The International Myeloma Working Group (IMWG) recommends that multiple myeloma patients should have their stem cells collected within four cycles of therapy with Revlimid ^[1] (lenalidomide), thalidomide ^[2] (Thalomid), or Velcade ^[3] (bortezomib). Otherwise, these drugs may interfere with stem cell collection. The recommendations were published in the journal Blood in August.

During an autologous stem cell transplant, physicians collect a patient’s stem cells in the early stages of the patient's anti-myeloma drug regimen, and return these same cells to the individual after the regimen is complete. Transplantation is a common treatment usually given to any multiple myeloma patients who can tolerate it.

Currently, doctors collect stem cells from multiple myeloma patients after about four cycles of an initial drug regimen using some combination of dexamethasone ^[4] (Decadron), Revlimid, thalidomide, and Velcade.

The transplantation of bone marrow cells as a myeloma treatment was first studied in 1957, according to the American Society of Hematology ^[5]’s 50th anniversary review.  Usage of stem cell transplants picked up throughout the 1980s.

Meanwhile, some of the drugs most familiar to people with multiple myeloma today were approved within the last 15 years. Velcade was first synthesized in 1995; a landmark study helped establish thalidomide as a multiple myeloma drug in 1999; and Revlimid was approved by the United States Food and Drug Administration in 2006.

The long gap between when stem cell transplants came into use and when the latest multiple myeloma drugs hit the market means that people with multiple myeloma are treated significantly different now compared to when autologous stem cell transplants were first used. The advances in myeloma treatment have created debate about how stem cell transplants and the new drugs should be used together.

Some researchers argue that the new drugs are so effective that people do not need to have stem cell transplants at all. The IMWG article, on the other hand, says that there is not enough long-term data about survival of people who are treated with these drugs without transplants to make that judgment.

Others worry that the new drugs make stem cells difficult to collect for autologous transplants. To respond to these concerns, 25 IMWG physicians and scientists reviewed published studies on the drugs’ effects on stem cell transplants. They found that:

• Revlimid can interfere with collecting enough stem cells for a transplant. Two studies, published in the journals Leukemia ^[6] and Biology of Blood and Marrow Transplantation ^[7], found that use of Revlimid was the most important factor in doctors’ ability to collect enough stem cells.
• Thalidomide has little to no negative effects on stem cell transplants.
• The results from studies on Velcade’s effects on stem cell collection are mixed.

Since Revlimid can decrease the number of stem cells collected, the IMWG recommends doctors co-administer granulocyte colony-stimulating factor, a medicine that increases the number of white blood cells the body makes.

Scientists do not know exactly how Revlimid decreases the number of stem cells collected from patients. Therefore, the IMWG researchers wrote that “every effort should be made to enroll these patients in clinical trials evaluating these questions.”

For more information on the new IMWG recommendations, please see the article in the journal Blood ^[8].