Nusinersen

How it works

It modifies splicing of the SMN2 pre-mRNA to increase inclusion of exon 7, raising production of functional survival motor neuron protein.

Prescribing in practice

• It must be administered by intrathecal lumbar injection by clinicians experienced in the procedure, which carries risks of post-lumbar-puncture complications.
• Coagulation abnormalities and thrombocytopenia have been reported, so platelet count and coagulation should be checked before dosing.
• Renal toxicity is possible and urine protein should be monitored, as the drug is eliminated renally.

Monitoring

Monitor platelet count, coagulation parameters and urinary protein around each intrathecal dose, alongside motor function.

Counselling the patient

• Treatment involves repeated spinal injections including a loading schedule followed by maintenance doses.
• Report unusual bruising, bleeding or signs of infection after a procedure.
• Attend planned reviews to track motor milestones and response.

Evidence & guidelines

The ENDEAR trial demonstrated improved motor function and event-free survival with nusinersen in infantile-onset spinal muscular atrophy.