Long term management of liver transplant rejection in children

Antibody immunosuppressive therapy in solid-organ transplant: Part I

Currently, a wide variety of both polyclonal and monoclonal antibodies are being routinely utilized to prevent and treat solid organ rejection. More commonly, these agents are also administered in order to delay introduction of calcineurin inhibitors, especially in patients with already compromised renal function. While these antibody therapies dramatically reduced the incidence of acute rejection episodes and improved both short and long-term graft survival, they are also associated with an increased incidence of opportunistic infections and neoplastic complications. Therefore, effective patient management must necessarily balance these risks against the potential benefits of the therapy.

Muromonab-CD3 for the successful treatment of early chronic rejection after pediatric liver transplantation: report of a case

A four-and-a-half-year-old boy underwent living-donor liver transplantation (LDLT) for progressive familial intrahepatic cholestasis. Immunosuppressive therapy was commenced with tacrolimus and methylprednisolone, despite which derangement of liver function tests (LFTs) became evident on postoperative day (POD) 7. A diagnosis of acute cellular rejection was made and steroid pulse therapy (SPT) was initiated. Although the LFTs improved transiently after SPT, they deteriorated again, and failed to respond to repeated SPT. Jaundice was prolonged and transudative ascitic fluid accumulated. Liver needle biopsies on PODs 20 and 24 confirmed severe graft damage constituting early chronic rejection. Based on the poor response to steroid therapy, coagulopathy, and protein-losing ascites, 3 mg/body weight of muromonab-CD3 was given from POD 24, increasing to 5 mg/body weight from POD 29. A rebound in LFTs appeared after the muromonab-CD3 therapy was discontinued and the LFTs normalized. The ascites and jaundice also disappeared, and the patient's general condition improved. Liver needle biopsies on POD 47 and 61 confirmed dramatic recovery from severe graft damage.

Tacrolimus: a further update of its use in the management of organ transplantation

Extensive clinical use has confirmed that tacrolimus (Prograf) is a key option for immunosuppression after transplantation. In large, prospective, randomised, multicentre trials in adults and children receiving solid organ transplants, tacrolimus was at least as effective or provided better efficacy than cyclosporin microemulsion in terms of patient and graft survival, treatment failure rates and the incidence of biopsy-proven acute and corticosteroid-resistant rejection episodes. Notably, the lower incidence of rejection episodes after renal transplantation in tacrolimus recipients was reflected in improved cost effectiveness. In bone marrow transplant (BMT) recipients, the incidence of tacrolimus grade II-IV graft-versus-host disease was significantly lower with tacrolimus than cyclosporin treatment. Efficacy was maintained in renal and liver transplant recipients after total withdrawal of corticosteroid therapy from tacrolimus-based immunosuppression, with the incidence of acute rejection episodes at up to 2 years' follow-up being similar with or without corticosteroids. Tacrolimus provided effective rescue therapy in transplant recipients with persistent acute or chronic allograft rejection or drug-related toxicity associated with cyclosporin treatment. Typically, conversion to tacrolimus reversed rejection episodes and/or improved the tolerability profile, particularly in terms of reduced hyperlipidaemia. In lung transplant recipients with obliterative bronchiolitis, conversion to tacrolimus reduced the decline in and/or improved lung function in terms of forced expiratory volume in 1 second. Tolerability issues may be a factor when choosing a calcineurin inhibitor. Cyclosporin tends to be associated with a higher incidence of significant hypertension, hyperlipidaemia, hirsutism, gingivitis and gum hyperplasia, whereas the incidence of some types of neurotoxicity, disturbances in glucose metabolism, diarrhoea, pruritus and alopecia may be higher with tacrolimus treatment. Renal function, as assessed by serum creatinine levels and glomerular filtration rates, was better in tacrolimus than cyclosporin recipients at up to 5 years' follow-up.

CONCLUSION

Recent well designed trials have consolidated the place of tacrolimus as an important choice for primary immunosuppression in solid organ transplantation and in BMT. Notably, in adults and children receiving transplants, tacrolimus-based primary immunosuppression was at least as effective or provided better efficacy than cyclosporin microemulsion treatment in terms of patient and graft survival, treatment failure and the incidence of acute and corticosteroid-resistant rejection episodes. The reduced incidence of rejection episodes in renal transplant recipients receiving tacrolimus translated into a better cost effectiveness relative to cyclosporin microemulsion treatment. The optimal immunosuppression regimen is ultimately dependent on balancing such factors as the efficacy of the individual drugs, their tolerability, potential for drug interactions and pharmacoeconomic issues.

Conversion from cyclosporin to tacrolimus in paediatric liver transplant recipients

Substitution of cyclosporin with tacrolimus should be considered for paediatric liver transplant recipients with cyclosporin-associated complications such as hypertension, gum hyperplasia, hirsutism, gynaecomastia and growth retardation, as well as recurrent or refractory acute rejection, chronic duct injury or chronic rejection. Continued experience with well tolerated drug administration and careful monitoring during drug substitution has limited drug toxicity associated with tacrolimus to a level comparable to or less than that associated with cyclosporin. Successful outcome with long term graft salvage has been reported in up to 80% of patients converted to tacrolimus because of acute rejection and 50% of patients converted because of chronic rejection. Nearly all children converted because of cyclosporin-related complications have a successful outcome. Additional benefits of conversion to tacrolimus include improvement in growth and resolution of hypertension, hirsutism and cushingoid facies. Complete corticosteroid withdrawal is possible in up to 78% of children post-conversion. Long term outcome in these patients may be optimised by conversion to tacrolimus at an early stage of acute or chronic transplant rejection in order to minimise the cumulative amount of immunosuppression. Avoidance of cyclosporin-related toxicity and minimisation of corticosteroid therapy may further improve patient compliance to drug therapy.

Daclizumab: a review of its use in the management of organ transplantation

The humanised monoclonal antibody daclizumab is an immunosuppressive agent that reduces acute rejection in solid organ transplantation. It is specific for the alpha subunit (Tac/CD25) of the interleukin (IL)-2 receptor on activated T cells and achieves immunosuppression by competitive antagonism of IL-2-induced T cell proliferation. When added to standard triple immunosuppression regimens, daclizumab significantly reduces the rate of acute rejection at 1 year in renal transplantation by 36% and there are indications that it may be effective in other solid organ transplantations. Three-year outcomes of two phase III clinical trials in renal transplantation indicate similar values for graft and patient survival between daclizumab and placebo when given in addition to triple immunosuppression; however, these pivotal trials were not designed with sufficient power to demonstrate any statistical significance. The addition of daclizumab induction shows potential in allowing calcineurin inhibitor- and corticosteroid-sparing regimens without increasing the rate of acute graft rejection or adverse effects in renal and liver transplantation. Preliminary reports indicate that daclizumab may also be a useful agent in delayed graft function and graft versus host disease (GVHD). Further investigation of its efficacy in these groups and in children is needed. Data from clinical trials show daclizumab to be well tolerated in solid organ transplantation. It does not increase the incidence of infection, including cytomegalovirus infection, when compared with placebo or no induction groups. Preliminary comparative data with muromonab CD3 indicate that daclizumab may be associated with a lower rate of infectious complications and similar or better efficacy.

CONCLUSIONS

In conclusion, daclizumab has been proven to reduce acute rejection in renal transplant recipients when given in addition to traditional baseline immunosuppression. It has shown potential to reduce acute rejection in other solid organ transplants; however, well designed, randomised studies are required to confirm this. Clinical experience from trials to date indicate that daclizumab has a tolerability profile similar to placebo with no significant effect on the incidence of infection. The relative efficacy and tolerability of daclizumab compared with other induction agents has yet to be defined. Available data suggest that daclizumab may allow the use of calcineurin inhibitor-sparing and corticosteroid-sparing regimens and may have potential in the treatment of GVHD.