“(Melton) raised concerns more specifically about the Encaptra capsule, for example, functionally becoming fibrotic and mentioned worries about your cells being immature and taking a long time to mature. Any response on capsule and cells? He also has suggested that his beta cells will be a better option.”
“Dr. Melton’s work on the beta cell is very interesting. As to the cells, we made the choice to use the pancreatic progenitor cells. An important consideration is that when you first put in cells, they are in a hypoxic environment. Beta cells are sensitive to low oxygen levels, which can negatively affect their survival and function. Beta cells typically exist in a mature highly vascularized organ. The pancreatic progenitor cells that we use undergo an organogenesis-like process, more similar to how they behave in nature, and thus we believe they should be better able to handle low oxygen. They also are believed to release angiogenic and other factors to promote vascularization.
“In regards to the capsule, we do expect there to be a foreign body reaction in patients after implantation, which will generate a fibrotic capsule. In fact, we see a thin fibrotic capsule around the device in mice. But in the mouse model this capsule around the device is very well vascularized. The vasculature is right up against the device membrane on the outside, allowing for oxygen and nutrient diffusion to the cells inside.”
“There’s room in this area for multiple efforts and we aren’t especially concerned with competition. Yet we do feel we are ahead of others and we have substantial intellectual property that they will need to navigate (~50 patents issued in the United States, and a couple hundred pending patent applications, including international). At ViaCyte we view the real competition as the biology rather than with the efforts of others as we seek to cure this devastating disease.”
“The reason for that placement is that while the device can withstand the impact of a 60 mph baseball (based on cadaver testing), a needle could go right through it, so we want to put it where patients don’t typically inject insulin.”
“Douglas Melton, a biologist at Harvard University who has two children with type 1 diabetes, worries that the ViaCyte system may not work. He thinks deposits of fibrotic, scarlike tissue will glom onto the capsules, starving the cells inside of oxygen and blocking their ability to sense sugar and release insulin. Melton also thinks it might take immature cells up to three months to become fully functional. And many won’t become beta cells, winding up as other types of pancreatic cells instead.
“Melton says the ‘inefficiency’ of the system means the company ‘would need a device about the size of a DVD player’ to have enough beta cells to effectively treat diabetes. ViaCyte says it thinks 300 million of its cells, or about eight of its capsules, would be enough. (Each capsule holds a volume of cells smaller than one M&M candy.) Last October, Melton’s group announced it had managed to grow fully mature, functional beta cells in the lab, a scientific first that took more than 10 years of trial-and-error research. Melton thinks implanting mature cells would allow a bioartificial pancreas to start working right away.”