HSCT & MS: Some Basics and My Thoughts

Hope. When you live with a chronic illness like multiple sclerosis, hope can keep you going. New treatments, especially when they aren’t yet available to a majority of people, always inspire hope. These days, one such treatment that people are hopeful for is HSCT. There are many that are holding onto this hope but don’t fully understand the details of the procedure. I feel like we are often seeing headlines about experiences with HSCT and studies being conducted on HSCT, but we don't have a clear explanation of what it really is. So, I thought I’d try to explain it in a layman's/distilled version that is (hopefully) easy to understand. I also wanted to give my thoughts on the procedure.

What is HSCT?

HSCT stands for Hematopoietic Stem Cell Transplantation. You may also see it referred to as AHSCT where the “A” stands for “autologous,” simply meaning that they are taking the stem cells from you and not using someone else's. The goal of the procedure is to harvest stem cells, which are cells that can reproduce to create more of the same or different specialized cells. Think of them as almost a blank slate that can be guided to create whichever new type of cell is needed.¹ These cells are collected from bone marrow or the blood.

Rebuilding a person's immune system

These cells are then stored while the person’s immune system is essentially erased, at which point the cells are added back with the goal that they rebuild the person’s immune system. A super simplified way of looking at HSCT is that it’s a procedure to recreate a person’s immune system using their own stem cells. As you likely know, with multiple sclerosis, it’s our own immune system that has turned on us, treating the myelin surrounding our nerves as a foreign invader that must be eliminated, just as it would normally do to a virus.

The process of undergoing HSCT for MS

The NMSS has a pretty good overview of HSCT that I will paraphrase here.² These are the kind of details that I think a lot of folks don’t really know. As you will see, it’s far from simple.

• A patient will typically be given around ten days of chemotherapy to stimulate the growth of stem cells after which point they will be harvested and stored.
• After that, the patient is hospitalized and given a powerful mix of chemotherapies for up to eleven days, with the goal being to kill or heavily suppress the immune cells in their body.
• With the immune system eliminated, the patient then has their stem cells reintroduced into their bloodstream.
• The patient is then administered antibiotics and other medications to combat infection because they have no immune system at that point.
• The patient waits, isolated in the hospital at first (typically 2 to 4 weeks) while the immune system slowly rebuilds itself (which often takes between 3 to 6 months but can take longer)

Results of HSCT

If all of that goes well, you have a new immune system that is no longer attacking your own body. That’s pretty amazing, right? To some, it might even sound like the “C” word (Cure! I mean cure). I suppose that depends on your definition of a cure. While this is great at halting disease activity, it does not repair the damage that the disease has already done. It does not do what a true cure would do which is to repair myelin. If you’re in a wheelchair before the procedure, you’ll likely be in one afterward, too. It doesn’t reverse what’s already been done. That’s a pretty important thing to know about this procedure. When HSCT is successful, it essentially has the same result that many experience with the current disease-modifying medications.

Risks of HSCT

While the results can be amazing, it’s important to look at the risks. I think just looking at the steps involved gives you an idea of some of these risks. You are subjecting your body to massive amounts of powerful chemotherapy and antibiotics, as well as enduring a significant amount of time with no immune system, meaning there is no way for your body to fight an infection on its own. That’s extraordinarily dangerous. Some other potential side effects are an increased, long-term risk of developing infections, an increased risk of developing cancer and autoimmune conditions, such as thyroiditis, early menopause, and fertility problems.³

Side effects

The chemotherapy and antibiotics pose their own side effect risks as well - not just hair loss, but fevers, nausea, and even hearing loss. Our own Dave Bexfield, who has survived HSCT, even noted that his consent form listed his chances of dying as 1 in 20. Even if that’s improved since he underwent the procedure in 2010, the chance of death (like the other risks) is not insignificant (those risks are improving, though).⁴ I’m often shocked when people are excited about HSCT but will then balk at the side effects of other disease-modifying treatments. Make no mistake: of the treatments out there, HSCT is the riskiest.

My thoughts about HSCT

People send me success stories and ask me about HSCT all the time and are shocked when I’m quick to dismiss it. Currently, Tysabri has done a pretty good job of slowing down/halting my disease progression (and, if someday it fails, I’d still want to try Ocrevus before HSCT). If I exhausted all other treatments, then sure. I’m just not a good candidate for the procedure because again, it carries a lot of risk for the same result (if it were to work) as my current medication.

HSCT cannot repair the damage that has been done

It’s very important to again note that HSCT cannot regrow myelin. It can not repair the damage that is already done; it is not a cure. That does not negate its potential value, though. For people who are young and have a rapidly progressing course of multiple sclerosis and who have not had luck with any other treatments, it can be, and has been, a lifesaver. It has a very valuable spot on the list of possible MS treatments and has produced some great success stories. It’s just not for everyone. Most people with MS do not make great candidates for the current version of HSCT.

HSCT is still very new

This doesn’t mean that someday, some advanced version of it won’t become the primary way to stop this disease. It (or rather a different version of it) may even have the potential for re-myelination. Doctors are still learning about the process, and it’s being improved. In the grand scheme of things, HSCT is still pretty new; it’s still being studied (just one reason that it’s not yet covered by most insurances).⁵ There is new data coming in from recent studies all the time. I've tried to be cautious with statistics here because of that.

We can be hopeful while being realistic about HSCT

I’ve linked to my sources within this article (and you can also find them in the References section below), but please keep in mind that depending on when you read this, those items could be outdated. That’s just how new and evolving the procedure is. The future is bright for HSCT, but right now, it’s not the best option for most people. That doesn’t mean we can’t still have some excitement and hope for it, but it’s also important to be realistic with regards to our own illness.

Thanks so much for reading and always feel free to share!

Devin

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