Darzalex: Uses, Side Effects and Dosage

What Darzalex is used for:

Darzalex is used in adults 18 years or older to treat a type of cancer called multiple myeloma. This is a cancer of your plasma cells which are found in your bone marrow.

How Darzalex works:

Darzalex contains the active substance daratumumab. Daratumumab belongs to a group of medicines called monoclonal antibodies. Daratumumab attaches to myeloma cells and works in multiple ways to kill the cancer cells. You may be prescribed Darzalex with other multiple myeloma medicines, or you may have used other multiple myeloma drugs previously. Darzalex works differently compared to these other medicines.

The ingredients in Darzalex are:

Medicinal ingredients: daratumumab.

Non-medicinal ingredients: L-histidine, L-histidine hydrochloride monohydrate, L-methionine, polysorbate 20, sorbitol, water for injection.

Darzalex comes in the following dosage forms:

Darzalex is provided as a concentrate that must be diluted in a sodium chloride solution and is then administered by intravenous infusion. It comes in vials. Each vial of 5 mL concentrate contains 100 mg of daratumumab (concentration of 20 mg/mL). Each vial of 20 mL concentrate contains 400 mg of daratumumab (concentration of 20 mg/mL).

Do not use Darzalex if:

• you are allergic to daratumumab or any of the other ingredients in Darzalex.

If you are not sure, talk to your doctor or nurse before you are given Darzalex.

To help avoid side effects and ensure proper use, talk to your healthcare professional before you take Darzalex. Talk about any health conditions or problems you may have, including if you:

• are pregnant, think you might be pregnant or are planning to have a baby. If you become pregnant while being treated with Darzalex, tell your doctor or nurse immediately. You and your doctor will decide if the benefit of receiving Darzalex is greater than the risk to your baby. Women who are being treated with Darzalex must use effective contraception during treatment and for at least 3 months after treatment. Darzalex may harm your unborn baby.

• are producing breast milk. You and your doctor will discuss if giving your baby breast-milk may harm your baby. This is because the medicine may pass into the mother’s milk and it is not known if it will affect the baby.
• You must not give your baby breast-milk if you are also taking lenalidomide or thalidomide with Darzalex. Talk to your doctor about risks of any other products before deciding to give your baby breast-milk.

• have breathing problems, such as asthma or Chronic Obstructive Pulmonary Disease (COPD). You will be given medicines to inhale which will help if you have breathing problems after the infusion:

  • medicines to help the airways in your lungs stay open (bronchodilators)
  • medicines to lower swelling and irritation in your lungs (corticosteroids)
• had shingles (herpes zoster).
• had or might now have a hepatitis B virus infection.
• have hereditary fructose intolerance (HFI). Darzalex contains sorbitol. Sorbitol is a source of fructose. People with HFI cannot break down fructose, which may cause serious side effects. Patients with HFI must not be given Darzalex unless necessary.

If you need a blood transfusion, you will have a blood test first to match your blood type. Darzalex can affect the evaluation of the results of this blood test. Tell the person doing the test that you are taking Darzalex.

Other warnings you should know about:

Infusion-related reactions:

Before and after each infusion of Darzalex, you will be given medicines that help to lower the chance of infusion-related reactions. These reactions can happen during the infusion or in the 3 days after the infusion. These reactions are most likely to happen at the first infusion. Some serious allergic reactions and other severe infusion-related reactions have resulted in death.

Tell your doctor or nurse immediately if you get any of the symptoms of an infusion-related reaction. These symptoms include:

• chills
• sore throat/throat tightness
• fever
• cough
• feeling sick
• itchy, runny or blocked nose
• feeling short of breath or other breathing problems including wheezing
• increased blood pressure
• dizziness or light-headedness
• headache
• rash or hives
• nausea
• vomiting
• itchiness

Although rare, you may have a severe allergic reaction. Tell your doctor or nurse immediately if you get any of the symptoms of a severe allergic reaction, which include:

• swollen face, lips, mouth, tongue or throat
• difficulty swallowing or breathing
• an itchy rash (hives)
• chest pain
• eye pain
• blurred vision

If you have an infusion-related reaction, you may need other medicines, or the infusion may need to be slowed down or stopped. When these reactions go away or get better, the infusion can be started again. Your doctor may decide not to use Darzalex if you have a severe infusion-related reaction.

Infections: Darzalex may increase the occurrence of infections. These infections could be severe, life-threatening or potentially fatal. Tell your healthcare professional if you develop fever, feel very tired, have a cough or have flu-like symptoms.

Hepatitis B Virus: Tell your doctor if you have ever had or might now have a hepatitis B virus infection. This is because Darzalex could cause hepatitis B virus to become active again. Your doctor will check you for signs of this infection before, during and for some time after treatment with Darzalex. Tell your doctor right away if you get worsening tiredness or yellowing of your skin or white part of your eyes.

Changes in blood tests: Darzalex can affect the results of blood tests to match your blood type. This interference can last for up to 6 months after your final dose of Darzalex. Your healthcare professional should do blood tests to match your blood type before you start treatment with Darzalex. Tell all of your healthcare professionals that you are being treated with Darzalex before receiving blood transfusions.

Decreased blood cell counts: Darzalex can decrease white blood cell counts which help fight infections, and blood cells called platelets which help to clot blood. Tell your healthcare professional if you develop fever, trouble breathing, cough, burning or pain when you urinate, or any other signs and symptoms of infection, or if you have signs of bruising or bleeding.

Pregnancy: Lenalidomide and thalidomide are expected to be harmful for an unborn baby. When Darzalex is given in combination with lenalidomide or thalidomide, you must also read the patient medication information for that product. When lenalidomide or thalidomide is used, you must follow the pregnancy prevention programme for that product. Other medicines used together with Darzalex may harm an unborn baby. You should also read the patient medication information for these other medications.

Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.

Interactions with other drugs, vitamins, minerals, natural supplements or alternative medicines have not been established with Darzalex.

How to take Darzalex:

• Darzalex will be given to you by a doctor or nurse who will have access to emergency equipment and medical support to manage infusion-related reactions if they occur (see “Other warnings you should know about”).
• It is given over several hours as a drip into a vein (“intravenous infusion”).

Usual dose:

Your doctor will determine your dose of Darzalex. This will depend on your body weight.

The usual starting dose of Darzalex is 16 mg per kilogram of body weight. Darzalex may be given alone or together with other medicines used to treat multiple myeloma.

When given alone or with some medicines (bortezomib, carfilzomib, lenalidomide, dexamethasone, melphalan, or prednisone), Darzalex is given as follows:

• once a week for the first 6, 8 or 9 weeks
• then once every 2 or 3 weeks for 15, 16 or up to 48 weeks
• then once every 4 weeks after that as long as your condition does not worsen

When given as part of induction and consolidation therapy with thalidomide, Darzalex is given as follows:

• once a week for the first 8 weeks
• then once every 2 weeks for 8 weeks
• stop for chemotherapy and autologous stem cell transplant
• then once every 2 weeks for 8 weeks

Depending on which other medicines Darzalex is given together with, your doctor may change the time between doses as well as how many treatments you will receive.

In the first week your doctor may give you the Darzalex dose split over two consecutive days.

Other medicines given during treatment with Darzalex

Before each infusion of Darzalex you will be given other medicines that help to lower the chance of infections, inflammation or allergic reactions. These may include:

• medicines for an allergic reaction (anti-histamines)
• medicines for inflammation (corticosteroids)
• medicines for fever (such as acetaminophen)
• medicines to prevent or treat an infection (anti-microbials)

After each infusion of Darzalex you will be given other medicines (such as corticosteroids) to lower the chance of a reaction after your infusion.

People with breathing problems:

If you have breathing problems, such as asthma or Chronic Obstructive Pulmonary Disease (COPD), you will be given medicines to inhale which help your breathing problems:

• medicines to help the airways in your lungs stay open (bronchodilators)
• medicines to lower swelling and irritation in your lungs (corticosteroids)

You may be given medicines to lower the chance of getting shingles.

Overdose:

This medicine will be given by your doctor or nurse. In the unlikely event that you are given too much (an overdose) your doctor will check you for side effects.

If you think you, or a person you are caring for, have taken too much Darzalex, contact a healthcare professional, hospital emergency department, regional poison control centre or Health Canada’s toll-free number, 1-844 POISON-X (1-844-764-7669) immediately, even if there are no signs or symptoms.

Missed dose:

It is very important to go to all your appointments. If you miss an appointment, tell your doctor and make another one as soon as possible.

Possible side effects from using Darzalex:

Darzalex is generally well-tolerated, however, like all medicines, this medicine can cause side effects.

These are not all the possible side effects you may have when taking Darzalex. If you experience any side effects not listed here, contact your healthcare professional.

Side effects of Darzalex (taken alone or in combination with other drugs) that may affect more than 1 in 5 people (≥20%) include:

• feeling tired
• nausea
• diarrhea
• constipation
• cough
• low number of red blood cells (anemia)
• low number of white blood cells (neutropenia)
• low number of a type of blood cell called platelets (thrombocytopenia)
• fever
• swelling
• infections of the airways – such as nose, sinuses or throat
• peripheral sensory neuropathy (numbness or tingling in feet or hands)
• feeling very weak
• shortness of breath (including due to build-up of fluid in the lungs)

Other side effects affecting more than 1 in 20 people (≥5%) include:

• chills
• muscle spasms
• headache
• dizziness
• fainting
• loss of appetite
• difficulty falling asleep
• vomiting
• stomach ache
• pain in the back, chest, arms, legs, muscles, joints, or bones
• pain in the mouth or throat
• rash or itchy skin
• lung infection (such as pneumonia or bronchitis)
• flu or flu-like illness, stuffy nose
• prickling or burning sensation on the skin (paresthesia)
• trembling or shaking hands (tremor)
• altered taste
• urinary tract infection
• low number of white blood cells (lymphopenia, leukopenia)
• decrease in levels of calcium in your blood
• decrease in levels of potassium in your blood
• increase in blood sugar
• increased (hypertension) or decreased (hypotension) blood pressure
• anxiety or depression
• kidney impairment
• weight decrease

Serious side effects and what to do about them

If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.

Reporting side effects

You can report any suspected side effects associated with the use of health products to Health Canada by:

• Visiting the Web page on Adverse Reaction Reporting (canada.ca/drug-device-reporting) for information on how to report online, by mail or by fax; or
• Calling toll-free at 1-866-234-2345.

NOTE: Contact your healthcare professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice.

Storage:

Darzalex will be stored in a refrigerator at 2-8˚C.

If you want more information about Darzalex:

• Talk to your healthcare professional
• Find the full product monograph that is prepared for healthcare professionals and includes the Patient Medication Information by visiting the Health Canada Drug Product Database website: (Drug Product Database: Access the database); the manufacturer’s website (innovativemedicine.jnj.com/canada), or by calling 1-800-567-3331 or 1-800-387-8781.

Janssen Inc., a Johnson & Johnson company

Toronto, Ontario, M3C 1L9

Date of Authorization: 2026-07-02

All trademarks used under license