Nusinersen

What it is and how it works

Mechanism of Action SPINRAZA is an antisense oligonucleotide (ASO) designed to treat SMA caused by mutations in chromosome 5q that lead to SMN protein deficiency. Using in vitro assays and studies in transgenic animal models of SMA, SPINRAZA was shown to increase exon 7 inclusion in SMN2 messenger ribonucleic acid (mRNA) transcripts and production of full-length SMN protein.

Indications

is indicated for the treatment of spinal muscular atrophy (SMA) in pediatric and adult patients. SPINRAZA is a survival motor neuron-2 (SMN2)-directed antisense oligonucleotide indicated for the treatment of spinal muscular atrophy (SMA) in pediatric and adult patients

Dosage and administration (summary)

is administered intrathecally Recommended Dosage The recommended dosage is one of two options: Low Dose Regimen: Administer one 12 mg loading dose every 14 days for three doses; then a fourth 12 mg loading dose 30 days after the third dose; then administer a 12 mg maintenance dose once every 4 months thereafter. High Dose Regimen: Administer one 50 mg loading dose followed by a second 50 mg loading dose 14 days later; then administer a 28 mg maintenance dose once every 4 months thereafter.

Contraindications

None. None.

Warnings and precautions

Thrombocytopenia and Coagulation Abnormalities: Increased risk for bleeding complications; testing required at baseline and before each dose and as clinically needed ( 5.1 , 2.3 ) Renal Toxicity: Quantitative spot urine protein testing required at baseline and prior to each dose ( 5.2 , 2.3 ) Thrombocytopenia and Coagulation Abnormalities Coagulation abnormalities and thrombocytopenia, including acute severe thrombocytopenia, have been observed after administration of some antisense oligonucleotides.

Pregnancy

Pregnancy Risk Summary There are no adequate data on the developmental risk associated with the use of SPINRAZA in pregnant women. When nusinersen was administered by subcutaneous injection to mice throughout pregnancy and lactation, developmental toxicity (long-term neurobehavioral impairment) was observed at all doses tested (see Data ) .

Storage and supply

Storage and Handling Store in a refrigerator between 2°C to 8°C (36°F to 46°F) in the original carton to protect from light. Do not freeze. SPINRAZA should be protected from light and kept in the original carton until time of use.

Source: Nusinersen (Spinraza) — US FDA prescribing information, 2026-03-31, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.