Inotersen

Pronunciation: eye-no-terse-in
Generic name: inotersen
Brand name: Tegsedi
Dosage form: prefilled injection for subcutaneous use
Drug class: Miscellaneous metabolic agents

Medically reviewed by Carmen Pope, BPharm. Last updated on Aug 13, 2024.

What is inotersen?

Inotersen (brand name Tegsedi) is a self-administered, once-weekly injection that may be used to treat polyneuropathy caused by hereditary transthyretin-mediated amyloidosis (hATTR) in adults.

Inotersen is an antisense oligonucleotide, a short piece of synthetic RNA that works by attaching to and blocking the mutant gene in people with hATTR responsible for producing abnormal transthyretin (TTR). This mechanism of action of inotersen means it reduces the production of TTR and TTR protein deposits, which eases symptoms of polyneuropathy.

Inotersen gained FDA approval on October 5, 2018, under the brand name Tegsedi. There is no Tegsedi generic available.

Inotersen (Tegsedi) REMS

Because of the risk of serious bleeding kidney problems, inotersen is only available through a restricted program called the Tegsedi Risk Evaluation and Mitigation (REMS) Program.

• Before you begin using inotersen, you must enroll in this program. Talk to your healthcare provider about it.
• You must agree to complete your laboratory testing while in the program.
• You can only get inotersen (Tegsedi) from a certified pharmacy participating in the Tegsedi REMS Program.
• For more information, including a list of certified pharmacies, go to www.tegsedirems.com or call 1-844-483- 4736.

Inotersen side effects

The most common side effects of inotersen are:

• injection site reactions (such as redness or pain at the injection site)
• nausea
• headache
• tiredness
• low platelet counts (thrombocytopenia)
• fever.

Serious side effects and warnings

Inotersen carries a Boxed Warning for low platelet counts (thrombocytopenia) and kidney inflammation (glomerulonephritis).

Low platelet counts (thrombocytopenia) reduce the ability of your body to form clots. You could have serious bleeding that could lead to death. Call your healthcare provider immediately if you have:

• unusual bruising or a rash of tiny reddish-purple spots, often on the lower legs
• bleeding from skin cuts that do not stop or ooze
• bleeding from your gums or nose
• blood in your urine or stools
• bleeding into the whites of your eyes
• sudden severe headaches or neck stiffness
• vomiting or coughing up blood
• abnormal or heavy periods (menstrual bleeding).

Kidney inflammation (glomerulonephritis). Your kidneys may stop working properly resulting in severe kidney damage and kidney failure that needs dialysis. Call your healthcare provider immediately if you have:

• puffiness or swelling in your face, feet, or hands
• new onset or worsening shortness of breath and coughing
• blood in your urine or brown urine
• foamy urine (proteinuria)
• passed less urine than usual.

Your healthcare provider will do laboratory tests to check your platelet count and kidneys before you start inotersen, and while you are using it. Your healthcare provider should also do laboratory tests for 8 weeks after you stop inotersen. You must make sure you get these laboratory tests done.

Inotersen may cause other serious side effects.

Inotersen may cause a stroke. One person had a stroke, which occurred within 2 days after the first dose of inotersen. Get emergency help immediately if you have symptoms of a stroke, which may include:

• sudden numbness or weakness especially on one side of the body
• severe headache or neck pain
• confusion
• problems with vision, speech, or balance
• droopy eyelids.

Serious inflammatory and immune system problems have been reported in people taking inotersen. Talk to your healthcare provider immediately if you have weakness or spasms in your legs, back pain, weight loss, headache, vomiting, or problems with your speech or walking.

Inotersen may cause liver problems. Your healthcare provider should do laboratory tests to check your liver before you start treatment and while you are using it. Tell your healthcare provider if you develop any liver symptoms such as unexpected nausea and vomiting, stomach pain, not feeling hungry, yellowing of the skin, or having dark urine.

Inotersen may cause serious allergic reactions. These allergic reactions often occur within 2 hours of injecting inotersen. Get emergency help immediately if you have any symptoms of an allergic reaction including joint pain, chest pain, high blood pressure, chills, flushing, difficulty swallowing, redness on palms of hands, tremors or jerking movements, muscle pain, or flu-like symptoms.

Eye problems caused by low vitamin A levels may occur because treatment with inotersen will lower the Vitamin A levels in your blood. Your healthcare provider should tell you to take Vitamin A supplements while using inotersen and what dose to take. Call your healthcare provider if you have eye problems, such as having difficulty seeing at night or in low-lit areas (night blindness). Your healthcare provider should send you to see an eye doctor (ophthalmologist).

It is not known if inotersen is safe and effective in children.

These are not all the possible side effects of inotersen. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before taking

You should not receive inotersen if you:

• Have a low platelet count (less than 100 x 10⁹/L )
• Have had kidney inflammation (glomerulonephritis) caused by inotersen (Tegsedi)
• Have had an allergic reaction to inotersen or any of the ingredients in Tegsedi. See the end of this guide for a list of ingredients.

Before you start using inotersen, tell your healthcare provider about all your medical conditions, including if you:

• Have or had bleeding problems
• Have or had kidney problems
• Have received a liver transplant
• Are pregnant or plan to become pregnant
• Are breastfeeding or plan to breastfeed.

Pregnancy

It is not known if inotersen can harm an unborn baby. There is a registry for women who become pregnant during treatment with inotersen if you become pregnant while taking inotersen; talk to your healthcare provider about registering with the TEGSEDI Pregnancy Exposure Registry.

The purpose of this registry is to collect information about your health and your baby’s health. You can get more information about this registry by calling: 1-877-465-7510, emailing: tegsedipregnancy@ubc.com, or visiting online at: www.tegsedipregnancystudy.com.

Breastfeeding

It is not known if inotersen can pass into your breast milk or harm your baby. Talk with your healthcare provider about the best way to feed your baby while you are using it.

How should I use inotersen?

Your healthcare provider will show you or your caregiver how to inject inotersen the first time. Do not attempt to use it until you have been shown how to do so. Also, read the detailed medication guide.

• Inotersen is injected under your skin (subcutaneously) either in your stomach area (abdomen, but not within 2 inches of your belly button) or the front of your upper legs (thighs) by you or a caregiver.
  • A caregiver may also give you an injection in the outer area of your upper arm.
• Do not inject into the same site each time or where the skin is bruised, tender, red, or hard.
• Do not inject into areas with scars or tattoos or through clothing.

Inotersen (Tegsedi) is usually injected once a week. It should be injected on the same day each week (for example, every Monday)

Inotersen dosing

The recommended dosage for adults is inotersen 284 mg (one prefilled injection) once weekly.

• Laboratory tests must be performed before treatment, throughout treatment, and for 8 weeks following discontinuation.

What happens if I miss a dose

If you miss a dose, take the missed inotersen dose as soon as possible, unless your next scheduled dose is within 2 days. If your next scheduled dose is within 2 days, skip the missed dose and take your next scheduled dose on the scheduled day.

What other drugs will affect inotersen?

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Especially tell your healthcare provider if you take:

• vitamin A or beta-carotene supplements. Your healthcare provider should tell you to take vitamin A at the recommended daily allowance. A higher dose than this should not be taken to try and achieve normal serum vitamin A levels in the body because serum vitamin A levels do not reflect total vitamin A levels. High doses of vitamin A are associated with adverse developmental effects in a growing fetus.
• blood thinners (anticoagulants) or medicines that affect blood clotting.

Ask your healthcare provider or pharmacist if you are not sure if you take any of these medicines. Know the medicines you take. Keep a list of them to show your healthcare provider or pharmacist when you get a new medicine.

Storage

Store inotersen (Tegsedi) in the refrigerator between 36°F to 46°F (2°C to 8°C) in the original container. Do not freeze.

Tegsedi prefilled syringes can also be kept at room temperature less than 86°F (30°C) in the original container for up to 6 weeks. Do not exceed these temperatures. If you do not use Tegsedi that has been kept at room temperature within 6 weeks, throw it away.

Protect from light.

Keep out of the reach of children.

Tegsedi ingredients

Active ingredients: inotersen 284 mg/ 1.5 mL

Inactive ingredients: purified water (water for injection), hydrochloric acid, and or sodium hydroxide for pH adjustment.

Available as a single-dose prefilled syringe.

Who makes inotersen?

Sobi Inc. makes inotersen under the brand name Tegsedi.

Frequently asked questions

• Onpattro vs Tegsedi - how do they compare?
• What is the Tegsedi REMS Program?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer