Polly: Stem cell treatment seems to be available for other illnesses, why is it not for MS?
Professor Gavin Giovannoni, Neurologist: Stem cell treatment. It depends what kind of stem cells you’re talking about. So people’s idea is that stem cells which you give them back and they repair the brain. That to me is science fiction at the moment, we’ve got no evidence that stem cells go into the brain and repair the brain. The stem cell therapies that are being tested at the moment are these ones derived from the skin or the bone marrow, we call these mesenchymal, they come from a type of tissue. And these, when given intravenously in a drip, seem to modulate the immune system, they act as immune modulators, and that’s what’s being tested right now in clinical trials. None of those trials have been large enough and extensive enough to become convincing that the strategy works. So it’s not a case of we’re not giving them, it’s that the process of developing stem cell therapies is still in its infancy and we’re having to develop them by clinical trials. Whereas in other conditions, like cancers, for example, various inborn errors, these are genetic diseases, we now have evidence that by replacing the bone marrow or giving stem cells from the bone marrow can cure the disease. That’s a completely different field. So it’s not that we don’t have stem cell therapies, it’s that we need to test them properly.
Polly: Okay, are you hopeful that they’ll come along in the next few years and they’ll become sort of a frontline thing, or do you think there’s other things that…
Professor Gavin Giovannoni: Well, I mean it depends how effective they are, because you may find that the stem cell therapies work, but they don’t work as well as the drugs we have available at the moment. And the process of doing stem cells is not trivial; it’s quite an expensive and high risk procedure. So it all depends on risks and benefits again and how those risks and benefits stack up against the current therapies that we have. But I think one of the problems the field has faced is that people have got this idea that stem cell therapies, they’ve been designed to repair damaged spinal cords and brains, and that’s not… the data for that is very poor and I don’t think the community should be expecting that to happen in the next five to ten years, that’s really a ten, 20, 30 year timeframe for repair.
I remember hearing an Italian guy talking about taking, sort of depleting the immune system and then once it’s sort of at near enough nothing, re-putting it back.So that’s, I mean in the past that was called bone marrow transplantation, so what we used to have to do then is actually suck out the stem cells from the bone marrow. Nowadays we have a way of mobilising those stem cells and we take them from the peripheral blood. That’s called Hematopoietic – in your blood, okay – Stem Cell Therapy, HSCT. And that’s essentially, what we do is we actually mobilise the stem cells. What we do is give a small dose of chemotherapy with a growth factor that stimulates the bone marrow. The bone marrow then releases the stem cells into the blood, we take a blood transfusion essentially, and we separate out those stem cells, freeze them away, and then we take that individual and we give them high dose chemotherapy to ablate the immune systems, to destroy the immune systems. We then give them back their own stem cells that we’ve put in the freezer and then that repopulates the immune system. And that’s what I would call like an aggressive rebooting.
Now, there’s different aggressions. There are people that do – myeloablative means you ablate the immune system completely – and then there are some people who do a partial myeloablative, or non-myeloablative, you don’t give aggressive therapy, but just a little bit to suppress it slightly and you repopulate. The idea then is by killing off the autoimmune cells and giving back a new immune system, you get rid of MS. And there are trials going on for that, several trials in various different countries: Canada, United States, Europe are doing trials. So we have to wait for the results to come in. There have been some preliminary results that look very, very interesting, which is why people are very excited by this. But again, the stem cell therapy protocol is very risky. There’s a high risk of getting infections and complications from the procedure and the mortality, that’s the risk of dying from the procedure, is between – depending where you have it – between 0.5 and 2%. In the previous, in the past, it was even higher than that, so the modifications of the procedure have lowered the risk, but you’ve got to be prepared to die from that procedure. So that’s why it’s high risk.
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Professor Gavin Giovannoni has an MBBCh, PhD, FCP (Neurol., SA), FRCP, FRCPath amongst his qualifications. He is the Chair of Neurology at Barts and The London School of Medicine. His research interests have focused around multiple sclerosis and inflammatory disorders of the central nervous system. His teaching focuses on clinical neurology and neuroimmunology.