Long-term maintenance therapy with calcineurin inhibitors: an update

One-Year Multicenter Double-Blind Randomized Clinical Trial on the Efficacy and Safety of Generic Cyclosporine (Iminoral) in De Novo Kidney Transplant Recipients

OBJECTIVES

Iminoral is the generic microemulsion of cyclosporine. We performed a randomized double-blind multicenter trial to evaluate its efficacy and safety compared with the innovator medication Neoral for preventing acute rejection episodes in adult patients during the first year after renal transplant.

MATERIALS AND METHODS

We used 221 de novo renal transplant recipients from 6 transplant centers in Iran enrolled between April 2008, and January 2010. They were randomized to receive either Iminoral or Neoral as the calcineurin inhibitor component of the immunosuppressive regimen in addition to mycophenolate mofetil and oral corticosteroids. They were followed-up for 1 year. The primary endpoint was the rate of acute allograft rejection. Secondary endpoints consisted of 1-year graft survival rates, daily dosages of cyclosporine, trough and C2 cyclosporine blood level, serum creatinine levels, patient death rates, discontinuing the study drug, tolerability, and adverse events.

RESULTS

The risk of acute rejection episode during the first month after transplant was 9% for Iminoral and 10% for Neoral; these declined to 4% and 2% during next 11 months. One-year graft survival rate was 0.86 for both groups. Renal function stabilized during the first month. Declination of the creatinine levels was similar between the 2 groups and reached a stable value of 114.9 μmol/L five months after the transplant. The frequency of clinical complications was similar between the groups.

CONCLUSIONS

Iminoral is safe and effective when used in de novo kidney transplant patients as an immunosuppressive medication.

KEY WORDS

Graft rejection, Iran, Calcineurin inhibitors.

Genomic-derived markers for early detection of calcineurin inhibitor immunosuppressant-mediated nephrotoxicity

Calcineurin inhibitor (CI) therapy has been associated with chronic nephrotoxicity, which limits its long-term utility for suppression of allograft rejection. In order to understand the mechanisms of the toxicity, we analyzed gene expression changes that underlie the development of CI immunosuppressant-mediated nephrotoxicity in male Sprague-Dawley rats dosed daily with cyclosporine (CsA; 2.5 or 25 mg/kg/day), FK506 (0.6 or 6 mg/kg/day), or rapamycin (1 or 10 mg/kg/day) for 1, 7, 14, or 28 days. A significant increase in blood urea nitrogen was observed in animals treated with CsA (high) or FK506 (high) for 14 and 28 days. Histopathological examination revealed tubular basophilia and mineralization in animals given CsA (high) or FK506 (low and high). We identified a group of genes whose expression in rat kidney is correlated with CI-induced kidney injury. Among these genes are two genes, Slc12a3 and kidney-specific Wnk1 (KS-Wnk1), that are known to be involved in sodium transport in the distal nephrons and could potentially be involved in the mechanism of CI-induced nephrotoxicity. The downregulation of NCC (the Na-Cl cotransporter coded by Slc12a3) in rat kidney following CI treatment was confirmed by immunohistochemical staining, and the downregulation of KS-Wnk1 was confirmed by quantitative real-time-polymerase chain reaction (qRT-PCR). We hypothesize that decreased expression of Slc12a3 and KS-Wnk1 could alter the sodium chloride reabsorption in the distal tubules and contribute to the prolonged activation of the renin-angiotensin system, a demonstrated contributor to the development of CI-induced nephrotoxicity in both animal models and clinical settings. Therefore, if validated as biomarkers in humans, SLC12A3 and KS-WNK1 could potentially be useful in the early detection and reduction of CI-related nephrotoxicity in immunosuppressed transplant patients when monitoring the health of kidney xenographs in clinical practice.