Minimization of calcineurin inhibitors: a review of de-novo strategies and conversion algorithms:

Decreased Acute Rejection and Improved Renal Allograft Survival Using Sirolimus and Low-Dose Calcineurin Inhibitors without Induction Therapy

Background

Chronic nephrotoxicity of calcineurin inhibitors (CNIs) causes irreversible renal dysfunction and shortens renal transplant survival. We conducted a retrospective cohort study to test a hypothesis that de novo CNI minimization combined with sirolimus (SRL) improves graft survival in renal transplant patients without antibody induction therapy.

Methods

Between October 2000 and August 2007, we performed 100 cases of renal transplantation with de novo CNI (either cyclosporine or tacrolimus) minimization combined with sirolimus (SRL group). The initial target trough levels were 100–200 ng/ml for cyclosporine (CsA) and 4–8 ng/mL for tacrolimus (TAC). SRL was given at a loading dose of 6 mg plus 2 mg/day for maintenance. The results for the SRL group were compared to those of 104 transplant recipients given standard CNI- (CsA- or TAC-) based immunosuppressive regimens including mycophenolate mofetil (MMF group) during the same period.

Results

The 1-year rejection-free survival (94.8%) and 5-year graft survival (87.7%) rates of the SRL group were significantly better than those of the MMF group (85.5% and 75.2%, respectively). On univariate analyses, 6-month estimated glomerular filtration rate (eGFR), acute rejection and SRL therapy had a significant impact on graft survival, and SRL therapy and tacrolimus therapy had a significant impact on rejection-free survival. Multivariate analyses identified 6-month eGFR as the only prognostic factor for graft survival. Acute rejection and SRL therapy were significant for post-transplant renal function.

Conclusions

De novo CNI minimization combined with SRL could decrease acute rejection and improve renal function and graft survival after renal transplantation without the use of antibody induction therapy.

Calcineurin-inhibitor pain syndrome

BACKGROUND

There has been increased recognition of calcineurin, a phosphoprotein serine/threonine phosphatase enzyme, in the regulation of many physiologic systems. Calcineurin mediates activation of lymphocytes, which play a role in immune response. Widely distributed in the central nervous system, calcinuerin also plays an important role in sensory neural function, via its role in the regulation of newly discovered 2-pore potassium channels, which greatly influence neuronal resting membrane potentials. Calcinuerin inhibition is the mechanism of action of immunomodulatory drugs such as cyclosporine and tacrolimus, which are widely used in transplantation medicine to prevent rejection. While important for immunosuppression, the use of calcineurin inhibitors has been associated with the development of a new pain syndrome called the calcineurin pain syndrome, which appears to be an untoward complication of the interruption of the physiologic function of calcineurin.

METHODS

This is a narrative review focusing on the epidemiology, pathophysiology, characterization of a newly recognized pain syndrome associated with the use of calcineurin inhibitors.

RESULTS

The use of immunosuppressants however is associated with several well-known toxicities to which the calcineurin pain syndrome can be added. The development of this syndrome most likely involves altered nociceptive processing due to the effect of calcineurin inhibition on neuronal firing, as well as effects of calcineurin on vascular tone. The most striking aspect of the treatment of this syndrome is the response to calcium channel blockers, which suggest that the effects of calcineurin inhibition on vascular tone play an important role in the development of the calcineurin pain syndrome.

CONCLUSION

The calcineurin syndrome is a newly recognized complication associated with the use of calcineurin inhibitors. There is no standard therapy at this time but anecdotal reports suggest the effectiveness of calcium channel blockers.

Long-term outcome of very early cyclosporine minimization and de novo everolimus therapy in kidney transplant recipients: a pharmacokinetic guided approach

BACKGROUND

Cyclosporine (CsA) nephrotoxicity is an important cause of chronic allograft dysfunction. Clinical information concerning the impact of very early CsA dose reduction in kidney transplant recipients is limited. We have examined the long-term outcomes of very early CsA dose reduction. This is synchronized with de novo everolimus and steroid therapy.

METHODS

We enrolled 10 de novo kidney transplant recipients to receive CsA (target C(0) 250-350 ng/mL) and prednisolone as initial therapy. CsA dosage was reduced by 50% at posttransplant day 7. Everolimus (target trough level, 3-8 ng/mL) was concomitantly started at the day of CsA reduction. Full pharmacokinetic studies of everolimus and CsA were studied at the period of 4-8 weeks after CsA reduction. CsA was then gradually reduced to maintain a trough level of 50-100 ng/mL and/or C(max) <600 ng/mL.

RESULTS

The mean follow-up was 51.2 ± 3.45 months. The nadir serum creatinine was 1.03 ± 0.33 mg/dL. The mean initial estimated glomerular filtration rate (eGFR) was 97.97 ± 23.36 mL/min. The mean initial trough everolimus was 5.2 ± 1.5 ng/mL. The eGFR at 1 year, 3 years, and last follow-up was 82 ± 25, 80 ± 21, and 80 ± 25 mL/min, respectively. Patient and graft survival was 100%.

CONCLUSION

Very early CsA dose reduction synchronized with de novo everolimus therapy was associated with good long-term patient and graft survival in kidney transplant recipients. This intervention can lead to 75% CsA minimization and is associated with very good GFR by the modification of Diet in Renal Disease Formula at year 4.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.