Type 1 diabetes, also known as insulin-dependent diabetes, is a chronic disease in which the
pancreas produces insufficient insulin to properly regulate blood sugar levels.
Hypoglycemia, low blood sugar, and hyperglycemia, high blood sugar, can lead to significant
complications in people with type 1 diabetes. Intensive insulin therapy has been shown to
reduce the risk of chronic complications in people who achieve near normalization of
glycemia. However, this therapy is labor intensive, difficult to implement, and associated
with an increased frequency of severe hypoglycemia. Transplantation of islets from a healthy
pancreas has been successful in restoring normal blood sugar levels and has led to initial
insulin independence in people with type 1 diabetes. Rejection of these islets by the
recipient's immune system, however, makes the treatment ineffective within a couple of
years. Immunosuppressant drugs may be an effective way to maintain islet function
post-transplant. The purpose of this study is to assess the safety and efficacy of an
immunosuppressive regimen that includes DSG on post-transplant islet function in people with
type 1 diabetes who have not responded to intensive insulin therapy. The study will also
seek to improve the understanding of determinants of success and failure of islet
transplants for type 1 diabetes.
Following screening procedures and 2 days prior to islet transplant, participants will be
randomly assigned to either this Phase 2 trial or a multicenter Phase 3 trial. Participants
in this study will receive up to three separate islet transplants. They will begin receiving
antithymocyte globulin (ATG) and sirolimus 2 days prior to the first islet transplant. ATG
will continue to be given until Day 2 post-transplant. Participants will continue taking
sirolimus for the duration of the study. On the day of transplant, participants will receive
DSG and etanercept, in addition to ATG and sirolimus. The DSG infusion will be administered
over 3 hours and will immediately precede the islet transplant. Participants will continue
receiving daily 3-hour infusions of DSG through Day 6 post-transplant. Etanercept will also
be administered on Days 3, 7, and 10 post-transplant. Tacrolimus will be administered on Day
1 post-transplant and continued throughout the study.
Transplantations will involve an inpatient hospital stay and infusion of islets into a
branch of the portal vein. Participants who do not achieve or maintain insulin independence
by Day 75 post-transplant will be considered for a second islet transplant. Participants who
remain dependent on insulin for longer than 1 month after the second transplant and who show
partial graft function will be considered for a third transplant. Daclizumab or basiliximab
will be used in place of ATG for the second and third transplants, if they are necessary.
Participants who do not meet the criteria for a subsequent transplant and do not have a
functioning graft will enter a reduced follow-up period.
There will be up to 21 study visits following each transplant. A physical exam, review of
adverse events, blood collection, urine tests, and measures of immunosuppression levels will
occur at most visits. An abdominal ultrasound and glomerular filtration rate testing will
occur at some study visits. Participants will also self-test their glucose levels at least
five times per day throughout the study. A 12-month follow-up period will take place after
the participant's last transplant.