Italian researchers recently found that most myeloma patients are able to collect sufficient stem cells after a short course of induction therapy with Revlimid, allowing them to undergo two consecutive stem cell transplants.

“Revlimid can be used safely before stem cell mobilization, provided that we use only four courses before mobilization and cyclophosphamide is used to mobilize,” said Dr. Antonio Palumbo, lead author of the study and a researcher at the University of Torino in Italy.

The current standard treatment for younger patients with newly diagnosed myeloma includes induction therapy with at least one novel agent, followed by high-dose chemotherapy and autologous stem cell transplantation. Prior to undergoing high-dose chemotherapy, the patient’s stem cells are collected from their blood. The patient receives the harvested stem cells after chemotherapy to replace any cells that were damaged during treatment.

Stem cell collection remains a key factor for a successful transplant. In order for transplantation to be a viable treatment option, at least two million stem cells per kilogram of body weight must be collected. For patients seeking to undergo two consecutive transplants, a procedure commonly known as tandem or double transplantation, at least four million stem cells per kilogram of body weight must be collected.

Recent research has shown that long-term exposure to novel agents, such as thalidomide ^[1] (Thalomid) or Revlimid ^[2] (lenalidomide), may result in lower stem cell collection compared to patients who were not treated with these agents. In particular, several research groups have demonstrated that thalidomide treatment prior to stem cell collection decreases the yield by 10 percent to 25 percent compared to control groups. According to Dr. Palumbo, induction therapy with Velcade ^[3] (bortezomib) does not affect the amount of stem cells collected.

In the present study, the researchers evaluated the impact of Revlimid exposure on a patient’s ability to successfully harvest stem cells for transplantation. They assigned 346 newly diagnosed myeloma patients with a median age of 57 years to receive induction therapy that included four 28-day cycles of Revlimid plus dexamethasone ^[4] (Decadron).

To improve stem cell mobilization, patients received cyclophosphamide ^[5] and granulocyte-colony stimulating factor (G-CSF) at a median of 37 days following completion of the last induction cycle.

Twenty-one percent of patients required a second course of these stem-cell mobilizing agents because they failed to collect the target collection number of four million stem cells per kg.

After the second course of mobilization treatment, 91 percent of patients successfully collected sufficient stem cells to undergo two consecutive stem cell transplants.  Eight percent of patients did not collect enough stem cells for a single transplant. The median number of collected stem cells was 8.7 million per kg.

Based on these results, Dr. Palumbo advised that newly diagnosed myeloma patients who are contemplating Revlimid induction therapy prior to transplantation use only four courses of treatment, followed by cyclophosphamide and G-CSF to mobilize stem cell collection. If this regimen does not yield sufficient stem cells for transplantation, he suggested that stem cell mobilization should be repeated with Mozobil ^[6] (plerixafor), a drug that increases the movement of stem cells from the bone marrow into the bloodstream for collection.

For more information, please see the article in Leukemia ^[7] (abstract).