#ThinkSpeak: we need to make sure science happens the way it is meant to happen

Has HSCT become the new CCSVI? #ThinkSpeak

Summary: This post summarises the current scientific perspective of HSCT and attempts to put it as a treatment for MS into perspective. 

Like most modern treatments that get adopted prematurely in MS, i.e. before the necessary science is done to convince the wider community, they are driven by social media. We have a lot of experience on this blog with CCSVI; in fact, CCSVI is one of the main reasons why I started this blog. 

The question I now find myself asking has HSCT become the new CCSVI? Could the current support for HSCT as a treatment for MS getting ahead of the curve? Is the HSCT movement in MS becoming an anti-science movement, i.e. adopted against the predominant scientific opinion of the time? The wider MS community, pwMS, neurologists, scientists, charities, healthcare systems, etc. have agreed that there is a place for HSCT in the treatment of MS, but until we have better evidence of its relative benefits and risks compared to licensed DMTs we should be limiting HSCT to patients with more active MS who have failed at least one (high-efficacy), or two, established DMTs. In direct opposition, there are a group of HSCT-supporters who disagree and want everyone with MS to have the option of being treated with HSCT first-line. The latter recommendation is not supported by the science/data.

Sociological studies have identified 4 main social drivers of anti-science movements: 
  1. The ‘dissident scientists’ who lends credibility to the theory. 
  2. The ‘cultropreneurs’ who peddle the therapy. 
  3. The ‘living icons’ and ‘miraculous responders’ who have been treated. 
  4. The ‘praise-singers’, ‘journalists’ and ‘politicians’ who promote the theory 
I agree that HSCT looks like a very effective treatment for MS. Does it cure MS? No, we can't make that claim yet. Cohorts of HSCT-treated pwMS have not been followed long enough to justify this claim. Is it better than established or licensed DMTs? Possibly, indirect comparisons suggest it might be, but until we have head-2-head studies we can't make that claim. Is it safer than established DMTs? It depends on what you are comparing it with and the specific outcome. For example, when it comes to the risk of neutropenic sepsis it is riskier than licensed therapies. Similarly, it has a much higher risk of ovarian toxicity (premature menopause) than established treatments. Safety, or relative safety, is another reason why we need large head-2-head studies to define the risks better in well-controlled randomised trials of sufficient size.  

What should we tell pwMS? My message is simple. HSCT is a very effective therapy for treating MS. It has substantial risks associated with its use. We only offer HSCT to our patients who have active MS and have failed at least one high-efficacy DMT. We are however in the process of trying to obtain the necessary funding to compare the benefits and risk of HSCT to alemtuzumab. The latter is part of our scientific due diligence. 

It is, however, reassuring to note that in the UK the costs of HSCT under the NHS appear very reasonable compared to licensed treatments. This could potentially make it a very cost-effective option for treating MS in the future. There are well established local and regional guidelines for HSCT and NICE is trying to establish national guidelines. 

From a scientific perspective, we need to ask ourselves how HSCT is working? We think it is working via a B-cell mechanism, similar to other DMTs. If this is the case then do we need HSCT to achieve our therapeutic aims? Could we not get away with a more selective IRT (immune reconstitution therapy) that has a better safety profile? Clearly the latter would be much safer. The difference between scientists and anti-scientists is that we put forward testable hypotheses and they put forward beliefs. Unfortunately, it is difficult to challenge beliefs and you can't test them in a scientific experiment.

I would urge anyone in England considering to travel abroad for HSCT to discuss your decision with your neurologist and MS clinical nurse specialist. If you are eligible for it under your local guidelines I would recommend having the treatment in England. The following are three relevant documents you may wish to read that we have published on the blog in the past.

1. London MS-AHSCT Collaborative Group eligibility criteria
2. The Bristol guidance document for pwMS considering HSCT abroad
3. NICE draft technology appraisal for HSCT as a treatment for MS in England.

CoI: multiple

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