Pluripotent Stem Cell Expansion and Differentiation

A potential functional cure for type 1 diabetes

The potential for cell replacement therapy to effectively treat type 1 diabetes has already been demonstrated by way of donor islet transplant. Despite the demonstrated efficacy of donor islet transplant, this procedure is reserved for the most high-risk patients because of the limited supply of donor (cadaver) islets and the requirement for immunosuppression. We believe that ViaCyte’s breakthrough technology and cell replacement product candidates can address the limitations of donor islet transplants and become a major advancement in the treatment of diabetes.

Pluripotent stem cells could solve the supply issue

ViaCyte is focused on pluripotent stem cells (PSC) due to 1) their exceptional capacity to expand to large numbers and 2) the ability to direct their differentiation into various potentially therapeutic, specialized cell types.

Stem cell expansion

For cell expansion, ViaCyte has developed an understanding of the signals that instruct pluripotent stem cells to undergo self-renewal without changing into more specialized cell types. ViaCyte spent many years developing advanced stem cell growth media and conditions for expanding as well as cryopreserving undifferentiated pluripotent stem cells, thus providing the necessary foundation for clinical and commercial scale-up and manufacturing of PSC-derived cell products.

Wordwide, ViaCyte has more than 550 patents and 400 patent applications covering the company’s breakthrough technologies.

Stem cell differentiation

Pluripotent stem cells hold the potential to generate any cell type present in the body through sequential steps of specialization. Because of this potential, the very first steps of the differentiation process are critical to control in an efficient and homogeneous manner.

For stem cell differentiation, based on published scientific studies, ViaCyte scientists were the first to perform directed differentiation of human pluripotent stem cells into definitive endoderm, the gatekeeper cells that can further differentiate into pancreas, liver, and other cells, tissues, and organs.

By leveraging the studies of developmental biology, ViaCyte invented a reproducible, patented, multistep process for differentiating pluripotent stem cells into pancreatic endoderm cells (also known as pancreatic precursor cells; PEC-01 cells). The process mimics the natural development of the human pancreas. During each step, prescribed types and amounts of growth factors, growth media, and supplements direct pluripotent stem cells to progress along the differentiation pathway until they become PEC-01 cells. Once implanted under the skin of a patient, PEC-01 cells, which are contained within an implantation device, have been designed to mature into functional beta cells and other cells of the islet that control blood glucose levels.


ViaCyte’s PEC-01 manufacturing process takes about 30 days and was developed to reliably produce PEC-01 cells from pluripotent stem cells.

ViaCyte’s CyT49, a proprietary, well-characterized pluripotent stem cell line

ViaCyte has a proprietary pluripotent stem cell line, called CyT49, derived under strict ethical guidelines, which has beneficial properties for the efficient production of PEC-01 cells. We have generated and qualified large-scale master and working cGMP cell banks of the CyT49 line. This has provided us with a single cell source that is thoroughly characterized. Through years of work by our scientists who are leaders in this field, we have developed novel proprietary processes and technologies that allow us to maintain these cells in a state of pluripotency and purposefully manufacture a desired cell type in large-scale production.

Since PEC-01 cells are made from a pluripotent stem cell line (CyT49), there is a potentially unlimited supply available for manufacturing ViaCyte’s product candidates.

ViaCyte’s product candidates are different from stem cell treatments

ViaCyte does not deliver stem cells as a product. ViaCyte uses pluripotent stem cells as a starting material to make its cell products. In fact, ViaCyte goes to great lengths to ensure stem cells are not present in its product candidates. PEC-01 cells are called pancreatic precursor cells, but they are not stem cells. They are fully committed to further differentiate into mature pancreatic cells, including insulin-producing beta cells as well as other pancreatic cells that express glucagon, somatostatin, amylin, and other hormonal factors that regulate blood glucose.

Pluripotent stem cells Adult / stromal fraction stem cells
Not a treatment ‘Stem cell treatment’
Can make any cell type Only makes bone, blood, fat
Unlimited proliferation Limited proliferation
Starting point for ViaCyte product candidates ViaCyte does not use
hESC, iPSC MSC, ASC

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