Although research into stem cell therapies continues to advance, the field faces a growing threat that could undermine this progress. The internet-based stem cell tourism industry offers patients the hope of a cure for incurable diseases, often with unproven, unregulated treatments provided at clinics overseas or, increasingly, in the United States.1 As advertisements for such therapies proliferate, neurologists treating patients with multiple sclerosis (MS) may encounter this issue in clinical practice, with patients seeking guidance and clearance for these treatments or having already undergone such procedures.
Legitimate Stem Cell Research in MS
In the legitimate research realm, several cell-based therapies for multiple sclerosis have advanced to clinical trials.2,3 For example, immunoablation followed by autologous hematopoietic stem cell transplantation aims to support regeneration of the immune system in patients with MS. Although early findings suggest efﬁcacy in reducing relapses and magnetic resonance imaging lesion activity in relapsing-remitting MS, there are significant safety concerns associated with the procedure thus far.
Mechanisms underlying additional cell-based therapies being investigated for MS include “modifying both immune reactions and endogenous repair mechanisms using mesenchymal stem cells (MSCs) and other stem cells from bone marrow, adipose tissue, placenta, or other tissues; pharmacologic manipulation of endogenous stem cells to enhance their reparative capabilities; or replacing damaged or lost myelin-making oligodendrocytes by transplantation of oligodendrocyte progenitor cells (OPCs) or OPC-like inducible pluripotent stem cells,” wrote the authors of a 2017 review published in Brain.2 Initial results indicate that these procedures may provide the most benefit for patients with progressive forms of MS, although further investigation is needed.
Stem Cell Pseudoscience
Meanwhile, the growing practice of stem cell pseudomedicine “is becoming a highly profitable enterprise predicated on the lack of knowledge, guidance, and counseling of patients and their families who are desperate for a cure for devastating and incurable neurological diseases,” according to a paper published in 2015 in JAMA Neurology.1
“The implications of the stem cell tourism industry for the legitimacy of and public confidence in stem cell research are enormous.”
Companies touting these therapies may use impressive websites with endorsements by celebrities and physicians to instill a sense that the procedures are safe and acceptable. In addition, some companies claim to have “observational cohort” studies underway, which enables them to register at clinicaltrials.gov, further increasing the appearance of legitimacy to patients and even physicians.
However, there is accumulating evidence of substantial morbidity and mortality associated with these unregulated treatments. Among numerous such reports, a German clinic was shut down after 2 pediatric patients died as a result of intracranial bleeding after stem cell injections, and other patients have developed tumors believed to be linked to stem cell treatment.1
To learn more about issues surrounding stem cell tourism and how physicians should address this topic in clinical practice, Neurology Advisor interviewed Jeffrey A. Cohen, MD, director of the experimental therapeutics program at Cleveland Clinic’s Mellen Center for MS Treatment and Research in Ohio.
Neurology Advisor: Is stem cell tourism still a relevant issue for physicians treating patients with MS? What is your opinion about this practice?
Dr Cohen: Although we have made great progress in treating relapsing MS, and medications to treat progressive MS are starting to emerge, better treatments for progressive MS and strategies to restore lost function remain major unmet needs. There is a great deal of interest in cell-based therapy to meet those needs. However, although cell-based therapy holds great promise, at present it has unproven benefit and incompletely defined safety. Despite those uncertainties, an increasing number of free-standing clinics offer stem cell therapy, and patients continue to seek them out. So, yes, stem cell tourism continues to be a significant issue for physicians treating MS and other disorders.
Neurology Advisor: What are some of the problems associated with this practice?
Dr Cohen: The main problems are:
- Our current incomplete scientific knowledge about a wide range of very fundamental technical factors concerning cell-based therapy: optimal source of the cells, or from where in the body they should be isolated and whether they should come from the patient themselves or someone without the disease; cell production methods to optimize the therapeutic benefit; dose, or how many cells to administer, route of administration of the cells, and how often the cells need to be administered; potential complications, including how often and when they occur, and so on. With all these unknowns, it is premature to offer cell-based therapies as part of routine medical practice.
- Many patients and clinicians do not fully appreciate that there are many types of stem cells, methods for producing them, ways of administering them, and conditions for which they have been tried, all with different issues. As a result, one cannot merely talk about stem cells in general. All those issues listed here need to be worked out for every different stem cell approach and every indication.
- Lack of regulatory oversight of facilities administering what should be considered an experimental medical therapy to make sure the cell product is not contaminated and is viable, and that what the facility claims to be doing actually is being done to assess benefit, to monitor for complications, and so on.
- Having patients pay out of pocket for an expensive therapy, with them often not realizing it is completely unproven, is probably not helpful, and is occasionally dangerous.
Neurology Advisor: What recommendations would you offer to clinicians regarding how to advise patients inquiring about stem cell tourism?
Dr Cohen: They should advise their patients that although cell-based therapy holds great promise, it currently is experimental with unproven benefit and incompletely defined safety. Stem cell therapy should only be pursued in the context of formal research studies. Clinicians should express that they understand the patient’s desire to pursue a therapy that potentially might help them and the feeling of “What do I have to lose?” At best, they probably are wasting their money. At worst, there may be serious complications, as has happened in some cases.
Neurology Advisor: What should be next steps in the field of stem cell research?
Dr Cohen: There is a great deal of interest in developing cell-based therapeutic strategies for MS and many other conditions. That research is making progress and needs to continue. In the meantime, it is premature to offer stem cell therapy as part of routine medical care. There are well-defined criteria for what is acceptable to the US Food and Drug Administration for using stem cells as part of the practice of medicine and what should be considered experimental, and how experimental treatments should be used.4
Dr Cohen recommends referring patients to the National MS Society website for useful information about stem cell therapy for MS.
- Bowman M, Racke M, Kissel J, Imitola J. Responsibilities of health care professionals in counseling and educating patients with incurable neurological diseases regarding “stem cell tourism”: caveat emptor. JAMA Neurol. 2015;72(11):1342-1345.
- Scolding NJ, Pasquini M, Reingold SC, Cohen JA. Cell-based therapeutic strategies for multiple sclerosis. Brain. 2017;140(11):2776-2796.
- Baldassari LE, Cohen JA. Mesenchymal stem cell-derived neural progenitor cells in progressive multiple sclrosis: great expectations. EBioMedicine. 2018;29:5-6.
- US Food and Drug Administration. Regulatory considerations for human cells, tissues, and cellular and tissue-based products: minimal manipulation and homologous use. https://www.fda.gov/downloads/BiologicsBloodVaccines/GuidanceComplianceRegulatory
Information/Guidances/CellularandGeneTherapy/UCM585403.pdf. Accessed August 27, 2018.