Darzalex: 7 things you should know

Medically reviewed by Carmen Pope, BPharm. Last updated on Oct 5, 2023.

1. How it works

• Darzalex is a brand (trade) name for daratumumab injection which may be used to treat adults with multiple myeloma who meet certain criteria. It is usually used in combination with other medications but may be used alone. Darzalex is also available in combination with hyaluronidase, as a subcutaneous injection, called Darzalex Faspro.
• Darzalex works by targeting a specific transmembrane protein, called CD38, that exists on the surface of hematopoietic cells (an immature cell that can develop into all types of blood cells, including white blood cells, red blood cells, and platelets), including multiple myeloma and other cell types and tissues. CD38 has multiple functions, such as adhesion, signaling, and modulation of enzyme activity. When Darzalex binds to this protein, it causes CD38-expressing tumor cells to self-destruct or disintegrate.
• Darzalex belongs to the class of medicines called CD38 monoclonal antibodies. It may also be called a targeted treatment, a biologic, or a monoclonal antibody.

2. Upsides

• Darzalex may be used in combination with other treatments to treat adults with multiple myeloma (MM) who are newly diagnosed and can or cannot have an autologous stem cell transplant; and in those with MM (including relapsed or refractory MM) who have received at least one prior therapy.
• It can be used as single therapy in adults with MM who have received at least three prior medical treatments including a proteasome inhibitor (PI) and an immunomodulatory agent that they have not responded to.
• Available in two strengths: 100 mg/5 mL (20 mg/mL) and 400 mg/20 mL (20 mg/mL) in single-dose vials.
• Darzalex is not chemotherapy, it is a targeted treatment that works by binding to a protein called CD38 that is present on the surface of hematopoietic cells, including MM cells. When Darzalex binds to this protein, it causes cells that carry this protein to self-destruct or disintegrate.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Upper respiratory tract infections, neutropenia (low neutrophils), infusion-related reactions, thrombocytopenia (low platelets), diarrhea, constipation, anemia (low red blood cells), neuropathy (damage to the nerves in the hands and feet), fatigue, swelling in the ankles, nausea, cough, fever, shortness of breath, and weakness or lack of energy.
• Should not be used in people with a history of severe allergic reactions to daratumumab or any of the components of the formulation. Post-marketing side effects that have been reported include pancreatitis, and cytomegalovirus and listeriosis infections.
• Infusion-related reactions can be fatal. These usually occur during the first infusion (37% of patients), 2% with the week 2 infusion, and cumulatively, 6% with subsequent infusions. The time to onset was 1.5 hours (range immediately to 73 hours). Symptoms include bronchospasm, edema, low blood pressure, angioedema, hypoxia, and ocular adverse reactions including acute myopia and glaucoma. Initial symptoms include respiratory symptoms, nasal congestion, cough, and throat irritation as well as chills, vomiting, and nausea. The infusion should be interrupted for infusion-related reactions of any severity and permanently discontinued if an anaphylactic or life-threatening reaction occurs.
• Darzalex may interfere with cross-matching and red blood cell antibody screening. Always type and screen before starting treatment and blood banks should be told the patient has received Darzalex.
• Complete blood counts require monitoring periodically throughout treatment. Patients with neutropenia should be monitored for signs of infection. The next dose of Darzalex may need to be delayed to allow neutrophil or platelet recovery.
• There is a potential for immunogenicity and the development of treatment-emergent anti-daratumumab antibodies.
• Must be administered via an intravenous infusion by a healthcare professional with facilities to manage severe infusion-related reactions. Cannot be administered via an IV push or bolus. The usual starting rate is 50 mL/hour which may be increased depending on how well tolerated the infusion is.
• Patients need to be premedicated 1 to 3 hours before every Darzalex infusion with a long or intermediate-acting corticosteroid (such as methylprednisolone 100mg IV for the initial infusion; methylprednisolone 60mg oral/IV may be considered for subsequent infusions), oral acetaminophen 650mg to 1000mg, and an antihistamine (such as diphenhydramine 25mg to 50mg oral/IV) to reduce the risk of infusion-related reactions.
• After the infusion, an oral intermediate- or long-acting corticosteroid (such as methylprednisolone 20mg) should be administered for 2 days starting the day after the Darzalex infusion. Patients with a history of COPD may require long-acting bronchodilators and inhaled corticosteroids. Antiviral prophylaxis to prevent herpes zoster reactivation should be started 1 week after the Darzalex infusion and continued for 3 months following the end of treatment.
• Darzalex can cause fetal harm if administered to pregnant women, including depletion of fetal immune cells and decreased bone density. Those of childbearing potential should use effective contraception while receiving Darzalex and for 3 months after the last dose. If a woman becomes inadvertently pregnant she should advise her doctor immediately. Women should not breastfeed during treatment with Darzalex.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

• Darzalex is a CD38 monoclonal antibody that may be used to treat Multiple Myeloma, usually in combination with other treatments. It is given by infusion and upper respiratory tract infections, neutropenia (low neutrophils), and infusion-related reactions are the most common side effects. Patients need to be premedicated 1 to 3 hours before every Darzalex infusion with a corticosteroid, acetaminophen, and an antihistamine. Darzalex is also available in combination with hyaluronidase, as a subcutaneous injection, called Darzalex Faspro.

5. Tips

• Before starting treatment with Darzalex, and during treatment with Darzalex, tell your health care provider if you think you have an infection or have symptoms of an infection such as a fever, chills, muscle aches, cough, shortness of breath, runny nose, sore throat, red or painful skin or sores on your body, tiredness, or pain during urination. Also, let them know if you have infections that keep coming back.
• Some vaccinations may need to be avoided during treatment with Darzalex and for a few months after stopping it. Take care to avoid people who are unwell and protect yourself from injury.
• Your first infusion of Darzalex will be given slowly to see how well you tolerate it. Your actual appointment time will be longer because premedication with a corticosteroid, acetaminophen, and an antihistamine needs to be administered 1 to 3 hours before giving Darzalex, to lessen the risk of an infusion reaction happening.
• Infusion reactions, some serious, may occur while you are having a Darzalex infusion. Symptoms may include itchy skin, a rash, hives, skin redness, bronchospasm, throat irritation, oropharyngeal pain, shortness of breath, throat edema, flushing, low blood pressure, fever, fatigue, headache, dizziness, nausea, a fast heartbeat, and anaphylaxis.
• Tell your doctor if you are pregnant, intending to become pregnant, or breastfeeding before being administered Darzalex as it is not suitable during pregnancy and breastfeeding. Use effective contraception while receiving Darzalex and for 3 months after the last infusion. If you inadvertently become pregnant, see your doctor immediately.

6. Response and effectiveness

• A 44% reduction in the risk of disease progression or death was reported when Darzalex was used in combination with lenalidomide and low-dose dexamethasone in 737 patients with newly diagnosed MM ineligible for autologous stem cell transplant. The median time to respond was 1.05 months.
• A 50% reduction in the risk of disease progression or death was reported in patients receiving Darzalex in combination with bortezomib, melphalan, and prednisone. After a median follow-up of 40 months, the progression-free survival in the Darzalex arm was 36.4 months compared to 19.3 months in the control arm.
• Similar efficacy results were seen with other treatments in Multiple Myeloma populations. Refer to the prescribing information for the full details.

7. Interactions

Medicines that interact with Darzalex may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with Darzalex. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with Darzalex include:

• antineoplastics, such as capecitabine or cyclophosphamide
• antipsychotics, such as clozapine
• biologics, such as adalimumab, etanercept, golimumab, or infliximab
• fingolimod or golimumab
• HIV medications, such as zidovudine
• immunosuppressants such as azathioprine, cyclosporine, or tacrolimus
• interferon
• live vaccines and some other vaccines, such as BCG, cholera, Covid-19 vaccines, measles, hepatitis b vaccines, yellow fever, or live influenza vaccines (Darzalex may reduce the immune response to vaccination)
• probiotics, such as bifidobacterium or lactobacillus.

Darzalex interferes with antibody screening and cross-matching tests because it binds to CD38 on RBCs. Perform type and matching tests before treatment. Darzalex may also be detected on serum protein electrophoresis and immunofixation assays used for monitoring disease monoclonal immunoglobulins (M protein).

Darzalex may have additive immune-suppressing effects when given with any other medications such as anticancer drugs, immune-modulating, or immunosuppressive therapies, which may increase a person's risk for infection. Take this into account when switching from drugs with prolonged immune effects.

Note that this list is not all-inclusive and includes only common medications that may interact with Darzalex. You should refer to the prescribing information for Darzalex for a complete list of interactions.

References

• Darzalex (daratumumab). Product Information. Updated 01/2023. Janssen Biotech, Inc. https://www.drugs.com/pro/darzalex.html

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Darzalex only for the indication prescribed.

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

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