Mesenchymal stem cell therapy in clinic: current status and problems

by Alexey Bersenev on April 13, 2010 · 4 comments

in clinical trials and cases,reviews

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The very recent review by James Ankrum and Jeffrey Karp: Mesenchymal stem cell therapy: Two steps forward, one step back, summarizes the current status of clinical mesenchymal stem cell therapy and analyzes the problems which these trials are facing.

Mesenchymal stem cell (MSC) therapy is poised to establish a new clinical paradigm; however, recent trials have produced mixed results. Unfortunately, although clinical trials have met safety endpoints, efficacy has not been demonstrated. We believe the challenge to demonstrate efficacy can be attributed in part to an incomplete understanding of the fate of MSC following infusion.

I really like this review, because it’s very analytical and up-to-date. I’d like to highlight some very important points made in the review. First of all they did a great job, summarizing all current clinical trials using MSC.

numbers

They concluded that there are at least 101 trials total launched and available for analysis (based on submissions to www.ClinicalTrials.gov), including 59 allogeneic MSC transplantation and 42 – autologous; 21 trials were completed at the moment; total number of patients treated – 5344. Countries that contributed most in total number of trials: USA – 31; Europe overall – 22; China – 16. Authors made an excellent detailed table summarizing all of trials. Most frequent indications: bone/cartilage diseases – 26 trials; cardiovascular diseases – 19; GvHD – 16; neurology – 12.

clinical trials start to meet some problems on phase II-III

Safety – phase I of clinical trials usually go smoothly in every indication, but when the trials reach phase II and especially randomized placebo-controlled studies, we start to see more mixed results and failures. For example – Osiris Prochymal trial for GvHD phase III.

Although the mixed clinical data could be considered a major setback to the entire MSC field, these trials extended initial phase I safety data to thousands of patients, and we believe this should be considered a critical milestone, particularly given that typical doses include hundreds of millions of allogenic MSC. It is also important to consider that it took several decades to optimize bone marrow transplantation before it became a standard of care.

paradigm shift in understanding of therapeutic efficiency

    - moving focus from the therapies based of MSC differentiation capacity to trials which focused on MSC trophic function (direct differentiation mechanisms versus paracrine, endocrine functions and immunomodulation);
    - very low homing and engraftment rate (below 1%) and entrapment in the lungs favors indirect – trophic mechanisms and immunomodulation function versus differentiation in mesenchymal lineages.

Unlike conventional drugs, which are designed to act through a known pathway, cell therapies are living therapeutics, which can multiply, senesce, undergo necrosis or apoptosis, or alter their phenotype, and thereby drastically change their therapeutic potential.

challenges in basic biology

    – nomenclature (correct name of MSC);
    - characterizing and defining the MSC phenotype (too many different markers proposed – leads to lack of standardization);
    - heterogeneity and comparison populations between tissues and withing one tissue.

future development

    – monitoring of fate and tracking migration of MSC after transplantation;
    - local delivery to specific tissue when there is an indication;
    - better characterization of MSC and cell culture conditions for isolation of therapeutically relevant cells.

ClinicalTrials.gov registry currently lists 101 trials that are using exogenous MSC to treat a wide range of damaged, diseased or inflamed tissues. Because only 21 of these trials have been completed, we can anticipate an abundance of new human data in the near future for a wide range of therapeutic applications (21 trials are scheduled to be completed in 2010 and 20 trials in 2011). Through investigation of MSC biology, discovery of their therapeutic mechanisms within animal models and testing their therapeutic potential within human trials, we will hopefully achieve many more steps forward to make MSC therapy a new clinical paradigm.

Very good review. Highly recommended to read!

Related posts:

  1. Co-transplantation of mesenchymal stem cells in leukemia clinic – caution!
  2. Cell therapy clinical trials 2009 – part III
  3. How soon will human embryonic stem cells jump to the clinic?
  4. The leukemic stem cell niche: current concepts
  5. Cell therapy clinical trials 2009 – part II

{ 4 comments… read them below or add one }

Dr M.Chandrashekhar April 14, 2010 at 3:11 am

Great Report. I appreciate the the honest & frank approach in this report. Elsewhere, especially from India, we were getting exaggerated reports on the efficacy of MSCs.

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Alex April 14, 2010 at 12:06 pm

Dr M.Chandrashekhar, we can’t wait updates from India. I hope it will go much faster than in US.

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Dr M.Chandrashekhar April 15, 2010 at 12:21 am

Alex,

Though we have good. regulatory authorities for Clinical Trials in India, I feel, many trial reports are not so open– drawbacks are not highlighted.

There is also a sort of race to start MSCs as treatment modality by fly by night hospitals though Clinical Trials have yet not given a green signal.

Reply

Jim H April 15, 2010 at 3:23 pm

Dr M,

We have the same issues here. In the States we call these people “Snake Oil Salesmen”.

interestingly, in the numbers you posted, America is leading the world in Clinical trials, but presume this is only FDA approved trail and misrepresents the actual number of clinical trials by other Government sponsored Health agencies.

Great review Alex. Thanks.

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