San Diego-based ViaCyte said today it is collaborating with W.L. Gore & Associates, the privately held company that makes Gore-Tex fabrics, medical devices, and other products, in a bid to improve its stem cell-derived treatment for diabetes.
Under their collaborative research agreement, ViaCyte said it will work with Gore to develop a next-generation version of the bio-engineered packet that ViaCyte fills with stem cells that have been engineered to become pancreatic cells. The packet, currently about the size of a stick of gum, is designed to be implanted just under the skin.
When ViaCyte reported preliminary results from its initial clinical trial just over a year ago, the company said it had successfully shown that its stem cells would differentiate and grow into pancreatic islet cells that produce insulin and other pancreatic hormones three months after implantation. ViaCyte also released the photo above, showing how tiny blood vessels had grown across the outside of a packet, which ViaCyte calls the Encaptra Cell Delivery System. (For the record, the image is from animal studies.)
The genius of ViaCyte’s approach is that insulin and other regulatory hormones can get out of the packet through the semi-permeable membrane, but white blood cells are too big to penetrate the membrane to attack the foreign pancreatic cells. The packet protects the implanted pancreatic cells from a patient’s own immune system.
However, in an interview earlier this week, ViaCyte CEO Paul Laikind said insulin and other pancreatic hormones produced by the stem cell-derived islet cells inside the packet aren’t being absorbed as efficiently as expected. In Laikind’s words, “engraftment was not as positive as we wanted it to be.”
The ViaCyte CEO likened the bio-engineered packet to a tea bag, and he said the hormones produced inside the packet pass through the membrane the way tea seeps out of a tea bag. But Laikind said the diffusion process that enables these hormones to get absorbed by blood vessels isn’t robust enough.
So ViaCyte started working with Gore last year to improve how blood vessels grow across the membrane of the bio-engineered packet. “We needed to improve the ability to vascularize across the surface of that membrane, and that’s where Gore comes in,” Laikind said.
ViaCyte has been developing what it calls the PEC-Encap product candidate to deliver stem cell-derived islet cells to patients with type 1 diabetes as well as patients with type 2 diabetes who require insulin.
Meanwhile, Laikind said ViaCyte has been developing another product, called PEC-Direct, that would provide the same type of stem cell-derived islet cells to high-risk diabetic patients in a packet that is not intended to protect against the patient’s immune system. These patients would have to also get immune-suppressant drugs, Laikind said.