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How long does Darzalex work?

Medically reviewed by Carmen Fookes, BPharm. Last updated on May 20, 2020.

Official Answer

by Drugs.com
  • Darzalex is administered until signs of progression of multiple myeloma (MM) occur, or side effects become intolerable.
  • Treatment durations of up to 25 months have been reported in clinical trials (range 0.1 month to 40.44 months).
  • Research suggests people with IgG MM may be more responsive to Darzalex treatment.
  • In clinical trials, it took approximately one month for Darzalex to start working.

Darzalex (daratumumab) is a targeted monoclonal antibody that may be used to treat adult patients with multiple myeloma (bone marrow cancer).

Darzalex works by blocking a certain protein on stem cells causing cell death and reducing the numbers of other cells. It also helps your immune system identify and destroy multiple myeloma cells.

Darzalex is usually given after other treatments have failed and is often given in combination with other treatments.

How long does Darzalex work?

Malignant cells of people with multiple myeloma can also produce large amounts of antibodies (these are known as the myeloma protein, or M-protein, including IgG).

This excess IgG antibody can interfere with the clearance Darzalex as well as levels of exposure to the drug.

Research that has compared the differences in the effect of Darzalex in multiple myeloma patients whose MM cells produce IgG antibody compared with those who produce non-IgG antibody found:

  • In those with IgG myeloma, Darzalex clearance was 110 percent higher compared to non-IgG myeloma patients
  • The predicted trough serum concentrations in non-IgG myeloma patients were approximately 70 percent higher than those of IgG myeloma patients on the first day of the third cycle of Darzalex administration
  • This means that the amount of drug left in circulation is higher in non-IgG MM patients and that the drug is cleared from circulation faster in IgG MM patients.

Further analysis showed Darzalex was almost two times more effective in myeloma patients producing IgG antibodies compared to non-IgG MM patients, suggesting that patients with IgG myeloma may be more responsive to this treatment.

Reports of side effects were similar between the two groups.

Darzalex is often given with other medications to treat multiple myeloma, and the duration of treatment can depend on the tolerability of the whole regimen, not just Darzalex.

Clinical trials have reported treatment durations of up to 25.3 months (range 0.1 month to 40.44 months).

How is Darzalex given?

Darzalex is administered by infusion directly into a vein. Other medications, such as corticosteroids, antipyretics, and antihistamines are given before and after the infusion to help prevent serious side effects or an allergic reaction.

Darzalex is usually given at a dosage of 16mg/kg actual body weight. The first infusion needs to be given slowly (over approximately 7 to 8 hours) because there is a risk of allergic reactions associated with Darzalex. The risk of reactions decreases with subsequent infusions which can be given over about 4 hours for the second infusion and 3 hours for the following infusions.

Darzalex is usually given every one to three weeks for the first few weeks of treatment, depending on what other treatments you have received for multiple myeloma. Then the frequency of infusions is reduced to once every four weeks until your body no longer responds to Darzalex (indicated by the progression of multiple myeloma).

The effects of Darzalex on blood-typing tests may last for up to 6 months after stopping this treatment.

How does Darzalex work?

A protein called CD38 exists on the surface of hematopoietic cells – these are the stem cells that give rise to other blood cells. CD38 has multiple functions, such as cell binding (including during inflammation), cell signaling, and regulating enzyme activity.

Darzalex binds strongly and specifically to CD38, and once bound induces an immune response that results in the death of myeloid cancer cells Darzalex also reduces the numbers of myeloid-derived suppressor cells – these are immune cells that originate from bone marrow stem cells whose numbers are significantly increased during chronic infections and cancer, as a result of hematopoiesis (the formation of a range of different blood cells from bone marrow stem cells).

Antibodies are proteins that are used by the immune system to protect our body against foreign invaders, such as bacteria and viruses. They can be classified into five main subtypes IgA, IgD, IgE, IgG, and IgM based on the sequence and structure.

Darzalex is an IgG monoclonal antibody.

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