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The Promise of Type 1 Research
May 11, 2009
Editor’s note: The research described in this post aims to halt or reverse Type 1 diabetes very early in its course and does not directly apply to people who have had the disease longer than a few months. Given that limited funding is available for any kind of diabetes research, do you think this is the right place to focus research dollars? If not, what would you like diabetes researchers to focus on? And how should Type 2 diabetes research fit in? Leave a comment below!
As a medical writer who frequently covers diabetes research, I’ve never sensed so much excitement in the air about the prospect of a significant breakthrough for Type 1 diabetes. Right now, a number of approaches are being tested very early in the course of Type 1 diabetes to see if they can slow, halt, or even reverse the destruction of the insulin-producing pancreatic beta cells by the T cells of the immune system. While none of these approaches is designed to reverse long-term Type 1 diabetes, the success of any treatment could lead to valuable knowledge that may one day lead to a cure. Here are some of the more promising ongoing clinical trials I’ve come across.
The New Kids on the Block
Many researchers believe — and I agree — that it’s important to test as many potential therapies as possible, because no one really knows which agents or combinations of agents will ultimately be most effective. The following are a couple of relatively new therapies being tested for recent-onset Type 1 diabetes.
Prochymal. A Phase II trial is currently recruiting participants to test the effects of a cell-based therapy called Prochymal. The active ingredient in Prochymal is a preparation of adult stem cells collected from the bone marrow of healthy volunteers. Researchers are studying whether, after migrating to the pancreas, these cells can halt the immune attack on the beta cells so that they can remain functional and possibly even regenerate. Participants in the trial must be 18–30 years old and have been diagnosed with Type 1 diabetes between two and 16 weeks before being screened for eligibility. They will receive three intravenous infusions of either Prochymal or a placebo (inactive agent) 30 days apart. The researchers will then compare the treatment and placebo groups using a number of measurements, including C-peptide response (a measure of pancreatic function), insulin required, HbA1c level, episodes of hypoglycemia, and blood level of certain diabetes-associated autoantibodies (proteins created during an immune-system attack on part of the body, such as the pancreatic beta cells).
START. The Phase II START study is recruiting volunteers to test the potential benefits of a drug called thymoglobulin, which traditionally has been used to prevent the rejection of transplanted organs. Thymoglobulin is thought to work in at least two ways: by eliminating destructive T cells from circulation, and by altering the way the remaining T cells work. Participants must be 12–35 years old and have been diagnosed with Type 1 diabetes no more than 12 weeks before entering the study. They will receive an escalating four-day regimen of thymoglobulin injections or four daily injections of saline solution. The treatment and placebo groups will be compared based on C-peptide response.
The two most promising trials, in my opinion, are the ones testing a class of treatments called anti-CD3 monoclonal antibodies. Both of the substances used in these studies have already been tested in humans with Type 1 diabetes and have shown promising results.
Protégé. The Protégé trial is designed to determine whether a drug called teplizumab can protect the beta cells of people with newly diagnosed Type 1 diabetes. Teplizumab is intended to destroy the T cells that are attacking pancreatic beta cells, allowing a different type of T cell — regulatory T cells — to repopulate the immune system so that it tolerates the beta cells. A study reported in the journal Diabetes in 2005 showed that giving the drug to people with recent-onset diabetes improved their beta cell function, lowered their HbA1c levels, and reduced their insulin requirements.
This Phase III trial is recruiting people 8–35 years old who have been diagnosed with diabetes no more than 12 weeks before starting treatment in the study. Participants will receive daily intravenous infusions of the drug or placebo for 14 consecutive days, which will be repeated after six months. Researchers will determine whether participants who received the drug require less insulin, have a lower HbA1c level, or have a better C-peptide response than those who received the placebo.
DEFEND-1. A trial called DEFEND-1 is testing the effects of another anti-CD3 monoclonal antibody called otelixizumab. A study reported in The New England Journal of Medicine in 2002 showed that this treatment slowed the loss of insulin production and improved blood glucose control during the first year of diabetes in the majority of patients. DEFEND-1 is recruiting people 18–35 years old who have been diagnosed with Type 1 diabetes no more than 90 days before the start of the study treatment. Participants will receive an eight-day series of otelixizumab or placebo intravenous infusions. Researchers will record the effect of the drug on C-peptide response, insulin requirements, HbA1c level, and incidence of especially high or low blood glucose levels.
Should You Volunteer?
The best motive for volunteering for a clinical trial is the altruistic one — furthering the cause of diabetes research. In addition, the potential benefits for participants who end up in the treatment group of a promising drug are obvious: diabetes that is easier to control, lower HbA1c values, and a lower risk of diabetic complications down the road. However, there are benefits even for those who end up in the placebo group — namely, excellent monitoring and diabetes care by a team of health-care providers.
The major downside to trial participation is the risk of side effects. In most cases, the potential side effects of the drug being studied are well known and well monitored. However, it is important to find out about the risks of the drug you may be taking.
To search for clinical trials, log on to www.clinicaltrials.gov. Meanwhile, the Juvenile Diabetes Research Foundation is working to design a user-friendly registry that will make it easier to find clinical trials that you might qualify for.
Robert S. Dinsmoor is a contributing editor to Diabetes Self-Management magazine and a medical writer based in South Hamilton, Massachusetts.
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