Diabecell Therapy for Type 1 Diabetes
Once again, at the suggestions of Allie Beatty and Ann Bartlett, I have checked out one of the newer technologies in early stages of development, Diabecell. According to LCT (living cell technologies) Diabecell is a "porcine (pig), insulin producing cell product for the treatment of type 1 diabetes mellitus. The islet cells are self-regulating and efficiently secrete insulin in the patient's body." The main difference between the Edmonton Protocol developed by Dr. Shapiro of Canada requiring radiographic imaging and injection of human islet cells in the portal vein is that these islet cells are derived from piglets and are encapsulated and can be administered by an injection into the abdominal cavity (peritoneum) by laparoscopy under local anesthesia. Encapsulation of the cells is critical and the reason why no anti-rejection or immunosuppressant drugs are necessary. The company first entered clinical trials for Diabecell in 2007.
According to Living Cell Technologies, clinical trials were conducted in Russia to test the safety and efficacy of Diabecell. In this trial, 10 patients received the implanted cells in differing doses. The doses are defined as islet equivalents (IEQs) ranging from 5,000-15,000 IEQs/kg of body weight. A second transplant was required six months later. In May 2009, LCT reported preliminary data showing sustained long-term clinical benefits with the Diabecell transplants with no remarkable adverse events. In New Zealand, based on LCT's web site, Phase 2 trials are underway at Middlemore Hospital in Auckland. In this trial, eight patients will receive the porcine implants. Of the eight patients, four will receive double the initial dose received in Russia followed by four patients who will receive triple the dose. Essentially these trials are trying to determine the IEQs required to maximize glycemic control safely and over the long-term.
Review of published abstracts provided by Living Cell Technologies has demonstrated success in reducing insulin dosages and several patients became insulin-independent for several months. In one study, the insulin dose was reduced by 30 percent after 12 weeks. The insulin dose returned to pre-transplant levels after week 49. Improvement of hb A1c was noted as well, with a pre-transplant level of 9.3 percent to 7.8 percent at 14 months post-transplant. Even more significant was that urine c-peptide (a marker of insulin) remained detectable for 11 months. In terms of safety, a study published in 2004 revealed that after a nine-year follow-up of 18 human patients receiving pig islet cell transplants, no evidence of viral infection was found. This information is important because there is always the risk that the pig's tissues may harbor infectious agents. Another study developed techniques to monitor pig herds and tissues prior to their use in transplantation. And lastly, due to these concerns about the virological risk of transplantation, a study conducted in 2000, revealed no evidence of infection with porcine retrovirus in recipients of encapsulated islet transplants.
There have been no studies conducted in the United States and to my knowledge the FDA has not approved Diabecell.
Based on a communication from Ann Bartlett, Allie Beatty has actually chatted with one of the scientists at Living Cells Technologies about Diabecell in terms of expense and the number of pigs required to harvest the islet cells. Per Allie, ten porcine pancreases are required for every transplant with the cost of each pig of about $10,000. To maintain a bottom line for the company, LCT must charge approximately $100,000 per procedure. I am not surprised about the expense, as it is crucial that these pigs be safe and bred in sterile conditions to avoid transmission of porcine viruses to humans.
What are the benefits and disadvantages of this new technology?
- The potential ability to become insulin independent without hypoglycemia.
- Encapsulation of the porcine islet cells and thus the lack of requirement of immunosuppressive drug therapy.
- Due to the lack of immunosuppressive therapy, the potential risk of infection and cancer is markedly diminished.
- No human cadaveric pancreases required.
- The presence of an animal source of insulin that (in theory) can be based on supply and demand.
- The demonstrated safety profile (so far).
- Lack of injection of islet cells in the portal vein (risky) per the Edmonton Protocol. Islet cells injected into the peritoneum by laparoscopy.
- Need for expensive pigs to harvest the islet cells.
- Despite a period of insulin-independence, insulin requirements appear to return.
- Probable frequent injections of encapsulated porcine islet cells to maintain glycemic control.
- Continued need for monitoring due to safety concerns.
- Need for FDA approval in the United States
- Studies have only documented results in a few type 1 diabetes subjects.
- Unknown future.
I will keep you posted.