Antisense oligonucleotide (TTR silencer) Pregnancy: There are no available data on use in pregnant women to inform a drug-associated risk of adverse developmental outcomes. Treatment leads to a decrease in serum vitamin A levels and vitamin A supplementation is advised; vitamin A is essential for normal embryofetal development but excessive levels are associated with adverse developmental effects, and the effect of supplementation on the fetus in the setting of reduced maternal serum TTR is unknown. No adverse developmental effects were observed when eplontersen or a mouse-specific surrogate was administered to mice prior to mating and throughout organogenesis (US labelling §8.1).

Eplontersen

Brand names: Wainzua, Wainua (US)

Eplontersen is an antisense oligonucleotide used to treat the polyneuropathy of hereditary transthyretin-mediated amyloidosis in adults.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 45 mg

Route: Subcutaneous injection into the abdomen or upper thigh; the back of the upper arm can also be used if a healthcare provider or caregiver administers the injection

Frequency: Once monthly

No UK SPC (eMC) record was fetched in this bundle — figures are from the US prescribing information for WAINUA (AstraZeneca, label date 2026-04-15) and must be verified against the UK SPC before use. Indication is polyneuropathy of hereditary transthyretin-mediated amyloidosis. MISSED DOSE: administer as soon as possible after a missed dose, then resume dosing at monthly intervals from the date of the most recently administered dose. ADMINISTRATION: each autoinjector and prefilled syringe contains a single 45 mg dose — administer the entire contents of one device. The autoinjector is intended for self-administration by patients or administration by caregivers after training; the PREFILLED SYRINGE must be administered by a healthcare provider (insert subcutaneously at approximately a 45 degree angle after gently pinching the skin; do not expel small air bubbles before administration). Remove from the refrigerator 30 minutes prior to injection to reach room temperature and do not use other warming methods. Inspect before use — the solution should appear colourless to yellow; do not use if cloudiness, particulate matter or discoloration is observed, or if the device has been dropped, damaged, tampered with or is past its expiry date. Do not inject into the area within 2 inches (5 cm) around the navel, or into skin that is red, warm, tender, bruised, scaly or hard; rotate the injection site with each injection. VITAMIN A: treatment leads to a decrease in serum vitamin A levels and vitamin A supplementation is advised for patients taking this product. PAEDIATRIC: safety and effectiveness in paediatric patients have not been established — verify any under-18 use against a children's formulary.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

None — the US label section 4 Contraindications reads 'None'

Side effects

Vitamin A decreased (most common, at least 9% of treated patients)
Vomiting (most common, at least 9% of treated patients)
Reduced serum vitamin A levels — a labelled warning; vitamin A supplementation is recommended

Clinical monograph

How it works

It is a ligand-conjugated antisense oligonucleotide that binds transthyretin messenger RNA in the liver, reducing production of both mutant and wild-type transthyretin protein.

Prescribing in practice

Reducing transthyretin lowers serum vitamin A, so vitamin A supplementation is recommended during treatment.
It is given by subcutaneous injection at regular intervals, including via a self-administration option.
Monitor for injection-site reactions and assess ongoing neurological status.

Monitoring

Monitor neurological function and nutritional status, with vitamin A supplementation and ophthalmic review if symptoms of deficiency arise.

Counselling the patient

Take the recommended vitamin A supplement as directed.
Report any visual problems, particularly difficulty seeing in dim light.
Injection-site reactions can occur; rotate sites and report any that are severe or persistent.

Evidence & guidelines

Efficacy in hereditary transthyretin-mediated polyneuropathy was demonstrated in the NEURO-TTRansform study showing reduced transthyretin and neurological benefit.

Reference: NICE TA evaluation; ESC amyloid cardiomyopathy guidance; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways