Camillo Ricordi, MD, FNAI, outlines the current status of islet transplantation for patients with type 1 diabetes in the United States.
Despite the use of immunosuppressants, patients who undergo islet transplantation have more probability to survive at 20 years compared with those who undertook insulin treatment and no immunosuppression, said Camillo Ricordi, MD, FNAI, a professor and director of the Diabetes Research Institute and Cell Transplant Center at the University of Miami, Florida.
What is the current status of islet transplantation in the United States?
Practically, islet transplantation has been performed for several decades in the United States to treat the most severe cases of type 1 diabetes [T1D], including difficult-to-control metabolic control like with high hemoglobin A1C. More recently, studies have focused on patients with severe hypoglycemic episode as a consequence of the so-called hypoglycemia unawareness; that is, the inability of patients to sense a hypoglycemic crisis when they come so they're exposed more at the risk of severe hypoglycemia. But recently, we found that besides the benefits as far as normalizing hemoglobin A1C levels without the risk of severe hypoglycemia, that is something that has been achieved by islet transplantation in United States. We completed the phase 3 trial, Food and Drug Administration phase 3 trial, funded by the National Institutes of Health and included 8 centers in North America that completed successfully this trial showing the clear benefit of islet transplantation as far as achieving any abnormal hemoglobin A1C in the absence of severe hypoglycemic episodes.
More recently, actually, a few months ago, we published also a paper showing that the 20-year patient survival following an islet transplant is much higher compared to what has been published for insulin therapy in subjects with diabetes of similar age. As you know, diabetes is a disease that is associated with accelerated aging. Early in life, everything is okay, but it's like if you consume faster, your regenerative repair mechanism—because of the chronic inflammatory state that is associated with diabetes—then after age 35, or 40, you see that you have a slope of the decrease in patient survival over 60 years that have been reported in previous studies. It is like less than 60% probability of survival at 20 years if you are 43 years of age or in the age range where we perform typically an islet transplant.
While in islet transplantation, this survival was 85%, the cumulative patient survival at 20 year—which means that despite the use of antirejection drugs that have been something traditionally feared in limiting the applicability of islet transplantation, despite the use of immunosuppression—patients have more probability to survive at 20 years with an islet transplant and immunosuppression compared with insulin treatment and no immunosuppression. So this opens the way of thinking about islet transplantation as a potentially life-saving procedure, not just for subjects who have severe hypoglycemia, but for everyone, especially patients with a higher level of hemoglobin A1C that are typically associated with the faster progression to chronic complication of the disease, like hypertrophy, neuropathy, everything-opathy.