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Japan must tighten up clinical trial of stem cells for heart failure

University of Tokyo, Japan.
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University of Tokyo, Japan.

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University of Washington School of Medicine, Seattle, Washington, USA.

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A task force in Japan’s health ministry has conditionally approved the world’s first clinical trial to treat patients with heart failure, using sheets of heart-muscle cells derived from ‘reprogrammed’ adult stem cells (Nature 557, 619–620; 2018). In our view, two aspects of the trial protocol need to be addressed before it can be fast-tracked (see also Nature 557, 611–612; 2018 and Y. Yui npj Regen. Med. 3, 7; 2018).

First, we question the trial’s use of allogeneic induced pluripotent stem (iPS) cells, called iPS stock cells and prepared by Kyoto University’s Center for iPS Cell Research and Application. This use of heart-muscle cells from different donors could trigger transplant rejection by the patient. And using immunosuppressants to prevent rejection can cause unpleasant side effects, including a risk of promoting tumour development. We suggest that such risks be minimized by using autologous (that is, the patient’s own) iPS cells in the trial instead.

Second, the task force has specified that the trial should involve three participants with “more serious” heart failure than was proposed in the submitted trial protocol. In our view, it would be better to recruit people who are less severely affected, given that the trial’s main goal is to establish the procedure’s safety. The intervention involves open heart surgery and is medically intensive, so by itself could kill those who are more vulnerable. This would also prevent proper evaluation of the stem-cell treatment.

Addressing these scientific and ethical concerns will ensure that the clinical trial amounts to more than a compassionate rescue attempt.

Nature 560, 431 (2018)

doi: 10.1038/d41586-018-06015-x
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