Wainzua: Uses, Dosage & Side Effects

What Is Wainzua and What Is It Used For?

Wainzua contains the active substance eplontersen, a type of medicine known as a ligand-conjugated antisense oligonucleotide (ASO). Antisense oligonucleotides are short, synthetic strands of nucleotides designed to bind to a specific messenger RNA (mRNA) target inside cells. In the case of eplontersen, the target is the mRNA that encodes the transthyretin (TTR) protein. What makes eplontersen distinctive among ASOs is its conjugation to a triantennary N-acetylgalactosamine (GalNAc) moiety, a sugar-based ligand that facilitates highly targeted delivery to hepatocytes (liver cells) via the asialoglycoprotein receptor (ASGPR), which is abundantly expressed on the surface of liver cells.

Hereditary transthyretin-mediated amyloidosis (ATTRv amyloidosis, formerly known as familial amyloid polyneuropathy or FAP) is a rare, progressive, and potentially life-threatening genetic disease. It is caused by mutations in the TTR gene, which result in the production of an unstable, misfolded form of transthyretin protein. In healthy individuals, TTR is a protein produced primarily by the liver that circulates in the blood and serves as a carrier for thyroid hormone (thyroxine) and vitamin A (retinol, via binding to retinol-binding protein). When the TTR gene is mutated, the resulting abnormal TTR protein is prone to misfolding and aggregating into insoluble amyloid fibrils. These amyloid deposits accumulate progressively in peripheral nerves, the heart, the gastrointestinal tract, the kidneys, and other tissues, causing organ damage and dysfunction.

The polyneuropathy associated with ATTRv amyloidosis typically manifests as a progressive sensorimotor and autonomic neuropathy. Patients may initially notice numbness, tingling, or burning pain in the feet and hands, followed by progressive weakness and loss of sensation that advances from the extremities toward the trunk. Autonomic neuropathy can cause debilitating symptoms including orthostatic hypotension (blood pressure drops upon standing), gastrointestinal disturbances (diarrhea, constipation, nausea, early satiety), urinary dysfunction, and erectile dysfunction. If left untreated, ATTRv polyneuropathy leads to severe disability and is ultimately fatal, with a median survival of approximately 7 to 12 years from symptom onset, depending on the specific TTR mutation and the organs affected.

More than 130 different pathogenic TTR mutations have been identified worldwide. The most common mutation is Val30Met (also written as V30M), which is particularly prevalent in endemic areas such as northern Portugal, northern Sweden, and Japan. However, many other mutations exist and are found across diverse ethnic and geographic populations. The prevalence of ATTRv amyloidosis is estimated at approximately 10,000 to 50,000 affected individuals globally, making it a rare disease, though it is likely underdiagnosed due to the variability of its clinical presentation and the overlap of its symptoms with more common neuropathies.

Once inside hepatocytes, eplontersen hybridizes with TTR mRNA through complementary Watson-Crick base pairing. This mRNA-ASO duplex is recognized and cleaved by the intracellular enzyme RNase H1, leading to the selective degradation of TTR mRNA. By reducing the amount of TTR mRNA available for translation, eplontersen substantially decreases the production of both wild-type and all variant forms of TTR protein by the liver. This reduction in circulating TTR means there is less substrate available to misfold and form amyloid deposits, thereby slowing or halting disease progression. In clinical studies, eplontersen achieved mean reductions in serum TTR levels of approximately 80% or greater from baseline.

The pivotal clinical evidence for Wainzua comes from the NEURO-TTRansform study, a phase III, randomized, open-label trial that evaluated the efficacy and safety of eplontersen compared with a reference group receiving inotersen (a first-generation ASO targeting TTR) in adults with ATTRv polyneuropathy. The primary endpoint was the change from baseline in the modified Neuropathy Impairment Score +7 (mNIS+7), a composite measure of neuropathy severity. At 66 weeks, patients treated with eplontersen showed a statistically significant and clinically meaningful improvement in mNIS+7 scores, indicating stabilization or improvement of neuropathy, while also achieving superior TTR reduction. Eplontersen also demonstrated benefits on quality of life, as measured by the Norfolk Quality of Life–Diabetic Neuropathy questionnaire.

Wainzua was approved by the U.S. Food and Drug Administration (FDA) in December 2023 and subsequently by the European Medicines Agency (EMA) in 2024. It represents an important advancement over earlier treatments for ATTRv amyloidosis because it can be self-administered at home via a pre-filled pen, unlike some predecessors that required intravenous infusion in a healthcare setting or were associated with a more burdensome safety monitoring profile. Wainzua joins a growing therapeutic landscape for ATTR amyloidosis that includes TTR stabilizers (such as tafamidis and diflunisal), gene silencing agents (patisiran and vutrisiran), and liver transplantation.

What Should You Know Before Taking Wainzua?

Contraindications

The primary contraindication to Wainzua use is hypersensitivity (allergy) to eplontersen or to any of the other ingredients in the formulation. The excipients in Wainzua include sodium dihydrogen phosphate dihydrate, anhydrous disodium phosphate, sodium chloride, and water for injections. Hydrochloric acid and sodium hydroxide may be used to adjust pH. If you have a known allergy to any of these substances, you must not use Wainzua.

Before starting treatment, your doctor will perform a thorough assessment of your medical history, including any previous allergic reactions to medications. If you have a history of serious hypersensitivity reactions to antisense oligonucleotide therapies, discuss this with your healthcare provider, as cross-reactivity may be a concern.

Warnings and Precautions

Wainzua reduces the production of transthyretin (TTR), which serves as the main transport protein for retinol (vitamin A) in the bloodstream. By lowering TTR levels, Wainzua also reduces the blood’s capacity to carry vitamin A, potentially leading to vitamin A deficiency even if dietary intake is adequate. Your doctor will monitor your vitamin A levels before starting treatment and periodically thereafter, and will prescribe an appropriate daily oral vitamin A supplement.

Signs and symptoms of vitamin A deficiency that you should watch for include:

• Night blindness (nyctalopia): Difficulty seeing in low-light conditions or poor adaptation to darkness.
• Dry eyes (xerophthalmia): Persistent dryness, gritty sensation, or discomfort in the eyes.
• Blurred or cloudy vision: Changes in visual acuity or clarity that were not present before treatment.
• Eye inflammation: Redness, pain, excessive tearing, discharge, or a feeling of something in the eyes.

If you notice any problems with your vision or other eye symptoms while using Wainzua, inform your doctor promptly. Your doctor may refer you to an eye specialist (ophthalmologist) for a comprehensive examination. It is important to note that vitamin A levels may remain low for more than 15 weeks after the last dose of Wainzua, so monitoring and supplementation may need to continue even after treatment is stopped.

Pregnancy and Breastfeeding

The effects of Wainzua on human pregnancy have not been adequately studied. However, because Wainzua significantly lowers vitamin A levels in the blood, and vitamin A plays a critical role in normal embryonic and fetal development, the use of Wainzua during pregnancy poses a risk of vitamin A deficiency-related birth defects. Conversely, excessive vitamin A supplementation during pregnancy is also teratogenic (harmful to the developing fetus). For these reasons, women of childbearing potential must:

• Confirm that they are not pregnant before starting Wainzua treatment.
• Use effective contraception during the entire course of treatment.
• Inform their doctor immediately if they become pregnant during treatment.

If you plan to become pregnant, your doctor will advise you to stop Wainzua and vitamin A supplements. Your doctor will then monitor your vitamin A levels and ensure they have normalized before you attempt to conceive. If an unplanned pregnancy occurs during treatment, your doctor will instruct you to stop Wainzua immediately. During the first 3 months (first trimester) of pregnancy, your doctor may advise you to stop vitamin A supplements. However, because of the increased risk of vitamin A deficiency during the later stages of pregnancy, your doctor may advise resuming vitamin A supplementation during the last 6 months of pregnancy if your levels have not yet normalized.

It is not known whether eplontersen is excreted in human breast milk. A risk to the breastfed infant cannot be excluded. If you are breastfeeding or planning to breastfeed, discuss this with your doctor before starting treatment. Your doctor will help you weigh the benefits of breastfeeding against the benefits of Wainzua treatment.

Children and Adolescents

Wainzua should not be used in children or adolescents under 18 years of age. The safety and efficacy of eplontersen have not been established in the pediatric population. ATTRv amyloidosis very rarely presents in childhood, and treatment decisions for younger patients should be made on a case-by-case basis by specialists experienced in managing this condition.

Driving and Operating Machinery

Wainzua is not expected to affect your ability to drive or operate machinery. Based on its pharmacological properties and the known side effect profile, it is unlikely to impair cognitive or motor function. However, if you experience any visual disturbances related to low vitamin A levels (such as impaired night vision), you should exercise caution when driving, particularly at night, and inform your doctor.

Important Information About Ingredients

Wainzua contains less than 1 mmol (23 mg) of sodium per 0.8 mL dose, meaning it is essentially sodium-free. This is relevant for patients on a sodium-restricted diet. If you have any known intolerances or allergies to the excipients listed above, inform your healthcare provider before starting treatment.

How Does Wainzua Interact with Other Drugs?

One of the practical advantages of Wainzua is its favorable drug interaction profile. Unlike many traditional small-molecule drugs that are metabolized by hepatic cytochrome P450 (CYP) enzymes and can participate in complex drug-drug interactions, eplontersen is an antisense oligonucleotide that is metabolized through nuclease-mediated degradation pathways. It is not a substrate, inhibitor, or inducer of CYP enzymes, and it is not expected to affect the pharmacokinetics of other medications or to have its own pharmacokinetics affected by other drugs.

No formal drug interaction studies have been conducted with eplontersen. However, based on its mechanism of metabolism and clearance, no clinically significant pharmacokinetic interactions are expected. In clinical trials, patients receiving Wainzua were permitted to continue their existing medications, including common treatments for the symptoms and complications of ATTRv amyloidosis.

In clinical practice, patients with ATTRv amyloidosis often take multiple medications to manage the various manifestations of their disease. The following table summarizes the types of medications commonly used alongside Wainzua:

Although no formal drug-drug interactions have been identified, it is important to inform your doctor or pharmacist about all medications, supplements, and over-the-counter products you are currently using. This is standard practice for any prescription medication and supports comprehensive monitoring of your overall health and treatment outcomes.

A pharmacodynamic consideration worth noting is the potential for combining Wainzua with other TTR-lowering therapies (such as patisiran or vutrisiran, which are siRNA-based TTR gene silencers). While such combinations have not been formally studied, the theoretical concern is that combining two potent TTR-lowering agents could result in excessive TTR suppression and a greater risk of vitamin A deficiency. Any decision to combine TTR-targeted therapies should be made only by specialists experienced in managing ATTRv amyloidosis.

What Is the Correct Dosage of Wainzua?

Wainzua should always be used exactly as your doctor, pharmacist, or nurse has instructed. The medication is administered as a subcutaneous injection (under the skin) and is available in single-use pre-filled pens, each containing 45 mg of eplontersen (as eplontersen sodium) in 0.8 mL of solution. You and your doctor or nurse will decide whether you should inject Wainzua yourself, whether your caregiver should administer it, or whether a healthcare professional should give the injection.

Adults

The recommended dosage regimen is straightforward: one subcutaneous injection of 45 mg once per month.

Wainzua is injected subcutaneously into one of the following body areas:

• Abdomen (belly): Avoid the area approximately 5 cm (2 inches) around the navel.
• Front of the thighs: The upper part of the front of the thigh.
• Back of the upper arm: This site should be used only if the injection is given by a caregiver or healthcare professional. Do not attempt to inject yourself in this area.

Rotate injection sites between administrations and avoid injecting into skin that is tender, red, hard, damaged, bruised, or scarred. At each injection, choose a site that is at least 3 cm from the previous injection site.

Before first use, you or your caregiver will receive training from your healthcare team on the correct preparation and injection technique for the pre-filled pen. Always read the separate instructions for use carefully before each injection. The general steps include:

1. Preparation: Remove the carton from the refrigerator and allow the pre-filled pen to reach room temperature (20–25 °C) for 30 minutes. Do not heat it by any other means (e.g., microwave or warm water).
2. Inspection: Check the pen for damage and verify the expiration date. Inspect the solution through the viewing window: it should be clear and colorless to yellow. Small air bubbles are normal. Do not use the pen if the solution is cloudy, discolored, or contains visible particles.
3. Site preparation: Wash your hands thoroughly with soap and water. Clean the injection site with an alcohol swab or soap and water, and let it air dry.
4. Injection: Remove the cap by pulling it straight off. Place the orange needle guard flat against the skin at a 90-degree angle. Press down and hold for approximately 10 seconds until the orange plunger fills the viewing window. You may hear a first click when the injection begins and a second click when it ends.
5. Post-injection: Lift the pen straight up. The needle guard will slide down and lock over the needle automatically. Check the viewing window to confirm the full dose was delivered. If needed, apply gentle pressure with a cotton pad or gauze to the injection site.
6. Disposal: Place the used pen immediately into an approved sharps container. Do not dispose of it in household waste or attempt to reuse it.

Children and Adolescents

Wainzua is not recommended for use in patients under 18 years of age. Safety and efficacy have not been established in this age group.

Elderly Patients

No dose adjustment is required for elderly patients. ATTRv amyloidosis often presents in the fifth to seventh decade of life, and the clinical trials included patients across a wide age range. No overall differences in safety or efficacy were observed between older and younger patients. However, careful monitoring of vitamin A levels and visual health is particularly important in elderly patients.

Missed Dose

If you miss your scheduled dose of Wainzua, administer the injection as soon as possible. Then continue with your regular monthly injections from that date onward. Do not inject a double dose to make up for a missed injection. If you are unsure about when to take your next dose, contact your doctor, pharmacist, or nurse for guidance.

Overdose

If you inject more Wainzua than you should, contact your doctor immediately or go to the nearest emergency department, even if you do not have any symptoms. Take the medication packaging or the pen with you so that the medical team can identify what was taken. There is no specific antidote for eplontersen overdose. Treatment would be supportive, with monitoring of clinical status and vitamin A levels.

What Are the Side Effects of Wainzua?

Like all medicines, Wainzua can cause side effects, although not everyone who takes it will experience them. The side effects observed during clinical trials are categorized below by their frequency of occurrence. Overall, Wainzua has been shown to have a manageable tolerability profile. The most notable side effect — low vitamin A levels — is an expected pharmacological consequence of reducing TTR (the main vitamin A carrier protein) and is managed with daily vitamin A supplementation.

Clinical trial data from the NEURO-TTRansform study and supporting studies form the basis of the known safety profile of Wainzua. In the pivotal trial, the overall rate of treatment discontinuation due to adverse events was low, indicating that Wainzua is generally well tolerated by patients with ATTRv polyneuropathy.

Low vitamin A levels are the most frequently observed side effect and occur as a direct consequence of Wainzua’s mechanism of action. Because TTR is the primary transport protein for retinol (vitamin A) in the bloodstream, reducing TTR levels inherently reduces the blood’s capacity to carry vitamin A. This is why daily oral vitamin A supplementation is mandatory for all patients receiving Wainzua. Your doctor will monitor your vitamin A levels regularly through blood tests and adjust your supplementation as needed.

Although low vitamin A levels are very common in laboratory measurements, clinically significant vitamin A deficiency with overt symptoms (such as night blindness or severe eye problems) is less frequent when patients adhere to the prescribed supplementation regimen. Nevertheless, any changes in vision or eye symptoms should be reported to your doctor immediately, as early intervention can prevent more serious complications.

Injection site reactions are another category of side effects commonly reported with Wainzua. These include redness (erythema), itching (pruritus), and pain at the injection site. These reactions are generally mild to moderate in intensity and short-lived, typically resolving within a few days without specific treatment. Rotating injection sites between administrations and ensuring the medication has reached room temperature before injection can help minimize these reactions.

Vomiting was reported as a common side effect in clinical trials. It is generally mild and does not typically require discontinuation of treatment. If vomiting is persistent or severe, inform your doctor, who can recommend supportive measures or investigate other potential causes.

Compared to its predecessor inotersen (a first-generation antisense oligonucleotide targeting TTR), eplontersen has demonstrated a notably improved safety profile. Inotersen was associated with risks of thrombocytopenia (low platelet counts) and glomerulonephritis (kidney inflammation) that required regular platelet and renal function monitoring. The GalNAc conjugation technology used in eplontersen allows for more efficient, targeted delivery to liver cells at lower doses, resulting in reduced systemic exposure and fewer off-target effects. In the NEURO-TTRansform trial, the platelet-related and renal safety concerns associated with inotersen were not observed with eplontersen, and routine platelet monitoring is not required for Wainzua.

How Should You Store Wainzua?

Proper storage of Wainzua is essential to maintain the quality, safety, and efficacy of the medication. As a biological product (antisense oligonucleotide), eplontersen is sensitive to temperature extremes and should be handled carefully. Follow these storage guidelines:

• Refrigerated storage: Store Wainzua in the refrigerator at 2–8 °C (36–46 °F). This is the primary storage condition for the pre-filled pens. Keep the pens in the original carton to protect them from light.
• Do not freeze: Freezing can damage the molecular structure of the antisense oligonucleotide and render the medication ineffective. If Wainzua has been accidentally frozen, do not use it.
• Temporary room temperature storage: If needed, Wainzua can be stored outside the refrigerator at a temperature below 30 °C (86 °F) for up to 6 weeks in its original packaging. After 6 weeks at room temperature, the medication must be discarded if not used. This is notably longer than many other injectable biological products, providing practical flexibility for patients who travel or have limited refrigerator access.
• Keep out of reach of children: Store Wainzua in a safe location where children cannot access it.
• Check expiration date: Do not use Wainzua after the expiration date (EXP) printed on the pre-filled pen label and outer carton. The expiration date refers to the last day of that month.
• Inspect before use: Before each injection, visually inspect the solution through the viewing window. The solution should be clear and colorless to yellow. Do not use Wainzua if the solution is cloudy, discolored, or contains visible particles.
• Single use only: Each pre-filled pen is for single use. Do not reuse or share pens between patients.
• Proper disposal: After use, place the pen immediately into an approved sharps disposal container. Do not dispose of pens in household waste. Ask your pharmacist how to properly dispose of used sharps containers.

When traveling with Wainzua, use an insulated bag with a cold pack to maintain the appropriate temperature. The extended room temperature stability of 6 weeks makes Wainzua particularly convenient for travel compared to many other injectable biological medications. Avoid exposing the medication to excessive heat, direct sunlight, or freezing temperatures. When going through airport security, carry the medication in your hand luggage rather than checked baggage to avoid extreme temperatures in the cargo hold.

What Does Wainzua Contain?

Understanding what your medication contains is important, particularly if you have known allergies or sensitivities to specific pharmaceutical ingredients. Below is a detailed breakdown of the composition of Wainzua.

Active Ingredient

The active substance is eplontersen (present as eplontersen sodium), a ligand-conjugated antisense oligonucleotide. Each pre-filled pen contains 45 mg of eplontersen in 0.8 mL of solution. Eplontersen is conjugated to a triantennary N-acetylgalactosamine (GalNAc) moiety that enables targeted delivery to hepatocytes (liver cells) via the asialoglycoprotein receptor.

Inactive Ingredients (Excipients)

Appearance and Packaging

Wainzua is a clear, colorless to yellow solution for injection (injection). It is supplied in a single-use pre-filled pen. Each carton contains one pre-filled pen for single use. The pen is designed for easy self-administration with an integrated needle guard that automatically covers the needle after injection to prevent needlestick injuries.