The drug tacrolimus (also known as FK506) can halt or reverse unmanageable rejection of transplanted kidneys in three out of four cases says a report from 13 of the country's leading transplant centers.
Despite tremendous progress in regulating the immune system, stubborn or "refractory" rejection-an unrelenting immune system assault against the transplanted organ-remains one of the principal problems of organ transplantation. This is the first multi-center trial to demonstrate such encouraging results for persistent kidney rejection.
The study, which involved 73 patients who entered the trial between September, 1993, and May, 1994, is reported in the September 15, 1996, issue of Transplantation.
Tacrolimus rescue therapy, concluded the authors, provides prompt, effective reversal of refractory kidney rejection, good long-term kidney function, a low incidence of repeat rejection, and an acceptable safety profile.
"Our consistent success in reversing the worst-of-the-worst cases means that tacrolimus has become our preferred treatment for patients who experience refractory rejection following a kidney transplant," said the paper's lead author transplant surgeon E. Steve Woodle, M.D., from the University of Chicago Medical Center.
"Since uncontrolled rejection remains a primary cause of organ loss, this is a significant advance for our patients," he added.
Although about half of kidney transplant patients will experience at least one episode of rejection, a temporary boost in their medications-increased doses of corticosteroids or anti-lymphocyte antibodies-can usually bring the rejection under control.
About 10 to 15 percent of patients, however, experience uncontrollable or repeated bouts of rejection. These patients require additional therapy; however, the side effects of repeated courses of standard antirejection therapies-increased risk for infections or for a form of lymphoma associated with these drugs-are excessive.
Tacrolimus, however, reversed rejection in 75 percent of patients with repeated or uncontrollable rejection. It halted kidney damage in another 11 percent. Only 11 percent of patients given tacrolimus experienced progressive deterioration of the transplanted kidney.
These results indicate that overall, tacrolimus therapy may reduce the 10 to 15 percent of kidneys that are lost to repeated or uncontrollable rejection to only two to four percent, a significant advance.
This multi-center report confirms an earlier kidney study from the University of Pittsburgh that found nearly identical results. Previous studies in liver transplant recipients have also demonstrated a similar results.
Transplant centers participating in the study include the University of Chicago, the University of Alabama at Birmingham, Johns Hopkins, Univ. of Calif. at San Francisco, Mount Sinai Hospital (NY), Univ. of Calif. at Los Angeles, New England Deaconess, New England Medical Center, St. Vincent's Hospital, Mayo Clinic, Univ. of Wisconsin, Massachusetts General Hospital, and Emory University.