Patients with spinal muscular atrophy got an early Christmas present on Friday. The FDA approved nusinersen (Spinraza), making the drug the first-ever marketed treatment for the rare, potentially deadly genetic disorder.
Nusinersen is an injectable drug developed by Ionis Pharmaceuticals (NASDAQ: IONS) and partner Biogen (NASDAQ: BIIB), and is meant to slow the progression of the disease. The drug has been approved for both children and adults with SMA—meaning that patients with all forms of the disease are eligible for treatment.
“This is a landmark day for the SMA community with the first approved drug for the disease,” said Jill Jarecki, the research director of the nonprofit group Cure SMA, in a statement. “Cure SMA and our entire community have worked together tirelessly for more than thirty years to make this happen. It is important for all of us to stop and celebrate this shared accomplishment that will change and improve the lives of SMA patients.”
(Cure SMA drew about 4 percent of its $5.4 million in funding in fiscal 2015 from corporate supporters, some but not all of whom are drug makers. It also helped fund the nusinersen program in 2003 when it started out as research at the University of Massachusetts, before it was licensed to Ionis.)
The most common side effects seen in clinical studies of nusinersen were respiratory infections and constipation. The drug’s label, however, includes a warning about potential kidney damage or dangerously low blood-clotting platelets. Neurological side effects were seen in animal testing, but not human trials.
Biogen and Ionis haven’t disclosed how much nusinersen will cost as of yet, but the drug is likely to command a high price tag. Consensus estimates put a year of nusinersen at about $225,000 to $250,000 per patient, according to a research note from RBC Capital Markets analyst Michael Yee. The small populations of patients with rare or “orphan” diseases like SMA, and a lack of alternative treatments, means the drugs typically command very high prices—an estimated $111,820 per patient, per year between 2010-2014, according to a 2015 report from EvaluatePharma. Eteplirsen (Exondys 51), which earlier this year became the first ever approved drug for Duchenne muscular dystrophy, for instance, was priced at roughly $300,000 per patient, per year by its developer, Sarepta Therapeutics (NASDAQ: SRPT).
SMA is caused by a faulty version of the SMN1 gene, which doesn’t end up producing enough of the SMN protein to keep muscles strong. The disease affects about one out of every 10,000 newborns. There are four different forms of SMA, types 1 through 4, characterized by their severity and when they are diagnosed. Type 1 is the most severe and common form, diagnosed within six months of birth, and it can stop children from ever being able to walk or even sit; patients with this form of the disease often die within a few years due to complications such as respiratory problems. Type 3 SMA patients, by comparison, can live full lives, but may lose the ability to stand and walk.
Until today, there have been no approved drugs for SMA; nusinersen has become the first. It’s an RNA-based drug meant to help boost production of the SMA protein, which in turn is supposed to help improve patients’ motor function.
Biogen and Ionis initially reported positive data from a trial in infants with type 1 SMA in August. In that study, 40 percent of the 82 patients treated with nusinersen and eligible for analysis saw an improvement in achieving motor milestones—things like rolling, crawling, or standing—compared to none of the infants on placebo.
A few months later, the two companies reported data from a study in patients with later-onset, Type 2 SMA. That positive result is important, because it has enabled Biogen and Ionis to secure a broad label—the “broadest possible label, with no restrictions,” according to Cure SMA’s statement—for the drug.
About 25,000 people in the U.S. have SMA, and a majority of those diagnosed every year have Type 1. Patients with Type 2 SMA—diagnosed between 6 months and two years of age, as opposed to in infancy—have a better prognosis than Type 1 patients. Type 2 patients, for instance, might not be able to walk, but they can sit upright, function with the help of a wheelchair, and live longer. Because their prognosis is better, there are more to be treated with nusinersen, a chronic therapy infused into the fluid surrounding the spinal cord. Evercore ISI analyst John Scotti wrote in a research note recently that an estimated 2,500 patients in the U.S., Europe, and Japan have Type 1 SMA, while about 10,000 in those countries have Type 2.
Biogen and Ionis have received a rare pediatric disease priority review voucher for winning FDA approval of nusinersen. These vouchers are awarded to companies that bring treatments to market for neglected tropical diseases and rare pediatric ailments, and enable a swifter FDA review once a company files for approval of a drug. Vouchers have been sold for as much as $350 million over the past few years, as they can add millions in revenue for a company, or give a drugmaker a leg up over a competitor with a rival therapy.
Biogen obtained worldwide rights to nusinersen in August through a partnership deal with Ionis. Check out this story for more on nusinersen, SMA drug therapies, and the patient community’s involvement with the drug’s development.