Published on September 10, 2015
At a recent multiple myeloma town meeting at MD Anderson Cancer Center in Houston, myeloma expert Dr. Robert Orlowski, responded to an audience member's question about harvesting stem cells before smoldering myeloma becomes active to use for transplant later. Dr. Orlowski expands on this common question and discusses the risks associated with early harvest of stem cells.
Transcript | Smoldering Myeloma: Why Not Harvest Stem Cells Now?
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Dr. Orlowski, a patient online says, “I’m 41. I have asymptomatic myeloma. Why not harvest my stem cells now before I progress to active myeloma rather than my doctor saying I should wait until progression followed by chemo before harvesting?”
Good question. And sometimes, when patients are newly diagnosed even with symptomatic myeloma, they say why shouldn’t I collect my stem cells now before I go to do chemotherapy? And the reason is one of the concerns we have about collecting stem cells when there is myeloma present is that you can get contamination of the stem cell product, which is collected from the patient with a few myeloma cells. That’s why we usually like to do chemotherapy first to kill off as many myeloma cells as possible.
If there is contamination, the risk is that when you then get your stem cells put back in, you’re getting mostly your normal stem cells, but you’re getting a few myeloma cells back as well. And that can contribute to the risk of relapse. So that’s why we only collect stem cells, for the most part, after people have had chemotherapy when, hopefully, their myeloma is at its lowest.
So let me ask a follow-up. If the stem cells are harvested, and there’s a little bit of myeloma in that harvest, do those myeloma cells survive the freezing and thawing that would take place in the stem cell process?
That’s a great question. It is true that the myeloma cells are very fragile. One of the things we do, I have a laboratory, we study myeloma. If we take myeloma cells from a patient that’s had a bone marrow, and we try to grow them in the laboratory, they live maybe three or four days tops no matter how well we feed them.
But there are studies that show that the amount of contamination of the stem cell product is related to the risk of relapse. So some, at least, of these contaminating cells do survive long enough to potentially cause relapse in the future. One of the things that we’re trying to do is do what’s called purging. And that’s to take the stem cell product that’s been collected, treat it with some kind of drug in the laboratory that would specifically kill off the myeloma cells, and then you would have a purer product and use that. So far, the problem has been that the drugs we’ve had have not been able to differentiate between the myeloma cells and the normal cells.
But some of these immune therapies that we talked about earlier, in particular, the antibodies I think are very promising for that. And I think we’re going to be revisiting this purging question in the future.