Thursday, July 6, 2017

CIRM Sponsored Clinical Trial Program Notable for Near Lack of hESCs

The California Institute of Regenerative Medicine (CIRM) is nearing the end of its ten year term.  Debate in California is ongoing as to whether CIRM will actually close, or whether it will continue in a different form with different funding sources.

The Alpha Stem Cell Clinics Network program may very likely be one of the last major initiatives CIRM takes before its current term is over sometime this year.  As such, it is emblematic of the funding course CIRM has travelled over the years.

The Network’s goal, according to CIRM, “is to accelerate the development and delivery of stem cell treatments to patients.”  To do this, CIRM authorized the creation of up to 5 alpha clinics.  These clinics are to be set up at academic institutions across California in order to serve as a “hub for stem cell clinical trials.” So far, three such clinics have been established, housed at City of Hope, University of California/San Diego, and UCLA/UC Irvine.

Earlier this year, at City of Hope, the Network held its second annual symposium, where patients and doctors met to discuss ongoing research and review progress in clinical trials underway.

At the time the symposium was held, there were 36 CIRM-funded Alpha Stem Cell Network clinical trials underway, spread across the three already established alpha clinics.

This blog has called attention to the way that CIRM – founded to give priority funding to human embryonic stem cell research – has over the years been providing the lion’s share of its grants to adult and other non-embryonic stem cell research.

A look at the Alpha Stem Cell Network clinical trials shows the same pattern of funding that has come to characterize so many of CIRM’s grants: away from research using human embryonic stem cells (hESCs) in favor of research using adult and other non-embryonic stem cell alternatives.

Only two of the trials listed on CIRM’s website utilize hESCs. However, they are really the same trial, with two different phases, so out of the 36 ongoing alpha network trials, only one is using hESCs.  Moreover, although utilizing such cells, they are not even the main focus of the trial.[1]

The trial is being conducted by a company called ViaCyte.  ViaCyte is testing a device it is developing that is intended to be placed under a patient’s skin, in order to deliver pancreatic progenitor cells derived from hESCs.  So the focus of the study is the performance of the device, not the efficacy of the stem cells it delivers for treating diabetes.

But should the device prove to be successful, it could deliver non-embryonic derived stem cells useful for treating diabetes as well.

For example, Harvard researcher Doug Melton has produced identical sets of mature, insulin producing beta cells from both hESCs and non-embryonic, induced pluripotent stem cells.  So if a device such as Viacyte’s should prove successful in delivering cells, it could just as well deliver ethically non-contentious, non-embryonic derived cells capable of treating diabetes.[2]

In fact, Melton is himself working on his own version of such a device.  Moreover, Melton has expressed concern that because the cells being used by ViaCyte to test its device are embryonic-derived progenitor cells, not yet fully differentiated to produce insulin, the cells may take months to mature into true insulin producing cells.  He has also expressed concern that not all the progenitor cells will necessarily develop into insulin producing ones, but rather could develop into other types of pancreatic cells.  Thus, while the device itself may prove efficacious, the embryonic stem cell derived progenitor cells it is intended to deliver may be far less so. 

So as CIRM nears the completion of its original term, the grants it has made to the Alpha Clinic Stem Cell Network are again confirming that adult and other non-embryonic stem cells would appear to be showing the most promise for helping patients.

[1] Eight of the trials used adult stem cells and three iPSCs.  Three used cells derived from fetal tissue, which are considered adult stem cells, but which raise their own ethical issues. The remaining trials are a mix consisting of the use of the patient’s own cells and gene therapy.
[2] In 1999, then-President Clinton’s National Bioethics Advisory Commission became the first such body to investigate the ethical issues surrounding human embryonic stem cell research.  NBAC made pursuit of the research conditional: harvesting “left-over” IVF embryos for stem cells “is justifiable only if no less morally problematic alternatives are available for advancing the research (at pg. 53).”  In this instance, it would seem there are indeed ethical alternatives to ViaCyte’s embryonic stem cell-derived progenitors. 

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