After many years of exploration and mixed results, there have been recent positive steps forward for people with MS considering autologous haemopoietic stem cell transplant (AHSCT). As an invasive treatment with significant concerns and potential side effects, AHSCT isn’t for the faint-hearted, and not something to consider for most people with MS. However, the evidence is mounting that there’s a very distinct group of people with MS, for whom AHSCT is more likely to work well.
What is AHSCT?
Like the chemotherapy treatment used to treat blood cancers, AHSCT is used to kill off the immune cells in the body before reintroducing the patient’s own (autologous) blood stem cells to rebuild the immune system. Blood stem cells, known as haematopoietic stem cells, are a type of adult stem cell found in the blood and bone marrow, and can generate new blood and immune cells.
The procedure involves:
- Pre-treatment to release bone marrow stem cells into the blood
- Collecting or ‘harvesting’ the autologous hematopoietic stem cells (AHSCs) from the blood of the patient
- Freezing (cryopreserving) the AHSCs in the laboratory until they’re required
- Administering chemotherapy to kill the patient’s current immune system (conditioning)
- Returning the thawed AHSCs to the patient by infusion into the veins, to try and repopulate the immune system
- High intensity supportive medical treatment is provided during and immediately after the transplant, when there’s a high risk of infection and bleeding disorders due to the intense immune suppression.
How does AHSCT work in MS?
In MS, the immune system mistakenly attacks the brain and spinal cord. The aim of AHSCT for MS is to ‘reboot’ the immune system, so that the “self-reactive” immune cells that are attacking the nervous system are removed and replaced with the regenerated immune system. This rebooted immune system is thought to be more ‘self-tolerant’ and less likely to continue attacking the body.
AHSCT is essentially a very powerful anti-inflammatory treatment, so it stands to reason that it might be most effective in situations where there’s a lot of active inflammatory activity, which we see most in relapsing remitting MS (RRMS) with relapses and active inflammatory lesions on an MRI (magnetic resonance imaging), and less in progressive MS with no inflammatory features. If no inflammation is present, then AHSCT may not be very helpful, as the stem cells involved in this treatment can’t repair the previous damage to nerves and myelin.
AHSCT, DMTs and MS
Let’s consider some of the reasons why AHSCT needs to be well-thought out and directed to those for whom, it might be the most effective and safe treatment.
Most disease modifying therapies (DMTs) for MS are relatively simple to administer in the big scheme of things. Obviously, taking a capsule or tablet is the least troublesome. Training for and administering self-injections at home, pushes the difficulty factor up another notch in terms of effort and inconvenience. Needing to go into a hospital day-only clinic or ward and having an intravenous (IV) line inserted for an infusion, takes it up yet another level of inconvenience and complexity. There isn’t too much distress involved in any of these treatments most of the time; they’re relatively free of too much discomfort.
Besides these three methods of taking DMTs, there are also safety-monitoring responsibilities such as regular blood tests, eye tests for others and extra MRIs, depending on which therapy has been prescribed. For many people living with MS, the inconvenience of these treatments is deemed worthwhile, because the treatments work to reduce their relapses and disease progression and allow many facets of life to return to normal, or close to it. The benefits outweigh both the risks and the amount of bother it brings (the “bother factor”). For each step up the ladder, the MS healthcare team has had to carefully consider benefit and risk and what they feel is justified, according to each individual circumstance. Keeping you as both disease-free and safe as possible is paramount.
Now, we get to AHSCT. This is a whole other level of potential risk, anguish and effort than we have seen in MS previously. It really has created a whole new platform for people with MS, their loved ones and MS healthcare teams to consider, and has not been taken lightly by the neurology, immunology and haematology specialists, who have worked together to bring AHSCT to the treatment arena. AHSCT requires much careful preparation and there is more than reasonable potential for pain and distress during and after the procedures. However, for people living with very active inflammatory MS, which isn’t responding to standard DMTs, AHSCT might be the answer to future quality of life, and the chance to live the type of life they had planned.
AHSCT risks and benefits
The range of effects caused by AHSCT haven’t been seen in MS treatments before, and this has required careful consideration and planning. This includes the effects of the large-dose chemotherapy in general and the substantial inherent infection risk, as well as the fertility risks on male and female patients, as both the testes and ovaries are affected by the treatment. After stem cell harvest and the very large dose of chemotherapy to destroy the faulty immune cells, the risk of infection is very high, and patients must isolate for several weeks to protect themselves.
The good news is that since 2005, the risk of death from AHSCT has gradually decreased, with recent research reporting a risk of less than 1%, compared to about 3% a decade ago. This is due to several reasons, including improved chemotherapy regimens, improved prevention and treatment of infections, the knowledge gained from past patients and improved selection of the patients most likely to recover well and to benefit from the procedure. Additionally, many MS specialists and scientists from all over the world contribute their patient progress information to registries, to gather more knowledge and to help build a profile of the type of MS patients who most benefit from AHSCT. This helps to keep the risk-to-benefit balance in check and to continually educate the MS community on the best and safest practice. For those living with active inflammatory MS not responding to standard treatments, AHSCT could be part of the treatment discussion they need to consider, to change their current MS pathway.
For more information on AHSCT and MS, click here.
