Mayo Clinic Research Shows Reduced Rejection Rates After Pancreas Transplants

Thursday, December 20, 2001

ROCHESTER, MINN. — Mayo Clinic transplant specialists have identified a new treatment approach to help reduce the risk of complications for patients with diabetes after a pancreas transplant.

The results, published in the December 2001 issue of Transplantation, compared three immunosuppressant medications used in combination with aggressive identification of tissue rejection.

In the first six months after transplant surgery, the group of patients given Thymoglobulin® showed a 7.7 percent rejection rate, compared to 50 percent rejection rates for the patients who took the medications daclizumab and OKT3.

The latter two drugs are typically used following pancreas transplant. The efficacy of Thymoglobulin®, an anti-thymocyte rabbit immunoglobulin, approved by the Food and Drug Administration in 1998 for kidney transplants, wasn't known for pancreas transplants.

The anti-thymocyte immunoglobulin is made up of a variety of antibodies that recognize key receptors on T-cells — cells responsible for attacking and rejecting a foreign substance in the body. The antibodies can inactivate and kill these T-cells, reversing the rejection process.

For each patient, a Mayo Clinic transplant specialist performed biopsies three weeks and three months after the transplant to determine if there were signs of tissue rejection.

"This is an aggressive approach to identifying and managing rejection," says Mark Stegall, M.D., a Mayo Clinic kidney and pancreas transplant surgeon. "We found the biopsies identified rejection before the patient showed any symptoms."

Typically, 20 to 60 percent of transplant recipients will experience an acute rejection episode, most often in the first six months following the transplant. The result can be fever, tissue destruction and the failure of the transplanted organ.

Once identified, rejection episodes often can be treated, reducing the risk of transplant failure.

This study included 29 patients who had pancreas transplants at Mayo Clinic from 1998 to 2000. The one-year transplant success rate was 91.7 percent in the group that took the anti-thymocyte immunoglobulin and 89.3 percent in all three groups. The transplant failed in one person in the study.

"Even though this is a small group, this study showed that anti-thymocyte rabbit immunoglobulin, along with surveillance biopsies, do improve the success rate for pancreas transplants," says Dr. Stegall.

Pancreas transplants have been done for nearly 40 years — but they are usually done in combination with kidney transplants for patients with complications from diabetes. Rejection rates for pancreas-only transplants are higher than those for pancreas-kidney transplants or for kidney transplants alone.

But for some patients, a pancreas-alone transplant may be the best treatment option. Patients in this group can include:

*Those who have had a living-donor kidney transplant previously and now need a new pancreas to control the diabetes. *Those with diabetes who don't have kidney problems but could benefit from a pancreas transplant to prevent complications from diabetes.

After a successful pancreas transplant, many people with diabetes don't need to use insulin anymore or take frequent blood-sugar measurements. They're also no longer at risk of soaring or dropping blood sugar levels and the danger that brings.

Mayo Clinic has the third largest pancreas-only transplant program in the country. The Mayo Clinic Transplant Center performs more than 50 pancreas-only transplants every year.

Contact: Chris Gade 507-284-5005 (days) 507-284-2511 (evenings) e-mail: newsbureau@mayo.edu

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