insight from fellow practitioners and families, and sharing resources on the latest treatment options and protocols.

SMArt Moves makes it easy for health care professionals and parents to help spread the word about the importance of early identification and treatment by sharing these resources with their networks to change young children’s experience with this disease.

Early action and treatment can be truly life-changing. This swift action can result in positive results for so many with SMA. For example, a child receiving early treatment may soon be able to eat or breathe independently or reach important motor milestones previously unheard of for those with SMA.

Simply put, learning the SMA warning signs, taking early action, and getting early treatment can save, and dramatically improve, children’s lives.

Cure SMA introduced SMArt Moves during its symposium at the annual American Academy of Pediatrics Conference in Orlando and is generously funded by the members of the Cure SMA Industry Collaboration.

Mary Schroth, MD, is the chief medical officer at Cure SMA, the leading national non-profit dedicated to the treatment and cure of spinal muscular atrophy. She is also professor emeritus at the University of Wisconsin School of Medicine and Public Health. Prior to joining Cure SMA full-time, she spent 25 years as a pediatric pulmonologist specializing in SMA. The piece reflects her views, not necessarily those of the publication.Health care professionals and researchers interested in responding to this piece or contributing to MD Magazine® can reach the editorial staff here.

¹ De Vivo, DC; Bertini, E; Hwu, W-L; Foster, R; Bhan, I; Gheuens, S; Farwell, W; Reyna, SP. (2018, March). Nusinersen in Infants Who Initiate Treatment in a Presymptomatic Stage of Spinal Muscular Atrophy (SMA): Interim Efficacy and Safety Results from the Phase 2 NURTURE Study. Poster session presented at the Muscular Dystrophy Association Clinical Conference, Arlington, VA.

² Finkel, R., Chiriboga, C., Vajsar, J., Day, J., Montes, J., De Vivo, D., ... Bishop, K. (2015). Treatment of infantile-onset spinal muscular atrophy with nusinersen: A phase 2, open-label, dose-escalation study. Lancet, 388, 3017-3026. doi:https://doi.org/10.1016/S0140-6736(16)31408-8