Natalie Goedeker, Nurse Practitioner at Washington University School of Medicine in St. Louis, MO, discusses rapid initiation of risdiplam in newborns with spinal muscular atrophy (SMA).
SMA is a group of genetic neuromuscular disorders due to mutations along the SMN1 gene. The net result is atrophy of motor neurons that causes progressive muscle weakness and loss of movement. SMA mainly affects the muscles involved in walking, sitting, arm movement, and head control. Breathing and swallowing may also become difficult as the disease progresses. SMA type 1, 2, 3, and 4 relate to the severity of the condition and are linked to genetic changes in the SMN1 gene as well as the number of copies of the nearby related gene, SMN2. There are other rarer types of SMA caused by changes in different genes.
While widespread implementation of newborn screening for SMA has become common, treatment with approved therapies may be delayed. These delays are often caused by requirements for baseline and ongoing laboratory testing, intravenous or intrathecal dosing, and the complexities of procuring high-cost drugs. Additionally, those with two copies of SMN2 often have impaired motor development despite early treatment with these compounds.
Study
The objective of the study was to examine the effects of risdiplam in newborns with SMA and to determine if early intervention has an impact. . Risdiplam is a SMN2 pre-mRNA splicing modifier approved by the U.S. Food and Drug Administration (FDA) whose label was expanded in 2022 to include newborns. One advantage that risdiplam has over the other treatment options is that it can be given orally, instead of intrathecally, thereby allowing for an easier method to begin therapy.
The study included 29 infants, who started risdiplam at a median age of 9 days. All were alive without need for ventilatory or feeding support. One infant who was asymptomatic at treatment initiation declined over two months with areflexia, weakness, hypotonia, and a 25-point CHOP INTEND score decrease. However, all others showed progress in gross motor functions and/or improved CHOP INTEND scores. At an average of 2 months, 22 infants received other SMA therapies while all with two SMN2 copies continued to receive risdiplam in addition to another therapy.
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For more information on SMA and other rare musculoskeletal conditions, visit https://checkrare.com/diseases/musculoskeletal-diseases/
