Early Results of the CellCept® Spare the Nephron Study Examine Kidney Function

Interim results from a multicenter trial investigating a novel kidney-sparing treatment protocol using CellCept® (mycophenolate mofetil) were presented at the American Transplant Congress. This and other Spare the Nephron (STN) trials in kidney and liver transplant recipients examine ways to prevent rejection without damaging kidneys.

As transplant patients are living longer, doctors are finding that older therapies such as steroids and calcineurin inhibitors (CNIs) can cause impairment of kidney function and damage to the blood vessels and filtering capacity of the kidneys.[1],[2] The STN trials are being conducted at more than 35 transplant centers in the United States and Canada and use CellCept and other immunosuppressants in combinations that reduce or eliminate the use of steroids and CNIs.

“Our goal for the Spare the Nephron trial in kidney transplant recipients is to determine the safest and most effective immunosuppressive therapy regimen that avoids the nephrotoxic effects of CNIs while preventing rejection,” said Matthew Weir, M.D., professor and director of the division of nephrology at the University of Maryland School of Medicine. “The preliminary study results are very encouraging.”

Dr. Weir reported that first-year results in kidney transplant recipients demonstrated that patients on CellCept and sirolimus maintenance therapy showed improvements in glomerular filtration rate (GFR) of their kidneys without increasing rejection rates.

A total of 208 of 305 kidney transplant patients completed 12 months of follow-up in this open-label, prospective, randomized, multicenter study. Patients initially treated with CellCept and a CNI were randomized to receive CellCept and sirolimus or to continue their current treatment regimen of CellCept and a CNI. Efficacy endpoints included the proportions of patients experiencing acute rejection, graft loss, death, and the percent change in measured GFR.

After 12 months of follow-up, investigators found acute rejection in 6.1% of patients in the CellCept and sirolimus group, compared to 7.3% of patients in the CellCept and CNI group. Graft loss was experienced by 2.0% of patients in the CellCept and sirolimus group, compared to 3.6% of patients in the CellCept and CNI group.

None of the patients in the CellCept and sirolimus group died, while one patient death was remotely related to the CellCept and CNI group. Patients in the CellCept and sirolimus group had a median 18.5% increase from baseline in GFR, compared to a median 4.4% decrease in the CellCept and CNI group. Safety outcomes were similar in both groups.

Optimizing use of immunosuppressants for achieving long-term success is the primary focus of these clinical trials. Kidney STN, liver STN and OptiCept are all studying CellCept with the goal of reducing CNI associated nephrotoxicity therapy to prolong graft and patient survival. Final results of this study, which will be available later this year, will provide more definitive conclusions about the long-term effect of these regimens on renal function.