AMVUTTRA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AMVUTTRA (AMVUTTRA).
Amvuttra is an RNA interference (RNAi) therapeutic targeting transthyretin (TTR) mRNA. It binds to the 3' untranslated region of TTR mRNA, leading to its degradation via the RNA-induced silencing complex (RISC), thereby reducing hepatic production of both wild-type and mutant TTR protein. This reduces amyloid deposition in tissues.
| Metabolism | Metabolized via endocytosis and intracellular degradation into nucleotides; not metabolized by CYP450 enzymes. |
| Excretion | Primarily metabolized by endonucleases and exonucleases; unchanged drug is not excreted renally. Less than 1% of the dose is recovered in urine as intact patisiran. Fecal excretion accounts for less than 5% as metabolites. |
| Half-life | Terminal elimination half-life is approximately 3.2 days (range 2.5–5.2 days) based on population pharmacokinetic analysis, supporting every-3-week dosing. |
| Protein binding | Approximately 98% bound to plasma proteins, primarily to albumin and to a lesser extent low-density lipoprotein. |
| Volume of Distribution | Volume of distribution is approximately 0.26 L/kg (0.22–0.31 L/kg), indicating distribution predominantly within the vascular space. |
| Bioavailability | Not applicable for subcutaneous administration; bioavailability for subcutaneous injection is considered 100% relative to intravenous administration based on exposure equivalence. |
| Onset of Action | Reduction in serum transthyretin (TTR) levels is observed within 2–4 weeks after the first dose; clinical improvement in neuropathy (measured by modified Neuropathy Impairment Score +7) is evident at 9 months. |
| Duration of Action | Suppression of TTR production extends for the dosing interval of 3 weeks; TTR levels return toward baseline within 6–12 weeks after discontinuation. |
0.3 mg/kg (maximum 30 mg) subcutaneously once every 3 weeks
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for renal impairment; not studied in end-stage renal disease |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B); not studied in severe hepatic impairment (Child-Pugh C) |
| Pediatric use | Safety and efficacy in pediatric patients have not been established |
| Geriatric use | No specific dose adjustment recommended; limited data in patients ≥65 years |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AMVUTTRA (AMVUTTRA).
| Breastfeeding | It is unknown whether vutrisiran is excreted in human milk, but it is excreted in animal milk (rat studies). The M/P ratio has not been determined. Given the potential for adverse effects in the nursing infant, breast-feeding is not recommended during treatment and for at least 4 months after the last dose. |
| Teratogenic Risk | AMVUTTRA (vutrisiran) is an RNAi therapeutic targeting transthyretin (TTR). In animal studies, no adverse developmental effects were observed at doses up to 20 mg/kg in rabbits and 37.5 mg/kg in rats (approximately 14 and 27 times the human dose, respectively). However, placental transfer of the drug occurs in animals. As no human data are available, the risk cannot be excluded. During the first trimester, exposure may potentially affect embryogenesis; the drug should only be used if the benefit outweighs the risk. In the second and third trimesters, continuous exposure may affect fetal TTR levels, though TTR is not essential for fetal development. There are no data on peripartum effects. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
None.
| Precautions | ["Reduction of serum TTR levels may lead to reduced serum retinol (vitamin A) levels; patients should take vitamin A supplementation at the recommended daily allowance.","Risk of injection site reactions.","Risk of hypersensitivity reactions (e.g., facial edema, dyspnea)."] |
| Food/Dietary | No specific food restrictions. However, because AMVUTTRA can reduce serum vitamin A levels, patients should maintain a diet adequate in vitamin A (e.g., carrots, sweet potatoes, spinach) and may require supplementation under medical supervision to avoid deficiency. Avoid grapefruit as it may affect drug metabolism? (No known interaction; listed as precaution). Actually, no significant food interactions reported. |
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| Fetal Monitoring | Monitor maternal TTR levels and clinical symptoms of polyneuropathy during pregnancy. Periodic ultrasound monitoring for fetal growth and amniotic fluid volume is recommended due to unknown fetal effects. Also monitor maternal liver function and renal function, as pregnancy may alter drug clearance. No specific fetal heart monitoring is required. |
| Fertility Effects | Animal studies have not shown impairment of male or female fertility at clinically relevant doses. No human data exist. The drug targets TTR, which is not involved in reproductive processes; thus, no significant impact on fertility is anticipated. |
| Clinical Pearls | AMVUTTRA (vutrisiran) is an RNAi therapeutic indicated for polyneuropathy of hereditary transthyretin-mediated amyloidosis (hATTR) in adults. Administer subcutaneously every 3 months. Premedication is not required, but monitor for injection site reactions. No dose adjustment needed for mild or moderate renal impairment. Avoid in severe hepatic impairment (Child-Pugh C). Concurrent use with TTR stabilizers (e.g., tafamidis) has not been studied. Confirm TTR mutation by genetic testing before initiation. |
| Patient Advice | AMVUTTRA is given as an injection under the skin (subcutaneous) every 3 months by a healthcare professional. · Do not miss appointments; adherence to the dosing schedule is critical for effectiveness. · Common side effects include injection site redness, pain, or swelling; joint pain; and shortness of breath. · Report any signs of allergic reactions (hives, difficulty breathing) or worsening neuropathy symptoms. · Avoid pregnancy; use effective contraception during treatment and for 6 months after the last dose. · Inform your doctor about all medications, including over-the-counter drugs and supplements. · You may require regular monitoring of vitamin A levels as treatment can lower them; ensure adequate intake. |