How Safe Are Stem Cells?

Stem Cell RiskHow safe are adult stem cells? This has become a hotly debated argument. There are financially conflicted scientists who frequently cry wolf over the safety of adult stem cells. Taken from your own body, then expanded to a therapeutic dose, mesenchymal stem cells are showing promise for treating many previously incurable illnesses. Why the objections? Theses scientists hold patents in, or receive grant money for, embryonic or IPSC stem cell research, which could be threatened by this safer therapy, already in use and saving lives today.

Paul Knoepfler, PdD, a scientist at UC Irvine pursuing induced pluripotent stem cell (IPSC) research, is one of these critics. In his blog he challenges patients who have had adult stem cell treatment: Critically reading science papers: response to patient on MS stem cell literature.

As evidence of danger, he presents 3 reports covering 9 patients that had adverse outcomes.

Patients For Stem Cells conducted some fact checking. We found 66 studies in, showing there have already been over 2,154 patients treated with their own EXPANDED mesenchymal stem cells. These reports consistently conclude treatments were well tolerated, with little to no side effects other than transient fever, and that further research is warranted. This is evidenced by the 1,630 patients in 54 EXPANDED mesenchymal stem cell trials currently underway, listed at

See our report on these findings How Safe Are Stem Cells?.

Arnold Caplan, PhD, from Case Western Re serve University and a leader in stem cell science has recently stated that more than 250 mesenchymal stem cells trials are ongoing or completed. The 120 trials we found are a subset of this larger number, because we limited our search to expanded or cultured cells, since this is what the critics have been crying wolf over, and calling for the FDA to withhold this life saving therapy from patients.

We challenge the critics to disprove the growing evidence base that shows adult stem cell therapy is safe.

Samantha Wilkinson,
Member, Patients for Stem Cells

6 thoughts on “How Safe Are Stem Cells?

  1. Kelvin Brockbank

    The question for me is not adult stem cell safety, rather it is efectiveness. That is assuming that manufacturing and delivery are performed under appropriate conditions.

  2. marierhodesrn

    Dr Brockbank, thank you for your comment.   It is good you acknowledge safety is not the issue-we agree.
    Efficacy is another issue and generating data regarding this is years out by the traditional large RTC route–there are no large stage III trials for autologous adMSC underway in the trial data base.  The closest was the Osiris trial for Prochymal but that is allogenic and commercial.  Therefore even if Patients for Stem cells won powerball today and started an autoMSC trial, we’d be at least 5 years from RCT proof of efficacy.
    As it is by the end of 14 we should see a paper or two published on smallish numbers in the few ph II trials that are enrolling now, but they are not big enough for robust efficacy data.
    Does it really make sense that people who are in the most dire situation must sit on their hands because other people don’t know if therapy will work for them?  I argue the position is inherently hypocritical because even if dozens of studies were done and it was very effective in trials, the patient STILL doesn’t know if it will work for him until he does it.  All that happens for the patient in this situation is he loses years–even a decade or possibly his life–waiting for trials to be done.  They offer little advantage to him as the only trial that matters is his own n=1.
    The “it might not work” argument loses its value on an individual level and is cruel when the person has no other therapies.
    We’d like to see people inside the industry support allowance of this therapy .  Please support patient access to autologous expanded-so they are therapeutically relevant–doses of MSC.  The FDA is not capable of releasing it without ample expert support and without a large corporate sponsor to pay for large RTC it will languish.  
    Prochymal is available under expanded access for patients with GVHD for compassionate use even though the efficacy trial failed to meet its endpoint.  Those patients are allowed to try it and see if it works for them when all else has failed.  Those are expanded allogenic MScells in clinically relevant doses.  Yet my OWN MSC can’t be allowed for my use when I have no options?  What is wrong with this picture?
    If the issue is lab standards–OK let the labs have standards. That is an accreditation issue and solvable inside of a year.  Let’s agree patients who need therapy should have access–let’s solve this!

  3. stemcellboss

    Safety of Intravenous Infusion of Human Adipose Tissue-Derived Mesenchymal Stem Cells
    in Animals and Humans
    Volume 20, Number 8, 2011
     Mary Ann Liebert, Inc.
    DOI: 10.1089/scd.2010.0466

    Adipose tissue-derived mesenchymal stem cells (AdMSCs) represent an attractive and ethical cell source for stem cell therapy. With the recent demonstration of MSC homing properties, intravenous applications of MSCs to cell-damaged diseases have increased. In the present study, the toxicity and tumorigenicity of human AdMSCs (hAdMSCs) were investigated for clinical application. Culture-expanded hAdMSCs showed the typical appearance, immunophenotype, and differentiation capacity of MSCs, and were genetically stable at least 12 passages in culture. Cells suspended in physiological saline maintained their MSC properties in a cold storage condition for at least 3 days. To test the toxicity of hAdMSCs, different doses of hAdMSCs were injected intravenously into immunodeficient mice, and the mice were observed for 13 weeks. Even at the highest cell dose (2.5·108 cells/kg body weight), the SCID mice were viable and had no side effects. A tumorigenicity test was performed in Balb/c-nu nude mice for 26 weeks. Even at the highest cell dose (2·108 MSCs/kg), no evidence of tumor development was found. In a human clinical trial, 8 male patients who had suffered a spinal cord injury >12 months previous were intravenously administered autologous hAdMSCs (4·108 cells) one time. None of the patients developed any serious adverse events related to hAdMSC transplantation during the 3-month follow-up. In conclusion, the systemic transplantation of hAdMSCs appears to be safe and does not induce tumor development.

  4. TomShepherd

    Great post Sammy Jo.  You’re sounding a little fired up … and I like it.

Comments are closed.