Novartis’ Expensive Gene Therapy for SMA Reasserts its Efficacy in Two Clinical Trials

On June 18th, Novartis announced the results of two Phase 3 clinical trials for Zolgensma, its expensive gene therapy against spinal muscular atrophy (SMA). Zolgensma is the most expensive drug on the market, costing $2.125 million per dose. However, the topline results in the STR1VE-EU and SPR1NT trials may prove its price is justified.

SMA is a genetic disorder that leads to death or forces patients to receive constant ventilation by the age of two. SMA is caused by a mutation or the deletion of the SMN gene. Zolgensma (onasemnogene abeparvovec) uses an adeno-associated viral (AAV) vector to deliver a copy of the SMN gene. 

Originally developed by AveXis, the drug was later acquired by Novartis for $8.7 billion. It was FDA-approved in 2019 but almost immediately became embroiled in a scandal. It was revealed that executives from AveXis personally manipulated or forced subordinates to manipulate data in studies involving mice. Additionally, Novartis was accused of not disclosing this issue with the FDA in a prompt manner. Nevertheless, the FDA maintained that it was confident that Zolgensma should remain on the market.

After the scandal, Novartis decided to rebrand AveXis and change the name to Novartis Gene Therapies.

Topline Results from Recent Trials

The efficacy of Zolgensma was tested in two Phase 3 clinical trials. SPR1NT, an open-label, single-arm, multi-center trial that enrolled patients younger than 6 weeks of age that had not yet developed symptoms of SMA. Results for this trial showed:

• 100% of patients survived without the need for a ventilator at 14 months of age.
• 100% of patients meet the primary endpoint of sitting independently for at least 30 seconds.
• 79% were within the normal development standard set by the World Health Organization.
• A significant number of patients showed similar development in motor skills compared to people their age that does not suffer from SMA.

The second clinical trial, STR1VE-EU, focused on investigating the efficacy of Zolgensma in patients that were already presenting symptoms. The results showed that 82% of patients achieved developmental motor skills beyond the skills observed in the natural progression of the disease. Additionally, the majority of patients remained free from ventilator support and delayed the need for a ventilator in a significant portion of the remaining patients. 

Shephard Mpofu, M.D., SVP, Chief Medical Officer, Novartis Gene Therapies summarized the results and their importance “When treated with Zolgensma before the onset of symptoms, not only did all patients survive but were thriving — breathing and eating on their own and sitting independently, with many standing and walking. When you consider these newborns would go on to develop severe symptoms of SMA Type 1, a devastating, progressive disease that robs children of the ability to talk, eat, sit up and even breathe, findings from the SPR1NT trial are nothing short of extraordinary.”

Related Article: Biogen Inks $120 Million Pact with High Flying Ginkgo Bioworks to Redefine Manufacturing of Gene Therapy Vectors

Author

Daniel Ojeda