Biologically Targeted Therapies for Multiple Myeloma

Researchers are beginning to understand the complex process involved when a healthy cell turns cancerous. This has paved the way for the emergence of better targeted therapies for many forms of cancer, including multiple myeloma. Unlike traditional therapies—such as chemotherapy and radiation, which do not distinguish between fast-growing healthy cells and cancer cells—targeted therapies home in on a specific biologic pathways that enable cancer cells to thrive. They might prevent the cells from creating the new blood vessels they need to grow and spread. Or they might stop certain key proteins from helping the cells to grow.

Three targeted therapies are now being used in the treatment of multiple myeloma:

• Thalomid^® (thalidomide) - This oral medication appears to block some of the ways that myeloma cells grow and thrive. It stops the formation of new blood vessels and proteins called growth factors, which enable the cells to grow. It also may help to stimulate the body’s immune system.
  Thalidomide is often used together with other medications, such as the corticosteroid dexamethasone and/or chemotherapy. Usually, doctors start patients on a lower dose, gradually increasing it over a few weeks. It may take a few months for the medication to take effect. Patients usually stay on the drug as long as it is working and they can tolerate the side effects.
  Thalidomide can cause a potentially serious side effect called deep vein thrombosis, or DVT. This is the formation of a blood clot in the vein. Therefore, doctors may also prescribe a medication that prevents blood clotting, such as Coumadin^® (warfarin) or Lovenox^® (heparin), or recommend taking aspirin.
• Revlimid^® (lenalidomide) - Revlimid is similar to thalidomide, but it appears to be more potent and causes different side effects. Researchers do not yet fully understand how it works. It appears to stop myeloma cells from growing and dividing. It also seems to play a role in keeping the cells from developing the new blood vessels they need to thrive.
  Typically, lenalidomide is used as a second-line therapy for multiple myeloma, usually in combination with dexamethasone. “Second-line” means that it is given after a prior therapy stops working. However, it is now being investigated as a possible first treatment for myeloma.
  Like thalidomide, it is an oral medication, and the dose is usually adjusted based on how the disease responds and whether the patient experiences side effects. It also can increase the risk of blood clots, or DVT. Doctors may prescribe a medication that prevents blood clotting, such as warfarin or heparin, or recommend taking aspirin.
• Velcade® (bortezomib) - Velcade seems to work by interfering with the growth and survival of myeloma cells. It also causes cell death. Often it is used in combination with other treatments. Like lenalidomide, it is typically given after a patient has received at least one prior therapy. However, it is now being investigated as a possible first treatment for myeloma.
  Bortezomib is given intravenously (into a vein) on a monthly cycle. A typical schedule might have a patient receiving the drug twice per week for 2 weeks, followed by a 10-day rest period. However, the schedule can vary from person to person, depending on his or her needs and the side effects that develop.