by Lauren Taylor from In The Cloud Copy
Spinal muscular atrophy or SMA is a disease that affects the patient’s central nervous system, peripheral nervous system, and skeletal muscles or voluntary movements. The nerve cells for muscle movement are mostly contained in the spinal cord. The loss of these nerve cells is what occurs in SMA, which results in the muscles not receiving the signals from the nerve cells, ultimately leading to muscular atrophy or the shrinking of the muscles as a result of them not being stimulated by the nerve cells.
SMA is caused by a deficiency of the motor neuron protein SMN. This protein is vital for the survival and function of normal motor neuron function. The deficiency of SMN occurs due to genetic variables or mutations on chromosome 5 in the SMN1 gene.
Symptoms of SMA range from mild to severe with the primary symptom being weakness of the muscles under voluntary control. In the most severe form of SMA (Type 1), children are very limited and struggle with sitting, feeding, breathing, and swallowing. Symptoms typically appear shortly after birth and many patients do not live past the age of 2. Types 2 and 3 both are milder forms of SMA and show symptoms slightly later in life. They are typically able to sit, sometimes, walk, and may even have a normal life expectancy. Type 4 is a very rare type that starts in adulthood and only causes mild symptoms.
Treatment for SMA has been minimal until recently. Prior, patients’ symptoms were treated, but there was not a lot of hope for any significant improvement. Recent developments have introduced a gene replacement therapy that gives the child a functional copy of the missing and/or defective gene in the cells.
Evrysdi (risdiplam) is another new treatment option that is showing promising results for patients affected by this horrible disease.
Two-Year Data Results on Evrysdi in Babies Shows Promise, Hope
PTC Therapeutics has developed a new medication to treat patients with SMA – Evrysdi or risdiplam. This therapy was recently approved (August 2020) for SMA patients that are two months or older. The trial so far demonstrated that patients were showing improved motor function and also reaching new milestones in development. Additional results showed that infants that were given therapeutic doses of risdiplam were alive and not requiring ventilation at the two-year mark.
Other milestones that were measured and showed improvements in year two included standing while supporting weight, upright head control, ability to turn over, and ability to sit without support for at least five seconds. During the study, thus far, there have not been any drug-related safety issues, signifying the safety of this drug.
The study is ongoing, with more than 450 patients currently enrolled. Patients range in age from birth to 60 years of age. Patients also vary in the symptom degree, from pre-symptomatic to those who have already received SMA therapies.
Evrysdi works by increasing and maintaining the production of the SMN protein. Evrysdi is an oral medication and can also be given via feeding tube. It is administered at home, which adds a level of convenience for families and patients. While the study is ongoing, it shows great hope and promise for the future of SMA patients and their families.
Learn more about this story here.