Novartis’ gene therapy for the rare disease spinal muscular atrophy is long-lasting as well as effective, suggests evidence that brings it even closer to the clinic.
Novartis trialed its gene therapy Zolgensma in 10 patients under six months of age, who had the genetic condition spinal muscular atrophy (SMA). In SMA type 1, the most common form, patients become unable to breathe or sit without help, and often die before four years of age. Four years after receiving Zolgensma, the patients were all alive and didn’t require permanent assistance to breathe.
“At the time we began the study, most babies with SMA type 1 would die or require permanent ventilation before age two,” stated Jerry Mendell, researcher at the Nationwide Children’s Hospital, USA. “Now with four years of data, we are seeing clear evidence of the potential of gene therapy to effectively, over several years, halt motor neuron loss and alter the course of SMA type 1 with a single dose.“
The study is a follow-up analysis after a two-year clinical trial that originally enrolled 15 patients. Of the 12 patients that received a therapeutic dose of the gene therapy in the original trial, 10 were enrolled in the follow-up study.
These findings add to those announced by the Swiss pharma earlier this month. In a phase III trial, 13 out of 15 (87%) SMA type 1 patients given Zolgensma when they were less than six months old didn’t need permanent help breathing when they were over a year old. In contrast, only 25% of untreated patients have this outcome.
Novartis is aiming to get FDA approval of the gene therapy later this month, and EMA approval later this year.
SMA is caused by a mutation in a gene that is crucial for keeping nerve cells healthy, causing them to die off. Obtained when Novartis acquired the US biotech AveXis in 2018, Novartis’ gene therapy consists of delivering a healthy copy of the mutated gene to the nerve cells, and stops them from dying.
If approved, Zolgensma will compete with Biogen’s drug Spinraza, which is approved to treat all types of SMA. However, a disadvantage of Spinraza is that it’s injected directly into the fluid surrounding the spinal cord every few months, which risks damaging the spinal cord. Zolgensma, on the other hand, is injected intravenously with just a single dose, which could mean fewer risks of spinal injury.
Genentech is also aiming to enter the SMA type 1 market soon with an oral drug. This drug is in phase III clinical testing.
One issue with Zolgensma will likely be pricing. Though the price isn’t set yet, Novartis claimed the therapy is worth between $4M and $5M, though seems to have recently dropped the price to around $2M. High prices are an ongoing trend for gene therapies, such as the example of Spark Therapeutics’ gene therapy for genetic blindness, Luxturna, with an initial asking price of €750,000 ($850,000) at launch in the US. Since the launch, Spark Therapeutics, and its European partner Novartis, implemented a scheme to refund the treatment’s cost if it wears off too early.
Another issue will likely be making the therapy profitable with such a small market. A lack of profitability was what led GSK to sell its gene therapy programmes to the UK-based Orchard Therapeutics last year, including the market-approved Strimvelis. The world’s first approved gene therapy, Glybera, was withdrawn completely by uniQure after it was used only once, and for a huge price tag of €890,000 ($1M).
Images from Shutterstock