Gene therapy trial success: game changer for children with SMA

New research has shown that gene therapy may provide an effective treatment for Spinal Muscular Atrophy (SMA), a devastating and fatal genetic condition. The first part of the results from the SPR1NT trial were presented at the European Academy of Neurology (EAN) Conference recently. 

What is SMA?

SMA affects the motor nerve cells in the spinal cord, causing progressive muscle weakness and preventing babies from being able to roll, sit up, crawl, walk and eventually breathe. Until recently, it was the leading genetic cause of infant death in Australia, occurring in 1 in every 10,000 births.

Global recruitment site for trial

Sydney Children's Hospitals Network (SCHN) was the only Australian site selected to participate in the trial and was one of the largest global recruitment sites, with four patients enrolled from SCHN. The trial delivered by the Clinical Research Centre team at Sydney Children's Hospital, Randwick, investigated the use of Zolgensma, a novel viral vector-based gene replacement therapy. Fourteen infants, under six weeks of age and at risk of developing the most common and severe form of SMA, were treated before their symptoms started. 

Successful trial results

The study, which followed each participant until aged 18 months, found that all children achieved the ability to sit independently (with 78 per cent achieving this milestone within the normal developmental window), all were alive and free of permanent ventilation and all had normal swallow function and were fed exclusively by mouth by 18 months of age. The trial also showed that following treatment nine children were able to walk independently and all showed fine motor performance similar to babies without SMA by the completion of the study. 

Site-based lead for the study and Paediatric Neurologist at Sydney Children's Hospital, Randwick, A/Prof Michelle Farrar said the results of the trial was a potential game-changer for both clinicians and families affected by SMA. 

These results are extremely exciting and encouraging, not only are these children surviving but with this therapy, most are meeting the developmental milestones of any normal baby, which is unheard of.

Zolgensma works by treating SMA at its root cause, inserting a functioning copy of the defective gene into the cells.

By identifying these infants with SMA before the onset of symptoms, early results suggest we may have been able to take what was considered a lethal disease, and turn that around with a one-time, single dose infusion.

It is giving life back to these babies and hope back to their families.

Since the introduction of SMA into the newborn screening program in 2018, more than 200,000 babies have been screened, which has helped significantly with early identification of the condition. 

In addition to the newborn screening program, the NSW Government has invested $25 million to boost the state’s capability to manufacture viral vectors – the key components of this type of therapy which holds great promise for novel treatments for other genetic diseases.

The second part of the SPR1NT trial, which explored the effect of Zolgensma® in babies with milder SMA, is due to be presented later this year. 

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The SPR1NT trial was also supported by Luminesce Alliance and partners including UNSW Sydney