Amvuttra (vutrisiran) is a prescription medication used to treat transthyretin-mediated amyloidosis, a rare and progressive disease in which a misfolded protein builds up in organs and tissues throughout the body. It is FDA-approved for two specific forms of this disease: the nerve damage (polyneuropathy) caused by the hereditary form, and the heart damage (cardiomyopathy) caused by either the hereditary or age-related form. It works by stopping the liver from producing the problem protein in the first place.
The Disease Amvuttra Treats
Transthyretin amyloidosis, often shortened to ATTR amyloidosis, happens when a protein called transthyretin becomes unstable and clumps into deposits called amyloid. Normally, transthyretin carries vitamin A and thyroid hormone through the bloodstream. But when this protein misfolds, it accumulates in nerves, the heart, and other tissues, gradually interfering with their function.
There are two types. The hereditary form (hATTR) is caused by a genetic mutation passed down in families and can affect both the nerves and the heart. It often appears between the ages of 30 and 70, though timing varies by mutation. The wild-type form (wtATTR) is not inherited. Instead, the normal transthyretin protein becomes unstable with age and deposits primarily in the heart. Wild-type ATTR cardiomyopathy mostly affects men over 60 and is increasingly recognized as a cause of heart failure in older adults.
Two Approved Uses
Amvuttra carries FDA approval for two distinct indications in adults. The first is polyneuropathy of hereditary ATTR amyloidosis, where amyloid deposits damage peripheral nerves. This causes numbness, tingling, and pain in the hands and feet, along with problems like digestive issues, dizziness upon standing, and difficulty walking as the disease progresses.
The second indication is cardiomyopathy from either hereditary or wild-type ATTR amyloidosis. In this form, amyloid deposits stiffen the heart muscle, making it harder for the heart to pump effectively. The FDA specifically approved Amvuttra for this use to reduce cardiovascular death, cardiovascular hospitalizations, and urgent heart failure visits.
How Amvuttra Works
Amvuttra uses a technology called RNA interference to shut down production of transthyretin protein at its source. The drug is a small piece of synthetic RNA that, once inside liver cells, targets and destroys the genetic instructions (messenger RNA) the liver uses to make transthyretin. With those instructions eliminated, the liver produces dramatically less of the protein, which means less misfolded protein is available to form new amyloid deposits.
This approach doesn’t remove amyloid that has already built up in tissues. But by cutting off the supply of new transthyretin, it slows or halts further accumulation, giving the body’s natural clearance mechanisms a chance to work. Patients on Amvuttra see substantial reductions in circulating transthyretin levels.
Evidence for Nerve Damage
The HELIOS-A trial tested Amvuttra in adults with hereditary ATTR polyneuropathy. After nine months, patients receiving the drug showed meaningful improvement in nerve function, while those on placebo continued to deteriorate. On a composite measure of nerve impairment, the Amvuttra group improved slightly from baseline (a 2.2-point decrease), whereas the placebo group worsened by 14.8 points, a gap of 17 points between the two groups.
Beyond nerve function scores, patients on Amvuttra also improved in quality of life, walking speed, nutritional status, and overall disability compared to placebo. For a disease that normally only gets worse over time, stabilization alone would be notable. Actual improvement across multiple measures was a strong result.
Evidence for Heart Disease
The HELIOS-B trial enrolled 655 patients with ATTR cardiomyopathy, including both hereditary and wild-type forms, and randomized them to Amvuttra or placebo for up to 36 months. The results showed Amvuttra reduced the risk of death from any cause by 36% compared to placebo. Cardiovascular death specifically was reduced by 33%.
The drug also had a clear impact on hospitalizations. Cardiovascular hospitalizations dropped by 25%, heart failure hospitalizations by 33%, and urgent heart failure visits by 46%. The combined risk of cardiovascular death and cardiovascular events was 28% lower in the Amvuttra group. These are meaningful reductions for a condition that carries a poor prognosis once heart failure develops. The effect on arrhythmia-related hospitalizations, however, was not statistically significant.
How It Is Given
Amvuttra is administered as a subcutaneous injection, meaning it goes just under the skin rather than into a vein. The dose is 25 mg once every three months. This dosing schedule is one of the drug’s practical advantages. An older RNA interference drug for the same condition, patisiran, requires an intravenous infusion every three weeks in a clinical setting. A single shot four times a year is considerably less disruptive to daily life.
A healthcare provider gives the injection, typically in the abdomen, upper arm, or thigh. Each dose comes in a prefilled syringe.
Side Effects and Vitamin A
The most common side effects reported more frequently with Amvuttra than placebo include joint pain, abdominal pain, shortness of breath, and decreased vitamin A levels. Most of these side effects were mild to moderate.
The vitamin A issue deserves specific attention because it is a direct consequence of how the drug works. Transthyretin is one of the main proteins that carries vitamin A in the blood. When Amvuttra suppresses transthyretin production, vitamin A levels drop as a side effect. In clinical trials, median vitamin A levels fell by about 61% in patients on Amvuttra. Despite this steep decline, actual symptoms of vitamin A deficiency were rare: night blindness, the hallmark sign, occurred in less than 1% of patients. Still, patients taking Amvuttra are advised to take a daily vitamin A supplement at the standard recommended amount.
It is worth noting that standard blood tests for vitamin A may not reflect what is actually available in tissues, since the measurement depends on the same transthyretin protein the drug suppresses. Your doctor may rely more on symptoms than lab values to assess vitamin A status while you are on this medication.
Who Is Eligible
Amvuttra is approved for adults with confirmed ATTR amyloidosis affecting the nerves, the heart, or both. Diagnosis typically involves a combination of genetic testing (for the hereditary form), imaging of the heart, and sometimes a tissue biopsy to confirm amyloid deposits. For the cardiomyopathy indication, both hereditary and wild-type patients are eligible.
Because ATTR amyloidosis is progressive and causes irreversible organ damage over time, earlier treatment generally leads to better outcomes. Patients who start treatment before significant nerve or heart damage has occurred tend to respond more favorably than those treated at advanced stages, though benefits have been observed across a range of disease severity in clinical trials.