WHY SPINRAZA? / HOW SPINRAZA WORKS

Works within motor neurons to increase
full-length SMN protein1

SPINRAZA® (nusinersen) is the first and only antisense oligonucleotide (ASO) for the treatment of SMA1-5

Designed to target a specific sequence on SMN2
pre-mRNA, SPINRAZA modifies splicing to increase exon 7 inclusion and
production of full-length SMN protein1,6

Mechanism of Action Delivered to the CNS Resource Download

By specifically targeting SMN2 to increase SMN protein, SPINRAZA works by targeting an underlying cause of CNS motor neuron loss in SMA1,7

  • SMA is a disease of the CNS leading to progressive weakness7,8
  • Individuals with SMA have a mutated SMN1 gene and rely only on the SMN2 gene to produce functional SMN protein7,8
  • However, the SMN2 gene by itself can only produce about 10% of the full-length, functional protein that is normally produced by SMN1 gene7,8
  • SPINRAZA is an ASO designed to target a specific sequence on the SMN2 gene pre-mRNA1
  • SPINRAZA binds to a sequence in the intron downstream of exon 7 in the SMN2 transcript to modify splicing1
  • Increasing exon 7 inclusion in SMN2 mRNA transcripts results in increased production of full-length SMN protein1

CNS, central nervous system; mRNA, messenger ribonucleic acid; SMA, spinal muscular atrophy; SMN, survival motor neuron; SMN1, survival motor neuron 1; SMN2, survival motor neuron 2.

As an ASO, SPINRAZA is delivered directly to the CNS1,6

Intrathecal delivery concentrates nusinersen in the CSF
and bypasses the blood-brain barrier
Targets CNS tissues1,9
  • Distribution from the CSF to where motor neurons live
  • Nusinersen is delivered to motor neurons to increase production of full-length functional SMN protein
Prolonged half-life1
  • Continuous treatment approach
  • Long half-life in the CSF between prescribed doses
    • Half-life of up to 5.9 months (estimated to be 135-177 days)
Dosing independent of age or weight10
  • Drug exposure was relatively consistent in patients (age 8 days-15 years) based on pharmacokinetic data evaluated to support 12 mg dosing

CSF, cerebrospinal fluid.

Review the Warnings and Precautions,
including thrombocytopenia, coagulation
abnormalities, and renal toxicity1

SEE SPINRAZA SAFETY

SPINRAZA is approved for all ages—adults, teens, children, and infants1

SEE SPINRAZA SAFETY
Start your patient on spinraza

INDICATION

SPINRAZA® (nusinersen) is indicated for the treatment of spinal muscular atrophy (SMA) in pediatric and adult patients.

IMPORTANT SAFETY INFORMATION

Coagulation abnormalities and thrombocytopenia, including acute severe thrombocytopenia, have been observed after administration of some antisense oligonucleotides. Patients may be at increased risk of bleeding complications.

In the sham-controlled studies for patients with infantile-onset (Study 1) and later-onset (Study 2) SMA who received Low Dose Regimen (12 mg loading doses/12 mg maintenance doses), 24 of 146 SPINRAZA-treated patients (16%) with high, normal, or unknown platelet count at baseline developed a platelet level below the lower limit of normal, compared to 10 of 72 sham-controlled patients (14%). Two SPINRAZA-treated patients developed platelet counts <50,000 cells per microliter, with the lowest level of 10,000 cells per microliter recorded on study day 28. In patients who received High Dose Regimen (50 mg loading doses/28 mg maintenance doses), decreases in platelet counts were also observed.

Renal toxicity, including potentially fatal glomerulonephritis, has been observed after administration of some antisense oligonucleotides. SPINRAZA is present in and excreted by the kidney. In Study 1 and Study 2, 71 of 123 SPINRAZA-treated patients (58%) had elevated urine protein, compared to 22 of 65 sham-controlled patients (34%).

Laboratory testing and monitoring to assess safety should be conducted. Perform a platelet count, coagulation laboratory testing, and quantitative spot urine protein testing at baseline and prior to each dose of SPINRAZA and as clinically needed.

Severe hyponatremia was reported in an infant treated with SPINRAZA requiring salt supplementation for 14 months.

Cases of rash were reported in patients treated with SPINRAZA.

SPINRAZA may cause a reduction in growth as measured by height when administered to infants, as suggested by observations from the controlled study. It is unknown whether any effect of SPINRAZA on growth would be reversible with cessation of treatment.

The most common adverse reactions in the Low Dose Regimen (≥20% of SPINRAZA-treated patients and ≥5% more frequently than in control patients) that occurred in the infantile-onset controlled study were lower respiratory infection and constipation. Serious adverse reactions of atelectasis were more frequent in SPINRAZA-treated patients (18%) than in control patients (10%). Because patients in this controlled study were infants, adverse reactions that are verbally reported could not be assessed. The most common adverse reactions that occurred in the later-onset controlled study were pyrexia, headache, vomiting, and back pain. Post-lumbar puncture syndrome has also been observed after the administration of SPINRAZA.

The most common adverse reactions in the High Dose Regimen (≥10% of SPINRAZA-treated patients and ≥5% more frequently than control patients from Study 1) that occurred in patients with infantile-onset SMA were pneumonia, COVID-19, pneumonia aspiration, and malnutrition. COVID-19 was not discovered at the time of Study 1.

Please see full Prescribing Information.

References

1. SPINRAZA. Prescribing Information. Biogen; 2026. 2. U.S. FDA approves Biogen’s SPINRAZA™ (nusinersen), the first treatment for spinal muscular atrophy [press release]. Cambridge, MA: Biogen; December 23, 2016. Accessed March 19, 2026. https://investors.biogen.com/news-releases/news-release-details/us-fda-approves-biogens-spinrazatm-nusinersen-first-treatment 3. Evrysdi. Prescribing Information. Genentech; 2026. 4. Zolgensma. Prescribing Information. Novartis; 2025. 5. Itvisma. Prescribing Information. Novartis; 2025. 6. Chiriboga CA, Swoboda KJ, Darras BT, et al. Results from a phase 1 study of nusinersen (ISIS-SMNRx) in children with spinal muscular atrophy. Neurology. 2016;86(10):890-897. doi:10.1212/WNL.0000000000002445 7. Lunn MR, Wang CH. Spinal muscular atrophy. Lancet. 2008;371(9630):2120-2133. doi:10.1016/S0140-6736(08)60921-6 8. Darras BT, Royden Jones H Jr, Ryan MM, De Vivo DC, eds. Neuromuscular Disorders of Infancy, Childhood, and Adolescence: A Clinician’s Approach. 2nd ed. London, UK: Elsevier; 2015. 9. Podraza LC, Tadi P. Neuroanatomy, Motor Neuron. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan. Available from: https://ncbi.nlm.nih.gov/books/NBK554616/ 10. US Food and Drug Administration, Center for Drug Evaluation and Research. Medical Review: Spinraza (Application No. 209531Orig1s000). US FDA, 2017. https://www.accessdata.fda.gov/drugsatfda_docs/nda/2016/209531orig1s000medr.pdf. Accessed June 2, 2026. 11. Haché M, Swoboda KJ, Sethna N, et al. Intrathecal injections in children with spinal muscular atrophy: nusinersen clinical trial experience. J Child Neurol. 2016;31(7):899-906. doi:10.1177/0883073815627882

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