We've been covering quite a few companies working hard at finding ways to protect islets from immune system attack. First we profiled Cerco Medical, which is also the subject of a documentary film, and a couple of weeks ago we checked in with ViaCyte, of San Diego. Both of those companies are working with stem cells, but today's company, Canada's Sernova, is kicking it old school by working directly with existing islet cells. Sernova recently announced positive preclinical data on their Cell Pouch System, a small container designed to hold islet cells under the skin, providing a protective "pancreas-like" environment, says CEO Philip Toleikis.
Note that Sernova has a pretty impressive supporter: Dr. James Shapiro, who serves as the principal investigator and was the creator of the Edmonton Protocol, which pioneered work in the field of islet cell transplantation in the late 1990s. Ironically, his former partner at the Edmonton Protocol, Jonathan Lakey, is one of the researchers at rival company Cerco Medical.
Sernova's CEO Philip Toleikis spoke with us recently about how his company's work compares to others and what we can expect from them in 2012:
DM) Let's start at the beginning: what is unique about Sernova's product?
PT) In our device, the Cell Pouch, we're allowing microvessels into the device, and then we also have the ability to locally protect the cells. A number of small companies have developed devices that can wall off the immune system, but when you do that, you eliminate the ability to integrate with the microvessels. A lot of devices in the past have shown not to be scalable to animal models or human models, because when you wall off the cells from the immune system, you're also walling off the critical microvasculatures.
When companies try to scale up, they have issues with how the body reacts. You really need that microvessel communication. The idea is that islets need to be surrounded by micro blood vessels, so that they can read the blood sugar levels and release the appropriate amount of insulin. Our particular device allows microvessels to move into the device and move in between the islets. We have proven that this can occur in animal models.
Another thing we have is local immune protection therapy. We can place cells that are immune protective, and that could potentially eliminate the need for immune rejection drugs entirely. We can prove the technology in three different models: rats, pigs and primates. We're able to meet the needs of the biology, and therefore can scale the device for use in humans.
Your principle investigator is Dr. James Shapiro, of the famous Edmonton Protocol. How did that relationship develop?
The Sernova team was introduced by Dr. David White, the chair of Sernova's Scientific Advisory Board at the International Transplantation Meeting in Vancouver in the Fall of 2010. Dr. Shapiro reviewed Sernova's preclinical data and then, based on the positive results, saw the potential of Sernova's Cell Pouch to improve the lives of people with diabetes. He then became interested in conducting Sernova's first trial as Principal Investigator. He has since reviewed our new supporting data on a regular basis and has signed a major collaboration to do advanced studies on the Cell Pouch.
How does this relate to the work done in the original Edmonton Protocol?
This is an improvement on the Edmonton Protocol. What we're using is 10-25% of the islets that were needed in the Edmonton Protocol, while getting the same efficacy. Because of the limited number of islet cells available, we're expanding the number of people who can receive the islets by using our device.
What does this Cell Pouch look like?
It's made out of polymers that have already been approved by the FDA for placement in the body long-term. The polymers are permanent and they won't break down over time. They will allow tissues and microvessels to form in between the cells. By having a permanent device, surgeons could remove it if necessary and find it through imaging techniques.
The device is subcutaneous, so it's a simple procedure to put it under the skin. By doing that, you avoid issues with transplanting islets into the portal vein of the liver. When it's placed under the skin, you can't see it above the skin. Patients can wear bathing suits or whatever they want and they won't notice there is a device.
Why is transplanting islet cells into the portal vein so problematic?
Because you're putting the islets directly into the blood stream. Because those islets are essentially sitting in the blood, inflammatory cells can go in and kill those islets. It's been shown that at least 50% of the islets transplanted into the portal vein die within a few days. Normally, islets like to be surrounded by microvessels, which are little tiny blood vessels. When islets are sitting next to the microvessels, as opposed to sitting in the blood steam, it's a healthier, more natural environment for the islets. Keeping them near the blood vessels so they can communicate is the same way that it is done naturally in the pancreas. So this is very similar to the pancreas environment.
So this device does not depend on stem cells?
For these kinds of technologies, you have to follow a regulatory path that is fairly simple. If we were to add stem cells, then it would be years away all of a sudden. By using human donors, that allows us to move into the clinic much sooner and see how it works in patients.
The islet cells in the original Edmonton Protocol eventually died. Could this happen again with the Cell Pouch?
That's the big question that we'll be asking in the clinical trials. How long will it last? What we have achieved and what we want to achieve is an environment of the natural pancreas. Islet cells last your whole life, just like brain cells. We believe they have a chance of lasting a very, very long time. In animal models, we've shown a lifespan of six months, but that was just the length of the study. Going longer is something that we have to test in humans.
The cells are called sertoli cells and they release factors which can protect cells locally from attack by the immune system. They are actually natural cells found in the body. The product is called Sertolin, which is a combination of the Cell Pouch, sertoli cells and therapeutic cells.
We have done some studies where we put pig Sertoli cells into other types of species, and those cells have locally protected the islets. We theoretically could use human cells that could be the protector cells and that would work fine. We might also be able to use porcine protector cells. We haven't developed that technology in humans yet, but we have a number of options.
Wouldn't the protector cells be recognized as foreign bodies by the immune system?
Yes, but the protector cells have the natural ability to protect themselves from an immune attack as well.
Where is Sernova going from here in 2012?
We have our technology moving forward in a number of stages. We're changing the standard of using the portal vein. We're using the latest immune-suppressant drugs, which are quite a bit improved from the previous protocols. That's going to allow us to test the Cell Pouch in patients very quickly. We'll be starting the trial in a couple of months, probably in the latter part of the first half of the year. Then we'll add the local immune protection technology.
The third tier is eventually testing the notion of placing stem cells into our device, which can be removed from the body if needed. Stem cells do have huge potential because they can exponentially expand and would allow an unlimited number of patients to be treated.
By doing this in tiers, it's allowing us to get our product into humans and start testing relatively quickly. Our ultimate goal is to treat patients with non-toxic therapy, but it will take us a bit of time to get there.
For more info on clinical trials, patients can contact Sernova by visiting their website. Thanks for the work you do, Sernova, and we're glad to see Dr. Shapiro back in the islet cell news!