Novartis has shared clinical trial results supporting the use of its one-time spinal muscular atrophy (SMA) gene therapy, Zolgensma (onasemnogene abeparvovec), in older and heavier children.
Affecting an estimated one in 10,000 infants globally, SMA is a rare, genetic neuromuscular disease and a leading genetic cause of infant death.
Caused by the lack of a functional SMN1 gene, the most severe forms of SMA result in the rapid and irreversible loss of motor neurons, affecting muscle functions such as breathing, swallowing and basic movement.
Zolgensma is the only gene therapy approved to treat SMA and the only treatment designed to directly address the genetic root cause of the disease.
The phase 3b SMART trial has been evaluating a one-time intravenous infusion of Zolgensma in paediatric patients who have symptomatic SMA with bi-allelic mutations in the SMN1 gene, any copy number of the SMN2 gene, and weigh between 8.5kg and 21kg.
Results showed that nearly all Zolgensma-treated patients maintained or improved motor milestones after 52 weeks, with most switching to Novartis’ therapy from another chronically administered disease-modifying therapy.
The majority of patients in the study experienced increases in transaminases and transient thrombocytopenia, Novartis said, adding that all cases were asymptomatic and managed with appropriate monitoring and treatment.
Dr Sandra Reyna, chief scientific advisor and head of global medical engagement for SMA at Novartis, said: “This data – the first Zolgensma open-label clinical study to include older and heavier, as well as previously-treated, patients – should build confidence among caregivers and healthcare professionals as they make informed treatment decisions, consistent with their local product label, for the studied patient population.”
The company said the results “supplement emerging real-world experience and use of [Zolgensma] in older and heavier children in countries where authorised use is not restricted by age”.
“The results from the SMART study provide evidence that Zolgensma is clinically beneficial for older and heavier patients with SMA, many of whom have had prior treatment with another disease-modifying therapy,” said Dr Hugh McMillan, paediatric neurologist.
“This data informs the use of Zolgensma in children up to 21kg, supporting the use of a one-time gene replacement therapy as a therapeutic option for SMA in a broader population,” McMillan added.