Spinraza (nusinersen) is a prescription drug that treats spinal muscular atrophy (SMA) by increasing the level of a certain protein in your body. Your response to this drug may vary based on your medical history and diagnosis.
Spinraza contains the active drug nusinersen and belongs to a class of medications called antisense oligonucleotides, which doctors prescribe to treat SMA.
To understand Spinraza’s mechanism of action (how it works) we must first understand what SMA does in your body.
What happens with SMA
SMA is a rare genetic disorder that affects the central nervous system, which includes your spinal cord and brain. (A genetic disorder is a condition that causes changes to your DNA.)
Specifically, SMA is a type of motor neuron disease, which means it’s caused by problems with nerve cells that control muscle movement.
The survival motor neuron (SMN) protein helps nerve cells work correctly. People with SMA don’t have enough of this protein. Without enough SMN protein, nerve cells are unable to control muscle movements.
What Spinraza does
Usually, genes called SMN1 andSMN2 provide instructions for cells on how to make SMN. In people with SMA, these instructions are incomplete or missing.
Without enough SMN, nerve cells become damaged and die. Over time, this causes symptoms such as muscle weakness, muscle atrophy (wasting away of muscle), and difficulty breathing, swallowing, speaking, and walking.
Spinraza increases the level of SMN in your body by providing a missing piece in the instructions that tell your cells how to make SMN. This increased level of SMN in your body may reduce the SMA symptoms.
For more information about Spinraza’s mechanism of action, talk with your doctor, or visit the drug manufacturer’s website.
Spinraza starts working to treat SMA as soon as you receive the injection, but it will take a while for you to feel the drug’s effects.
In clinical studies, 56.8% of people given Spinraza showed a decrease in their SMA symptoms within 15 months of their first dose.
Talk with your doctor if you have questions about how long you can expect Spinraza to take to start treating your SMA symptoms.
Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.