A new drug is showing promise for keeping kidney transplants viable while eliminating some of the side effects of other immunosuppressive drugs.
One of the biggest challenges in organ transplantation is "rejection," caused when the body's immune system attacks the new organ. Currently, kidney transplant recipients take cyclosporine, an immunosuppressive drug that lowers the body's immune response and protects the kidney from attack. However, since the drug affects the whole immune system, it leaves the patient susceptible to infections. And after taking the drug long-term, patients often suffer from high blood pressure, high cholesterol and even damage to their new kidney.
But now an early study shows that a new drug, belatacept, may be more specific in its action, potentially helping to prolong life after kidney transplant.
"[Belatacept] is among the most important new classes of immunosuppressive drugs to be evaluated since cyclosporine was introduced more than 20 years ago," said Dr. Christian P. Larsen, director of the Emory Transplant Center at Emory University School of Medicine in Atlanta, in a statement.
Doctors think that belatacept works differently than other immunosuppressant drugs in that it prevents the immune system from attacking the new kidney without lowering the entire immune response. This should allow the body to still be able to effectively fight infections, preventing many of dangerous side effects of cyclosporine.
The early trial of belatacept, which was published on August 25 in The New England Journal of Medicine, included 218 patients who had end-stage renal disease and received a new kidney. Patients were given either cyclosporine, a high dose of belatacept or low dose of belatacept to prevent organ rejection. After six months, the rate of kidney rejection was about 7 percent for all groups. However, after a year, kidney function was found to be significantly higher in those patients receiving either regimen of belatacept. The groups taking belatacept were also about 20 percent less likely to need medication to control their cholesterol or blood pressure.
"The results of this study of the safety and effectiveness of belatacept were as good as we could hope for from the first trial of this new class of drugs," said Larsen.
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But other experts warn about missing some details of the new study. While the rates of infections were similar among the three test groups, three cases of post-transplantation lymphoproliferative disorder (PTLD) were reported in the groups taking belatacept. PTLD is a potentially fatal condition caused by a viral infection that normally affects only 1 percent of patients. This relatively high rate of the disorder indicates that belatacept may target more than the kidney in its immunosuppressive actions.
"We will need much more experience with belatacept before recommending it as a routine replacement for cyclosporine," warned the editors of the journal, Drs. Julie Ingelfinger and Robert Schwartz, in an editorial accompanying the study.
