Dawnzera

Dawnzera (donidalorsen) is a prescription injection used to prevent attacks of hereditary angioedema in adult and pediatric patients 12 years of age and older. It helps reduce the risk of hereditary angioedema (HAE) symptoms including sudden, unpredictable episodes of severe swelling in the limbs, face, abdomen, and throat, which may be life-threatening. It is not used to treat an HAE attack that has already started.

Dawnzera injection can be self-administered at home once every 4 to 8 weeks using an autoinjector once you have been trained, or can be administered by a caregiver.

Dawnzera FDA approval was granted on August 21, 2025, to Ionis after positive results from the Phase 3 OASIS-HAE study (NCT05139810).

Hereditary angioedema (HAE) is caused by a genetic problem that lets the body make too much bradykinin, a substance that makes blood vessels leak fluid into nearby tissue. That leaking fluid is the swelling of an HAE attack.

Dawnzera is an RNA-targeted medicine that works by reducing the production of prekallikrein (PKK) which reduces excess bradykinin, that helps to prevent hereditary angioedema attacks. Dawnzera's mechanism of action is as a prekallikrein-directed antisense oligonucleotide.

Patients on Dawnzera every 4 weeks had 81% fewer HAE attacks than those who received placebo. Patients on Dawnzera every 8 weeks had 55% fewer HAE attacks.

Dawnzera was studied in the OASIS-HAE clinical trial (NCT05139810), a 24-week trial of 90 adults and children 12 years and older with type I or type II HAE. To be included in the trial, patients had to have had at least 2 attacks during an 8-week run-in period. The trial compared people receiving Dawnzera 80 mg every 4 weeks, Dawnzera 80 mg every 8 weeks, or placebo (a dummy injection).

From week 4 to week 24, the trial also demonstrated people using Dawnzera every 4 weeks also had:

• 89% fewer moderate or severe attacks than placebo
• 92% fewer attacks that needed on-demand treatment than placebo (67% fewer with the every-8-week dose)

The OASIS-HAE results were published in The New England Journal of Medicine as "Efficacy and Safety of Donidalorsen for Hereditary Angioedema."

Serious allergic reactions

Dawnzera can cause serious allergic reactions, including anaphylaxis. Stop using Dawnzera and call your healthcare provider or go to the nearest emergency room right away if you have symptoms of a serious allergic reaction, such as:

• rash
• itching
• trouble breathing
• chest pain
• swelling of your face, lips or tongue
• fainting, dizziness or feeling lightheaded (low blood pressure)

Tell your healthcare provider about all of your medical conditions, including if you:

• have liver problems. Dawnzera is not recommended for people with moderate or severe liver problems.
• have kidney problems. Dawnzera has not been studied in people with moderate or severe kidney problems or end-stage kidney disease.

It is not known if Dawnzera is safe and effective in children younger than 12 years of age.

Do not use this medicine if you have had a serious allergic reaction, including anaphylaxis, to the active ingredient donidalorsen or any of the inactive ingredients in this medicine.

Pregnancy

Pregnant or plan to become pregnant, as it is not known if this medicine can harm your unborn baby. Tell your healthcare provider if you become pregnant during treatment with this medicine.

Breastfeeding

Breastfeeding or plan to breastfeed, as it is not known if Dawnzera passes into your breast milk. Talk to your healthcare provider about the best way to feed your baby while using this medicine.

Common Dawnzera side effects

The most common side effects of Dawnzera are:

• injection site reactions, such as redness, discoloration, pain, itching, hardness, bruising or swelling where the injection was given
• upper respiratory tract infection (such as a cold)
• urinary tract infection
• stomach (abdominal) discomfort

In the clinical trial, all injection site reactions were mild, and most went away without treatment.

Changes in blood test results

• Lower platelet count. Platelets help your blood clot. In the clinical trial, platelet counts fell by an average of 9.6% with the every-4-week dose and 7.9% with the every-8-week dose by week 25, compared with 1.4% with placebo. No one treated with Dawnzera had a platelet count below 50,000/mm3, and there were no major bleeding events linked to a low platelet count.
• Higher liver enzymes. Some people had increases in liver enzyme levels (ALT, AST and GGT). These were generally less than 3 times the upper limit of normal and leveled off.

Serious Dawnzera side effects

Dawnzera can cause serious allergic reactions. See Warnings above for symptoms and what to do.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

• Dawnzera can be self-administered as an injection under your skin (subcutaneous) in your stomach area (abdomen) or the front of your upper legs (thighs). Only a healthcare provider or caregiver may give you an injection in the back of your upper arm.
• Dawnzera is given one time every 4 weeks or one time every 8 weeks, depending on your prescribed dosing frequency.
• Use this injection exactly as your healthcare provider tells you to take it.
• Read the detailed Instructions for Use that comes with your single-dose autoinjector.
• Your healthcare provider will show you and your caregiver how to inject Dawnzera the first time.

The recommended dosage of Dawnzera is 80 mg administered subcutaneously every 4 weeks.

A dosage of 80 mg administered subcutaneously every 8 weeks may be considered.

If you have missed a dose of your injection, administer the missed dose as soon as possible. Then inject this medicine on the regular dosing schedule from the date of the most recently injected dose.

Preparing for injection

Step 1. Prepare the autoinjector

• Take the autoinjector out of the refrigerator 30 minutes before your injection.
• Keep it in the original carton while it warms to room temperature.
• Do not use other heat sources (microwave, hot water, etc.) to warm it up.

Step 2. Check the medicine

• Look at the expiration date and do not use if expired.
• Check the medicine through the viewing window:
• Do not use the autoinjector if:

Step 3. Choose your injection site

• Inject into the stomach (at least 2 inches away from the belly button) or the front of the thigh.
• A caregiver or healthcare provider may inject into the back of the upper arm.
• Do not inject into skin that is bruised, red, hard, scarred, or damaged.

Step 4. Wash and clean

• Wash your hands with soap and water.
• Clean the injection site with an alcohol wipe (circular motion).
• Let the skin air dry. Do not touch the area again before injecting.

Injecting Dawnzera

Step 1. Remove the clear cap

• Hold the autoinjector in the middle, with the clear cap pointing away.
• Pull the clear cap straight off (do not twist).
• Throw it away in the trash or sharps container.
• Do not recap and do not press the orange needle shield with your hands.
• Only remove the cap right before injection.

Step 2. Give the injection

1. Hold the autoinjector in one hand and place the orange needle shield flat against your skin at a 90° angle.2. Push firmly until you hear a click (injection starts). You may hear a second click — this is normal.3. Hold the device in place for 10 seconds to ensure the full dose is delivered. Do not move, twist, or tilt the autoinjector during the injection.

Step 3. Finish and dispose of autoinjector

• Check the viewing window: the orange plunger rod should fill the window.
• Lift the autoinjector straight up. The needle shield will lock in place automatically.
• A small amount of blood or fluid at the site is normal. Apply a cotton ball or gauze, then cover with a small bandage if needed.
• The autoinjector contains one single dose. Do not reuse. Dispose of it in a sharps container.

Always follow your healthcare provider’s instructions. If something doesn’t look right or you have concerns, contact them before using Dawnzera.

For more detailed instructions, see the Package Insert.

Other drugs may interact with this medicine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

• Store in the refrigerator between 36°F to 46°F (2°C to 8°C) in the original carton.
• This injection may be stored at room temperature up to 86°F (30°C) in the original carton for up to 6 weeks. If not used within 6 weeks, throw away injection..
• Do not freeze.
• Do not expose the autoinjector to heat.
• Protect from direct light.

Keep all medicines out of the reach of children.

Active ingredient: donidalorsen

Inactive ingredients: disodium hydrogen phosphate; sodium chloride; sodium dihydrogen phosphate; water for injection; and may include hydrochloric acid or sodium hydroxide. Phosphorous and sodium.

Dawnzera Ionis Pharmaceuticals Inc.