We’ve all been closely following Geron and its work on ES cells.
This morning there was a fantastic session here at the ASGCT meeting in Seattle on Clinical Trials on Stem Cells.
Talk by Geron
One of the speakers was Geron VP, Jane Lebkoswki, PhD: Development of Human Embryonic Stem Cell-Based Therapies for Treatment of Human Degenerative Diseases.
The talk was focused on OPC1 for the treatment of spinal cord injury.
Dr. Lebkowski said there were three main potential functions of OPC1: (1) stimulation of neurite outgrowth, (2) re-myelination, and (3) neovascularization.
She gave an update on the first patient to receive OPC1 with all indications being positive that he has suffered no negative outcomes from the treatment up to this time, which is very encouraging. As to efficacy, we will have to wait and see.
Teratoma and safety
I thought one of the other interesting points she made was that not only were there no teratoma observed with OPC1 in pre-clinical trials, but also even when they spiked in pure human embryonic stem cells into OPC1, it still took some doing to get teratoma. Mixtures of 95% OPC1 and 5% pure ES cells gave no teratoma. Teratoma became detectable at a low rate only when ES cells constituted 10% of the spiked mixture. What this says is that if even if OPC1 were not perfectly pure, which it isn’t (she mentioned that a few % of cells were other types), and some ES cells remain, it would take a lot to generate teratoma. She quoted the figure of a minimum of 100,000 ES cells to form a human teratoma. Of course, we do not know that this is definitely the case in the context of a human recipient, but it is encouraging.
In addition, she mentioned that of the other undesired cells in OPC1, the main types were neurons but also a few fibroblasts. I have never heard this specifically mentioned before so I thought that was interesting.