Spinraza® was the first FDA-approved therapy to treat spinal muscular atrophy (SMA). It is an SMN-enhancing therapy that works by targeting the SMN2 gene, causing it to make more complete protein.

About Spinraza®

  • Spinraza® (nusinersen), marketed by Biogen, is FDA-approved for all ages and types of SMA.
  • Spinraza® is given via an intrathecal (IT) injection, which is an injection directly into the cerebrospinal fluid through the lower back. Individuals receive four “loading doses” within the first two months of treatment. Once those loading doses are completed, they receive a maintenance dose every four months for life.
  • Spinraza® is an antisense oligonucleotide. Antisense drugs are small snippets of synthetic genetic material that bind to ribonucleic acid (RNA), so they can be used to fix splicing errors in genes such as SMN2.
  • As with all treatments, timing is critical. Individuals who began Spinraza® as soon after diagnosis as possible had better results than those who waited to begin treatment.
  • Multiple SMA clinic sites across the U.S. are dosing individuals with Spinraza®. Many of these sites can be found on our map locator tool or by calling SMA360 at 1-844-477-4672.
  • SMA360 can also help with insurance and coverage of SPINRAZA, financial assistance, or treatment education.
  • To find insurance policies and payer information for Spinraza®, please click here.
  • Check out Biogen’s patient brochures on Spinraza® for infantspediatrics and adults and videos of children and adults taking Spinraza®.
  • For the most up-to-date prescribing information, see here.


Description Antisense oligonucleotide
Mechanism SMN2 mRNA splicing modifier
Approved age All
Dose 12 mg/five ml
How given Intrathecal bolus
How often Four loading doses over two months, then every four months
Body distribution Cerebral spinal fluid (Central only)
Warnings and precautions Increased risk for bleeding complications with low platelet count (thrombocytopenia) and coagulopathy, and kidney (renal) toxicity
Adverse reactions
  • Infantile onset SMA: lower respiratory infection, and constipation
  • Later-onset SMA: fever, headache, vomiting, and back pain
  • Blood and urine
Monitoring At baseline and prior to each dose:

  • Platelet count
  • Prothrombin time (PT)
  • Activated partial thromboplastin time (PTT)
  • Quantitative spot urine protein testing
Prescribing information See here

History of Spinraza®

From 2003 to 2006, Cure SMA provided the first research funding needed to begin investigation into this therapeutic approach. We would like to thank and acknowledge Cold Spring Harbor Laboratory (CSHL) and the University of Massachusetts Medical School for generating critical intellectual property for the program that was licensed to Ionis Pharmaceuticals.

After the pre-clinical work and early clinical testing was complete, Ionis Pharmaceuticals partnered with Biogen to launch a number of clinical trials testing Spinraza®. FDA approval of Spinraza® on December 23, 2016 was based on two double-blind, sham-procedure controlled clinical trials studying Spinraza® efficacy in symptomatic children with SMA and supported by open-label clinical trials conducted in pre-symptomatic and symptomatic patients with SMA.

The pivotal ENDEAR trial studied Spinraza® in symptomatic infantile onset SMA </= seven months of age in a multicenter, randomized, double-blind, sham-procedure controlled study. The interim analysis revealed that a statistically significantly greater percentage of patients achieved the definition of a motor milestone responder in the Spinraza® group (41%) compared to the sham control group (0%).

In the final analysis, 51% of patients in the Spinraza® group achieved the definition of a motor milestone responder compared to 0% of patients in the sham-control group. In addition, a 47% reduction in the risk of death or permanent ventilation was observed in the Spinraza® group (p=0.005). Additional clinical trials in later-onset SMA (CHERISH) also demonstrated efficacy. The pre-symptomatic clinical trial of Spinraza® (NURTURE) demonstrated motor milestone achievement and survival that exceeded prediction based on SMN2 copy number.

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