Immunosuppressive agents in clinical trials in transplantation

Rapamycin in patients with chronic renal allograft dysfunction

PURPOSE

Nephrotoxicity of calcineurin inhibitors (CNI) complicates the management of chronic renal allograft dysfunction. Rapamycin is a promising immunosuppressive agent free of nephrotoxicity. The effect of conversion from CNI to rapamycin in recipients with chronic allograft dysfunction is still unclear. We investigated the effect of rapamycin in patients with chronic allograft dysfunction.

METHODS

We conducted a prospective study on kidney transplant recipients with chronic allograft dysfunction. The patients were under classic CNI, mycophenolate mofetil, and prednisolone triple therapy. They had progressive deterioration of the allograft function. They were converted from CNI to rapamycin directly and observed for 6 months. The CNI serum levels before the conversion were within recommended range. Allograft function, clinical features and adverse effects were evaluated before and after the rapamycin conversion.

RESULTS

A total of 16 patients were enrolled. Six of them (37.5%) failed to have a smooth conversion because of deterioration of allograft function and intractable adverse effects. Ten patients (62.5%) went through the 6-month observation period with improved graft function. The average reduction of serum creatinine was 27.7% (p < 0.001) in successful conversion. There were no significant differences on age, gender, lipid profile, sugar control, and rapamycin levels between successful and failed conversion. Anemia and diastolic blood pressure were significantly improved after successful conversion. The failed patients had a longer transplantation period (6.1 +/- 4.1 vs. 11.2 +/- 3.4 yr, p < 0.05). Two of them (12.5%) developed bacteria pneumonia. Self-limited diarrhea developed in three patients (18.8%).

CONCLUSION

We suggested that conversion from CNI to rapamycin was beneficial in some kidney transplant recipients with chronic allograft dysfunction.

Pharmacokinetic advantages of two-hour post-dose cyclosporin a level for the therapeutic drug monitoring in stable Chinese kidney transplant recipients

BACKGROUND

Recent studies in Caucasian patients show that 2-hour post-dose cyclosporin A level (C2) monitoring has excellent correlation with the actual drug exposure and risk of rejection. However, the reliability of using C2 in stable Chinese renal transplant patients is unknown.

METHODS

Forty-nine stable Chinese renal transplant patients receiving microemulsion cyclosporin A (Neoral) as part of their immunosuppressive therapy were recruited. Area under the time-concentration curve (AUC) was determined from whole blood cyclosporin A level taken at 0, 1, 2, 4 and 6 h post-dose at time 0 month. Cyclosporin A levels were repeated at 0, 1 and 2 h post-dose at 1 and 2 months later to determine the intra-individual variation at these specific time points.

RESULTS

The average duration of transplantation was 77 +/- 42 months, with average daily cyclosporin dosage of 200 +/- 43 mg in two divided doses. AUC has excellent correlations with cyclosporin A level at 1 h (C1) and 2 h (C2) (r = 0.81 and 0.82 respectively, p < 0.001 for both). The correlation between AUC and trough cyclosporin A level (C0) was statistically significant but only modest (r = 0.52, p < 0.001). On the other hand, the intra-individual coefficient of variation (CVw) of C1 was significantly larger than that of C2 (34.4 +/- 24.2 vs. 15.9 +/- 8.3%, p < 0.0001).

CONCLUSION

We conclude that C2 level has favorable pharmacokinetic properties for therapeutic drug monitoring in stable Chinese transplant recipients. Both C1 and C2 have excellent correlation with AUC, but the intra-individual variability of C2 is much lower than that of C1.

The outcome of kidney transplants with multiple renal arteries

Background

The use of grafts with multiple renal arteries has been considered a relative contraindication because of the increased incidence of vascular and urologic complications The aim of this study is to determine whether the kidney grafts with multiple arteries have any adverse effect upon post-transplant graft and patient survival.

Methods

We reviewed the records of 225 adult kidney transplants done consecutively at our institution. Twenty-nine patients (12.8%) had grafts with multiple renal arteries. We analyzed the incidence of post-transplant hypertension and vascular complications, mean creatinine levels, patient and graft survival. In 17 cases reconstruction was done as conjoined anastomosis between two arteries of equal size, and in 6 cases as end-to-side anastomosis of smaller arteries to larger arteries. Multiple anastomoses were performed in 6 cases.

Results

In one patient postoperative bleeding occurred. Mean systolic blood pressures, creatinine levels at first year and last follow-up and complication rates were all in acceptable ranges. There was no significant difference in graft and patient survival between multiple and single renal artery allografts.

Conclusion

Although the kidney grafts with multiple renal arteries have been considered a relative contraindication because of the increased risk of complications, in our study allografts with multiple arteries were used successfully in kidney transplantation.

The challenge of rejection and cardiac allograft vasculopathy

Since the first human heart transplantation was performed in 1967, the field of heart transplantation has advanced to the point where survival and acceptable quality of life are commonplace. Despite remarkable progress in the clinical management of rejection, rejection continues to limit survival and quality of life in the heart transplant population. This review will discuss the biologic processes involved in hyperacute rejection, acute rejection, and humoral (vascular) rejection. The development of endomyocardial biopsy techniques represented a significant advancement in the diagnosis of cardiac rejection, and endomyocardial biopsy remains the 'gold standard' in the diagnosis of cellular rejection. To date, no noninvasive parameters will diagnose rejection with adequate sensitivity and specificity. Biopsy frequency and immunosuppressive therapies may be tailored to the risk of rejection. Immunosuppression for cardiac transplantation can be divided into three major phases: 1) perioperative immunosuppression; 2) maintenance immunosuppression, and; 3) treatment of rejection. The strategy for treating transplant rejection should be influenced by several variables: 1) Histologic grade of rejection; 2) Evidence of hemodynamic compromise by ejection fraction or right heart catheterization; 3) Severity of previous rejection episodes and types of immunosuppressives used; and 4) Risk factors for rejection, including time after transplantation. Future rejection therapy will involve more sophisticated attempts to alter host responses toward the donor organ in a more specific and selective way. Despite considerable advances in the care of the heart transplant recipient, long-term survival is limited by cardiac allograft vasculopathy. The final section of this chapter will review the pathology, immunopathology, nonimmunologic risk factors, diagnosis, prevention and treatment of allograft vasculopathy.

Renal transplantation in infants and children

Renal transplantation is the treatment of choice in children with end stage renal disease. Advances in organ retrieval and preservation, improved surgical techniques and postsurgical care, newer immunosuppressive drugs and prevention and treatment of infections have significantly improved survival of the renal allograft. The absolute requirements for a transplant are compatible blood group and a negative cytotoxic crossmatch. HLA identical grafts have a longer half-life than those that are less well matched. The immunosuppressive drugs most often used are cyclosporin A (or tacrolimus), azathioprine (or mycophenolate mofetil) and prednisone. Complications following transplantation include episodes of acute rejection, serious bacterial and viral infections, hypertension and recurrence of primary disease in the allograft. Each centre must have standard protocols for pre-transplant evaluation, and monitoring during surgery and in the post-operative period. Socio-economic factors should be evaluated before offering renal transplantation to children in developing countries.

The use of over-the-counter medications by transplant recipients: a guideline

Over-the-counter medications are becoming increasingly available to the general public. One of the issues facing clinicians working with transplant recipients is how to advise patients regarding management of symptoms associated with common ailments. Minimal literature is available to assist the transplant coordinators in this process. This article describes the usual immunosuppressants prescribed for transplant recipients and the over-the-counter medications used to manage these symptoms, and provides recommendations for over-the-counter medications with the least side effects.

Clinical outcome of renal transplantation. Factors influencing patient and graft survival

The 1-year graft survival rate for primary cadaver kidney transplants performed in the US during the past 9 years was 82%, and it was 94% when living donor kidneys were transplanted. After the first year, however, half of the surviving cadaveric grafts will fail within 8 years. This late rate has not changed substantially in the past 20 years. This article describes some of the factors that affect long-term graft and patient survival rates.