PEC-Encap™ (VC-01™) – Improving Diabetes Treatment
The PEC-Encap™, also known as VC-01™, product candidate delivers PEC-01™ pancreatic progenitor cells in the Encaptra® immunoprotective device, and is currently being developed as a potential therapy for all T1D patients who have minimal to no insulin-producing beta cell function.
By acting essentially as a replacement endocrine pancreas, the source of insulin and other regulatory hormones produced in our bodies, ViaCyte’s PEC-Encap product candidate has the potential to be a functional cure for all type 1 diabetes patients.
What is the PEC-Encap Product?
The PEC-Encap therapy is the combination of:
- PEC-01 cells: A proprietary pancreatic endoderm cell product derived through directed differentiation of an inexhaustible human embryonic stem cell line, delivered in the
- Encaptra cell delivery system: A proprietary immune-protecting and retrievable encapsulation medical device.
The PEC-Encap product is implanted under the skin of the patient through a straightforward outpatient surgical procedure. The cells are designed to further differentiate into mature pancreatic cells that will synthesize and secrete insulin and other hormones, thereby regulating blood glucose, commonly referred to as blood sugar, levels.
The PEC-Encap Therapy is Effective in Pre-clinical Disease Models
The efficacy of the PEC-Encap product has been demonstrated in numerous pre-clinical studies and is illustrated in the following graph from a study performed in mice in accordance with Good Laboratory Practices (GLP). In this model, the PEC-Encap product or empty Encaptra cell delivery devices are implanted (the graph shows results from female mice; male mice demonstrate similar results).
Normal blood glucose levels for the mouse are typically 160 to 200 mg/dL, a level that would be considered hyperglycemic (high) in humans. Yet, as expected, animals that received the PEC-Encap product containing human PEC-01 cells have blood glucose closer to human levels (100 mg/dL) because it is being regulated by the grafted human cells (PEC-Encap group; blue line).
Further proof of the efficacy of the PEC-Encap therapy is seen when both groups of mice are treated with STZ, a chemical that selectively kills native mouse beta cells, at 33 weeks (arrow) after implantation. As expected, the animals implanted with devices loaded with PEC-01 cells (PEC-Encap product; blue line) maintain their blood glucose levels, while animals given empty devices without PEC-01 cells (Empty Device; green line) experience severe hyperglycemia.
The PEC-Encap Therapy Outlook
The targeted attributes of the PEC-Encap product include:
- Long-term control of blood glucose levels with a single minimally-invasive outpatient implant
- Insulin independence – blood glucose tightly regulated in the normal range, eliminating the need for insulin injections
- A significant reduction in serious chronic health conditions that are caused by years of insufficiently controlled blood glucose swings
- Significantly reduced risk of hypoglycemia
- Physiologic production of other pancreas-derived regulatory hormones and co-factors which have the potential to produce other health benefits
- Ability to terminate treatment by minimally invasive, outpatient removal of the encapsulated product, if needed
The Synergy of Cell Therapy and Medical Device
Like beta cells in the native pancreas, the glucose-sensing insulin-producing cells that develop from PEC-01 cells require a steady supply of oxygen and other nutrients to produce enough insulin to control blood glucose. PEC-01 cells are effectively a tissue transplant, which without protection would be rejected by the patient.
and ViaCyte’s cell therapy product
In this mouse study, host blood vessels have begun growing around the PEC-Encap combination product at 4 weeks.
At 8 weeks, vascularization is developing rapidly.
The Encaptra device is designed to prevent immune rejection by surrounding PEC-01 cells with a semi-permeable, protective membrane.
ViaCyte has demonstrated in pre-clinical models that the unique combination of these cells with this device results in rapid and extensive growth of blood vessels around the device, providing a plentiful oxygen source and rapid distribution of insulin to the body.
Preclinical Data are Promising
To date, over a thousand PEC-Encap pre-clinical study implants have matured into insulin-producing grafts. The PEC-Encap therapy has consistently been capable of controlling blood glucose in mice at a human set point.
After 16 weeks, PEC-01 cells have developed into islet-like structures.
The mature cells in the PEC-Encap™ product produce insulin, glucagon and somatostatin.
PEC-Encap Clinical Trial – STEP ONE Preliminary Update
ViaCyte received approval from the U.S. Food and Drug Administration (FDA) in August 2014 to begin evaluation in human clinical trials. The PEC-Encap clinical trial (STEP ONE* trial), underway at clinical centers in Canada and the USA, is evaluating basic safety and tolerability in patients with type 1 diabetes. See Clinical Trials.
It is early but observations so far indicate that PEC-Encap is safe and well-tolerated by patients. All trials have adverse events, and events observed in the STEP ONE trial have generally been those that would be anticipated, related to the surgical procedure, such as discomfort during a post-operative recovery period. To date no adverse events related to the implanted cells have been observed. The Encaptra® device appears to be immuno-protective as designed with no evidence of allo- or auto-immune activation or sensitization in patients to date.
The observations in the STEP ONE trial are encouraging, but further development to ensure effective engraftment in patients is needed. ViaCyte continues to make progress on reducing variability between patients and improving cell engraftment with the PEC-Encap product candidate. Towards this end, ViaCyte is collaborating with W. L. Gore & Associates, world leaders in implantable medical devices, to further develop novel implantable cell therapy delivery device technologies. Clinical observations with the PEC-Encap product candidate are also informing progress with development of the PEC-Direct product candidate.
*Safety, Tolerability, and Efficacy of VC-01 Combination Product in Type One Diabetes