Inotersen

How it works

It is an antisense oligonucleotide that binds transthyretin messenger RNA and promotes its degradation, lowering production of both mutant and wild-type transthyretin protein.

Prescribing in practice

• It can cause severe thrombocytopenia and glomerulonephritis, so platelet count and renal function must be monitored regularly and the drug withheld for significant abnormalities.
• It is contraindicated where platelet counts are below the recommended threshold, and bleeding precautions apply.
• Vitamin A supplementation is generally recommended because transthyretin lowering reduces serum vitamin A.

Monitoring

Monitor platelet count and renal function (including urine protein) regularly throughout treatment to detect thrombocytopenia and glomerulonephritis early.

Counselling the patient

• Report any unusual bruising, bleeding, neck stiffness or rash promptly.
• Attend all scheduled blood and urine tests, which are essential for safety.
• Take any recommended vitamin A supplement as advised.

Evidence & guidelines

Inotersen efficacy in hereditary transthyretin amyloid polyneuropathy was demonstrated in the NEURO-TTR randomised controlled trial.