daratumumab (Darzalex)

Darzalex is a prescription medicine used to treat multiple myeloma:

• In combination with the medicines bortezomib, melphalan and prednisone, in people with newly diagnosed with multiple myeloma who cannot receive a type of stem cell transplant that uses their own stem cells (autologous stem cell transplant).
• In combination with the medicines lenalidomide and dexamethasone, or bortezomib and dexamethasone, in people who have received at least one prior medicine to treat multiple myeloma.
• In combination with the medicines pomalidomide and dexamethasone in people who have received at least two prior medicines to treat multiple myeloma, including lenalidomide and a proteasome inhibitor.
• Alone in people who have received at least three prior medicines to treat multiple myeloma, including a proteasome inhibitor and an immunomodulatory agent, or did not respond to a proteasome inhibitor and an immunomodulatory agent.

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

Before you receive Darzalex, tell your healthcare provider about all of your medical conditions, including if you:

• have a history of breathing problems
• have had shingles (herpes zoster)

Darzalex may cause serious reactions, including:

• Infusion reactions. Infusion reactions are common with Darzalex and can be severe. Your healthcare provider may temporarily stop your infusion or completely stop treatment with Darzalex if you have infusion reactions. Get medical help right away if you get any of the following symptoms:
  • shortness of breath or trouble breathing
  • dizziness or lightheadedness (hypotension)
  • cough
  • wheezing
  • throat tightness
  • runny or stuffy nose
  • headache
  • itching
  • nausea
  • vomiting
  • chills
  • fever
• Changes in blood tests. Darzalex can affect the results of blood tests to match your blood type. These changes can last for up to 6 months after your final dose of Darzalex. Your healthcare provider will do blood tests to match your blood type before you start treatment with Darzalex. Tell all of your healthcare providers that you are being treated with Darzalex before receiving blood transfusions.
• Decreases in blood cell counts. Darzalex can decrease white blood cell counts which help fight infections and blood cells called platelets which help to clot blood. Your healthcare provider will check your blood cell counts during treatment with Darzalex. Tell your healthcare provider if you develop fever or have signs of bruising or bleeding.

• tiredness
• nausea
• diarrhea
• shortness of breath
• fever
• cough
• muscle spasms
• back pain
• cold-like symptoms (upper respiratory infection)
• nerve damage causing tingling, numbness or pain
• swollen hands ankles or feet
• constipation
• trouble sleeping
• joint pain
• vomiting
• chills
• dizziness

Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of Darzalex. Call your doctor for medical advice about side effects.

• Darzalex may be given alone or together with other medicines used to treat multiple myeloma.
• Darzalex will be given to you by your healthcare provider by intravenous (IV) infusion into your vein.
• Your healthcare provider will decide the time between doses as well as how many treatments you will receive.
• Your healthcare provider will give you medicines before each dose of Darzalex and after each dose of Darzalex to help reduce the risk of infusion reactions.
• If you miss any appointments, call your healthcare provider as soon as possible to reschedule your appointment.

Interference with Indirect Antiglobulin Tests (Indirect Coombs Test)

Daratumumab binds to CD38 on RBCs and interferes with compatibility testing, including antibody screening and cross matching. Daratumumab interference mitigation methods include treating reagent RBCs with dithiothreitol (DTT) to disrupt daratumumab binding or genotyping. Since the Kell blood group system is also sensitive to DTT treatment, K-negative units should be supplied after ruling out or identifying alloantibodies using DTT-treated RBCs.

If an emergency transfusion is required, non-cross-matched ABO/RhD-compatible RBCs can be given per local blood bank practices.

Interference with Serum Protein Electrophoresis and Immunofixation Tests

Daratumumab may be detected on serum protein electrophoresis (SPE) and immunofixation (IFE) assays used for monitoring disease monoclonal immunoglobulins (M protein). This can lead to false positive SPE and IFE assay results for patients with IgG kappa myeloma protein impacting initial assessment of complete responses by International Myeloma Working Group (IMWG) criteria. In patients with persistent very good partial response, consider other methods to evaluate the depth of response.

• Darzalex may harm your unborn baby.
  • Females who are able to become pregnant should use an effective method of birth control during treatment and for at least 3 months after your final dose of Darzalex. Talk to your healthcare provider about birth control methods that you can use during this time.
• It is not known if Darzalex passes into your breast milk.