by Lauren Taylor from In The Cloud Copy
Spinal muscular atrophy or SMA is a disease that occurs due to loss of motor neurons, which are the nerve cells that help to control the body’s muscle movements. The loss of the nerve cells eventually leads to atrophy and muscular weakness. This is a genetic disease of which there are varying types, all with different severities. The types of SMA are differentiated based on severity, when symptoms typically appear, and the affected gene.
The SMN1 gene is the mutated gene in SMA types 0 to 4. The SMN1 gene is the gene that is essential for the survival of motor neurons, as it is responsible for providing direction to make the protein SMN. The SMN protein is necessary for the motor neuron to survive.
SMA type 1 is the most commonly diagnosed form of the disease. Patients with this type of SMA typically start exhibiting symptoms sometime between birth and six months of age. The most thorough way of diagnosing SMA is via DNA testing, although a muscle biopsy is sometimes employed as well. There is currently no known treatment for SMA and most infants do not survive past the age of two. Respiratory failure is the most common cause of death in these patients. Patients also exhibit eating difficulties, constipation, and reflux, among other symptoms.
Giving Hope to Families of SMA Type 1 Patients
Novartis announced recent data from the ongoing clinical trial for Zolgensma (STR1VE-EU) showing that patients with SMA type 1 were exhibiting remarkable benefits. Some of these benefits included sustained improvements in motor function, achievement of motor milestones, and event-free survival.
Zolgensma is given via a one-time, IV infusion and the hope is that it will halt motor neuron loss after the infusion. Patients enrolled in the STR1VE-EU study are showing incredible improvements in milestone achievement, meeting some milestones that had previously not been reached in the history of SMA type 1. Some patients enrolled in this study had more severe phenotypes than others, making these results even more exciting and promising.
Patients in the STR1VE-EU study were between the ages of 6.9 and 18.6 months of age. 65.6% of the patients enrolled achieved a motor milestone that was not previously observed in SMA type 1 natural history. Six of those patients could independently sit for greater than ten seconds, twenty patients achieved head control, eight patients mastered rolling from back to sides and one patient could crawl, stand, and walk with assistance. 65.6% of the patients achieved and sustained a score of greater than or equal to 40 points on the CHOP INTEND index, while 37.5% achieved a score of 50 or greater. Typically, untreated SMA patients rarely reach a CHOP INTEND score of greater than 40.
A great majority of the patients, 91.7% of them to be precise, who did not require ventilator support at baseline, remained free of ventilator support or used prophylactic BiPAP for acute reasons during the study. 66.7% of participants were able to eat orally without any form of feeding support.
Overall, findings from the study have shown positive results. Zolgensma works to treat the root genetic cause of SMA by giving the affected individual a functional copy of the SMN gene to stop the progression of the disease. Zolgensma is currently approved for use in the United States, Japan, Europe and Brazil, with hopes of regulatory approval in three dozen additional countries, including South Korea, Canada, Switzerland, Australia, and Israel.
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