Therapeutic drug monitoring for everolimus in kidney transplantation using 12-month exposure, efficacy, and safety data

Improving outcomes in heart transplantation: the potential of proliferation signal inhibitors

Graft failure and mortality among heart transplant recipients remains higher than in populations receiving renal transplants. A major cause of graft loss is cardiac allograft vasculopathy (CAV), a condition characterized by diffuse thickening of coronary blood vessels. CAV often progresses silently, with major cardiac events (eg, ventricular arrhythmia) being the first presentation. Better diagnosis and monitoring of CAV is now possible with intravascular ultrasonography, a sensitive technique for measuring intimal thickness. To date, immunosuppressants have shown little efficacy for preventing CAV. However, a new class of agents, proliferation signal inhibitors (sirolimus and everolimus), have shown considerable efficacy in this regard and for preventing rejection. In an open-label trial, sirolimus therapy was associated with less intimal and medial proliferation than azathioprine. More robust evidence is available from a larger-scale, double-blind trial involving everolimus. At 12-month follow-up the incidence of CAV was significantly lower in patients receiving everolimus (35.7% and 30.4% for everolimus 1.5 and 3.0 mg/d vs 52.8% for azathioprine; P < .05). Sirolimus and everolimus were also associated with a lower rate of cytomegalovirus infection. As with other immunosuppressants, these agents are associated with adverse events (eg, hyperlipidemia), but they can be managed. Coadministration with calcineurin inhibitors (CNIs) can exacerbate CNI-related nephrotoxicity, but evidence suggests that everolimus administered with reduced-exposure cyclosporine in the maintenance phase preserves renal function without loss of immunosuppressive efficacy. Reduced CNI dosing in de novo patients is also a potential future benefit. Proliferation signal inhibitors have considerable potential for improving outcomes in heart transplantation.

Introducing Everolimus (Certican) in Organ Transplantation: An Overview of Preclinical and Early Clinical Developments

Everolimus (Certican) is a novel proliferation signal inhibitor with potent immunosuppressant effects that has been shown to prevent and reverse acute rejection in preclinical models of kidney, heart, and lung transplantation. These effects have been confirmed by clinical studies in which everolimus demonstrated comparable efficacy to azathioprine and mycophenolate mofetil in heart and renal transplantation, respectively, when combined with full-dose cyclosporine (CsA; Neoral). Experimental studies have also shown that everolimus inhibits smooth muscle cell proliferation and prevents neointimal thickening and transplant arteriosclerosis. Importantly, everolimus was shown to significantly reduce both the incidence and severity of cardiac allograft vasculopathy in recipients of heart transplants, which if confirmed in long-term studies, could provide a major advantage in these patients. Use of everolimus was also associated with lower rates of cytomegalovirus infection in both indications. Studies in which everolimus was combined with reduced-exposure CsA have demonstrated significantly improved renal function when compared with full-dose regimens, with no loss of efficacy. The results of preclinical and clinical studies with everolimus thus indicate that this novel proliferation signal inhibitor will be an important addition to the armamentarium by enhancing graft survival and minimizing toxicity.

Concentration-Controlled Everolimus (Certican): Combination with Reduced Dose Calcineurin Inhibitors

The calcineurin inhibitors (CNIs) have been the cornerstone of immunosuppressive therapy in recent years, though their association with dose-related nephrotoxicity is a major factor in the development of chronic allograft nephropathy in kidney transplant recipients. The novel proliferation signal inhibitor everolimus (Certican) has a mode of action distinct and complementary to the CNIs, which is thought to underlie the demonstrated synergy between everolimus and cyclosporine (CsA) in preclinical models. This finding suggests that everolimus may allow for CNI dose reduction, enabling nephrotoxicity to be minimized without compromising efficacy. Two prospective, multicenter, randomized studies have investigated the efficacy and safety of everolimus (1.5 or 3.0 mg/day) combined with reduced-exposure CsA (Neoral) in de novo renal transplant patients. In these studies, the everolimus trough level was maintained at > or =3 ng/ml with therapeutic drug monitoring and the CsA dose optimized with C(2) monitoring. The incidence of efficacy failure with this regimen was shown to be comparable with that provided by regimens employing full-dose CNIs, but with good renal function. Furthermore, everolimus (trough levels 3-8 ng/ml) plus reduced-exposure CsA was associated with a marked reduction in acute rejection compared with regimens using fixed-dose everolimus or mycophenolate mofetil plus full-dose CsA. At 12 months follow-up, CsA trough level was 57% lower in these trials than in previous trials in which patients received full-dose CsA. This suggests that concentration-controlled everolimus can be successfully combined with optimized administration of CsA and that this regimen may maximize immunosuppression, whilst preserving renal function.