FDA Approves Gene Therapy for Spinal Muscular Atrophy
FDA Approves Gene Therapy for Spinal Muscular Atrophy

FDA Approves Gene Therapy for Spinal Muscular Atrophy

At $2 million for a single dose, Novartis’s Zolgensma is the most expensive medicine to date, but still less expensive over a lifetime than another approved drug for the rare genetic disease.

Ashley Yeager

Ashley started at The Scientist in 2018. Before joining the staff, she worked as a freelance editor and writer, a writer at the Simons Foundation, and a web producer at...

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May 27, 2019


The US Food and Drug Administration has approved a new treatment for a rare childhood disorder that costs $2.125 million for single dose—the most expensive medicine on the market. 

The medicine is designed to treat spinal muscular atrophy (SMA), a condition driven by defects in the SMN1 gene, which causes afflicted babies to lose muscle control. The illness affects about 400 babies in the US each year and kills those with the most common form of the disease in just a few years. The new treatment is a gene therapy that uses genetically modified viruses to deliver healthy copies of the SMN1 gene to patients’ cells so they can generate a protein that helps the babies develop normally.

In tests of the treatment, babies who received it by 6 months of age didn’t have as severe muscle problems as those who didn’t get the drug. Infants getting the drug after six months also didn’t lose muscle control, but they suffered irreversible damage. Babies who got the treatment the earliest were the healthiest, according to the Associated Press.

“We saw just remarkable results for these kids,” David Lennon tells NPR. Lennon is the president of AveXis, the company, owned by Novartis that developed the drug, called Zolgensma. It is only the second FDA-approved gene therapy designed to treat a genetic disorder.

While the success of the treatment is being celebrated, the price tag is taking heat. “It's absolutely stunning,” Peter Bach, who studies health policy at Memorial Sloan Kettering Cancer Center in New York, tells NPR. The drug’s price tag, he says, drains resources from society, and it’s not alone. The first gene therapy, approved in 2017 and designed to treat a genetic condition that causes blindness, costs $425,000 for each eye. “We have been slowly subjected to price increases the same way the frog in the boiling water is slowly boiled to death,” Bach says.

The debate about the drug’s price began about a year ago, when Novartis released an estimate of what the treatment might cost—$5 million. In April, the US Institute for Clinical and Economic Review (ICER), an independent review agency, cited the estimated for Zolgensma as excessive. But on Friday (May 24), ICER announced that the launch price of roughly $2 million is reasonable, Reuters reports. 

“Zolgensma is dramatically transforming the lives of families affected by this devastating disease, and given the new efficacy data for the pre-symptomatic population, the price announced today falls within the upper bound of ICER’s value-based price benchmark range,” Steven Pearson, the president of ICER, tells STAT.

Zolgensma does have competition. There’s Biogen’s Spinraza, approved in late 2016, which requires regular spinal infusions costing $750,000 in the first year and $375,000 annually thereafter for life, potentially making it more expensive over the course of the child’s life than Zolgensma. Roche is also developing a pill taken daily to treat SMA, which could be on the market next year. 

At this point, “most families will want to do the gene therapy,” Russell Butterfield of the University of Utah in Salt Lake City who has received payments from Biogen for consulting, tells Reuters, “since it avoids the frequent spinal taps.” 

“You can look at this in either of two ways. It’s an amazing treatment and only a few kids will need it so a million here and million there is not worth more than shoulder shrug,” Bach tells STAT. “Or we have a big problem. Biopharma has been entirely redirected to rare diseases because the market will tolerate any price and the FDA will require pretty minimal data.”