The number of stem cells harvested from multiple myeloma patients during the first day of collection predicts the success of the entire collection procedure, according to a recent study. Those patients with higher stem cell counts on the first day of collection are more likely to collect enough stem cells for transplantation.
The authors of the study suggested that patients with very low counts of blood forming stem cells on day one of collection should be treated with Mozobil (plerixafor), a drug used to mobilize stem cells from the bone marrow into the blood stream where they can be collected, or undergo collection using a process known as large-volume apheresis.
“In taking care of transplant patients, I know that the period of stem cell mobilization and collection can be very challenging,” said Dr. Hien Duong, lead investigator of the study. “If we can find ways to improve upon this and intervene when needed in order to ensure that enough stem cells can be collected, this can significantly help our patients.”
Despite the use of stem cell mobilization therapy, up to half of all patients fail their first attempt to collect enough stem cells for transplantation. Collection failure may be due to a number of factors, including extensive bone marrow involvement in the cancer, older age, and prior radiation, chemotherapy, or Revlimid (lenalidomide) therapy.
The ability to predict early in the collection procedure which patients will fail to collect enough stem cells for transplantation would prevent further futile collections. Furthermore, it would allow physicians the opportunity to modify treatment prior to future collection procedures to improve stem cell yield.
The purpose of this study, conducted at the Cleveland Clinic Foundation in Ohio, was to determine whether the number of stem cells collected during the first day of collection could predict the success of collecting enough stem cells within five days of collection.
Researchers analyzed the medical records of 172 multiple myeloma patients who had undergone mobilization treatment and stem cell collection procedures between 2001 and 2008.
Of the patients included in the study, 13 percent failed to achieve adequate stem cell counts after five days of collection.
The researchers determined that patients who did not collect more than 0.7 million stem cells/kg on their first day of collection were unlikely to successfully collect enough stem cells during five days of collection.
Among the patients who failed to collect enough stem cells throughout the entire collection process, all but one collected less than 0.7 million stem cells/kg on the first day.
The median five-day total number of stem cells collected from patients achieving 0.7 million stem cells/kg or fewer on the first day was one-fifth the median total number of stem cells collected by those achieving greater than 0.7 million cells/kg on the first day of collection.
The researchers observed collection failure in three-quarters of patients who did not collect more than 0.7 million stem cells/kg on the first day or 1.54 million/kg by the end of the second day.
Researchers confirmed that older age and prior Revlimid treatment were associated with lower stem cell collection numbers.
Of the patients who failed to reach adequate stem cell numbers after five days of collection, 61 percent eventually achieved numbers that allowed them to proceed to transplantation. To collect enough stem cells, 21 percent went beyond five days of collection and 79 percent underwent a second mobilization regimen.
The investigators believe that the identification of patients who are likely to fail to collect adequate stem cell counts for transplantation can be achieved with this prediction method, which they describe as “simple and practical.” Furthermore, they suggest that this individualized approach can be cost-effective and efficient.
According to Dr. Duong, the Cleveland Clinic Foundation is now conducting a study to determine whether patients previously treated with Revlimid are more likely to collect enough stem cells if they are treated with growth factor alone or in combination with Mozobil.
For more information, see the study in the Journal of Clinical Apheresis (abstract).