Basiliximab plus low-dose cyclosporin vs. OKT3 for induction immunosuppression following renal transplantation

Challenges and opportunities in targeting the CD28/CTLA-4 pathway in transplantation and autoimmunity

INTRODUCTION

T cell activation is a complex process that requires multiple cell signaling pathways, including a primary recognition signal and additional costimulatory signals. One of the best-characterized costimulatory pathways includes the Ig superfamily members CD28 and CTLA-4 and their ligands CD80 and CD86. Areas covered: This review discusses past, current and future biological therapies that have been utilized to block the CD28/CTLA-4 cosignaling pathway in the settings of autoimmunity and transplantation, as well the challenges facing successful implementation of these therapies. Expert opinion: The development of CD28 blockers Abatacept and Belatacept provided a more targeted therapy approach for transplant rejection and autoimmune disease relative to calcineurin inhibitors and anti-proliferatives, but overall efficacy may be limited due to their collateral effect of simultaneously blocking CTLA-4 coinhibitory signals. As such, current investigations into the potential of selective CD28 blockade to block the costimulatory potential of CD28 while exploiting the coinhibitory effects of CTLA-4 are promising. However, as selective CD28 blockade inhibits the activity of both effector and regulatory T cells, an important goal for the future is the design of therapies that will maximize the attenuation of effector responses while preserving the suppressive function of T regulatory cells.

Immunosuppression in the elderly renal allograft recipient: a systematic review

BACKGROUND

The Elderly are the fastest growing part of kidney transplant recipients. The best immunosuppressive strategy is unknown.

METHODS

We performed a systematic search of randomized controlled trials and observational studies focused on safety and efficacy of different immunosuppression strategies in elderly kidney recipients. Data extraction and risk of bias evaluation were systematically performed.

RESULTS

Ten studies were included: 2 randomized clinical trials and 8 observational. A marginal benefit was found for early renal function with delayed tacrolimus or complete tacrolimus avoidance using mycophenolate mofetil (MMF). Observational cohort studies looked at different antibody induction strategies, calcineurin-inhibitors based maintenance immunosuppression, calcineurin-inhibitor-free sirolimus-based therapy and use of MMF versus azathioprine. Treatment with interleukin-2 receptor antibody induction, calcineurin-inhibitor minimization with MMF and steroid minimization is advisable in the low immunologic risk elderly recipient, considering the increased risk of toxicities, infection and malignancies. In the high immunologic risk elderly recipient, taking into account the morbid consequences of acute rejection in the elderly, observational studies support antibody induction with depletive antibodies, calcineurin-inhibitor, MMF and steroids; calcineurin-inhibitor-minimization is not recommended.

CONCLUSIONS

There is very limited evidence for the benefits and harms of different immunosuppression strategies in the elderly. Most of the published literature are observational studies, and randomized controlled trials are urgently needed.

Minimising steroids in lupus nephritis – will B cell depletion pave the way?

The aim of this review is to briefly explore how steroids came to be a presumed adjunct to all treatment regimens for lupus nephritis, despite being the main cause of long term damage among patients with lupus and despite increasingly effective alternative agents. I then go on to compare and contrast how differently immunosuppression regimens have developed in the world of solid organ transplantation. Almost from the start of transplantation a clear goal was to develop steroid sparing regimens – and now units such as our own routinely use induction with a biological, a single week of steroids and then monotherapy with tacrolimus. There has been a clear trend of using biologicals as induction agents and less immunosuppression in the long run but with improved outcomes. The drive has not been the same in lupus nephritis despite there being almost no evidence to support the use of steroids and certainly nothing to suggest correct dosage and timing. Rituximab, a B cell depleting antibody, offers great promise as a treatment agent despite the negative randomised control LUNAR trial. I briefly review our own data, demonstrating that early use of rituximab in lupus nephritis allows omission of oral steroids with excellent rates of remission (complete and partial). I review why the LUNAR trial should not discourage the use of rituximab. Finally, I introduce the RITUXILUP trial, a multicentre randomised controlled trial we are developing to formally evaluate our oral steroid avoiding regimen against a standard treatment regimen of mycophenolate mofetil and steroids. We have to follow the lead of our transplant colleagues and challenge the assumption that the future for lupus nephritis cannot be steroid free.

The role of basiliximab in the evolving renal transplantation immunosuppression protocol

Basiliximab is a chimeric mouse-human monoclonal antibody directed against the alpha chain of the interleukin-2 (IL-2) receptor on activated T lymphocytes. It was shown in phase III trials to reduce the number and severity of acute rejection episodes in the first year following renal transplantation in adults and children, with a reasonable cost-benefit ratio. The drug does not increase the incidence of opportunistic infections or malignancies above baseline in patients treated with conventional calcineurin inhibitor-based immunosuppression. In the field of renal transplantation, basiliximab does not increase kidney or patient survival, despite the reduction in the number of rejection episodes. Basiliximab may reduce the incidence of delayed graft function. In comparison with lymphocyte-depleting antibodies basiliximab appears to have equal efficacy in standard immunological risk patients. Recently, IL-2 receptor monoclonal antibodies have been used with the objective of reducing or eliminating the more toxic elements of the standard immunosuppression protocol. Several trials have incorporated basiliximab in protocols designed to avoid or withdraw rapidly corticosteroids, as well as protocols which substitute target-of-rapamycin (TOR) inhibitors for calcineurin inhibitors.

Induction treatment with monoclonal antibodies for heart transplantation

Individualization of induction therapy for heart transplantation (HT) is needed, given that only patients at significant risk for fatal rejection seem to present a favorable risk-benefit ratio. The question whether monoclonal interleukin 2 antagonists or antilymphocyte antibodies should be recommended remains unanswered. As most studies suggest that they have similar efficacy in preventing acute rejection, other variables related to safety or management costs should be taken into account. The cytokine release syndrome, associated with the use of OKT3, complicates management of HT patient. The experience in our center with 2 consecutive cohorts, treated with basiliximab (BAS) and OKT3, respectively, suggests that the use of BAS is associated, in addition to similar immunosuppressive efficacy and better safety profile than OKT3, with simpler patient management during the initial hospital stay, which could be associated with a reduction in posttransplant costs. Because few centers continue to use OKT3 as induction therapy in HT, more studies comparing cost-effectiveness of BAS vs polyclonal antilymphocyte antibodies (ATG) are needed.

Anti-interleukin-2 receptor antibodies-basiliximab and daclizumab-for the prevention of acute rejection in renal transplantation

The use of antibody induction after kidney transplantation has increased from 25% to 63% in the past decade and roughly one half of the induction agent used is anti-interleukin-2 receptor antibody (IL-2RA, ie, basiliximab or daclizumab). When combined with calcineurin inhibitor (CNI)-based immunosuppression, IL-2RAs have been shown to reduce the incidence of acute rejection, one of the predictors of poor graft survival, without increasing risks of infections and malignancies in kidney transplantation. For low-immunological-risk patients, IL-2RAs, as compared with lymphocyte-depleting antibodies, are equally efficacious and have better safety profiles. For high-risk patients, however, IL-2RAs may be inferior to lymphocyte-depleting antibodies for the prophylaxis of acute rejection. In an effort to reduce toxicities of other immunosuppressive medications without increasing the risk of acute rejection and chronic graft loss, IL-2RAs have often been combined with steroid- and CNI-sparing immunosuppression protocols. More data support the benefits of early steroid withdrawal with IL-2RA in low-risk patients, but preferred induction therapy for high-risk patients has yet to be determined. Although CNI-sparing protocols with IL-2RA may preserve renal function and improve long-term survival in selected patients, further studies are needed to identify those who benefit most from this strategy.

Lifetime cost-effectiveness of calcineurin inhibitor withdrawal after de novo renal transplantation

After renal transplantation, immunosuppressive regimens associated with high short-term survival rates are not necessarily associated with high long-term survival rates, suggesting that regimens may need to be optimized over time. Calcineurin inhibitor (CNI) withdrawal from a sirolimus-based immunosuppressive regimen may maximize the likelihood of long-term graft and patient survival by minimizing CNI-associated nephrotoxicity. In this study, a lifetime Markov model was created to compare the cost-effectiveness of a sirolimus-based CNI withdrawal regimen (sirolimus plus steroids) with other common CNI-containing regimens in adult de novo renal transplantation patients. Long-term graft survival was estimated by renal function and data from published studies and the US transplant registry, including short- and long-term outcomes, utility weights, and health-state costs were incorporated. Drug costs were based on average daily consumption and wholesale acquisition costs. The model suggests that treatment with sirolimus plus steroids is more efficacious and less costly than regimens consisting of a CNI, mycophenolate mofetil, and steroids; therefore, CNI withdrawal not only shows potential for long-term clinical benefits but also is expected to be cost-saving over a patient's life compared with the most commonly prescribed CNI-containing regimens.

A Randomized Multicenter Comparison of Basiliximab and Muromonab (OKT3) in Heart Transplantation: SIMCOR Study

BACKGROUND

Antilymphocytic antibodies have been long used for the prevention of acute rejection early after heart transplantation (HTx), but their adverse effects have limited their widespread use. Our aim was to evaluate the safety, tolerability, and efficacy of the novel anti-CD25 antibody basiliximab (BAS) compared with muromonab (OKT3).

PATIENTS AND METHODS

In this multicenter study, 99 patients were randomly assigned to receive either BAS or OKT3 in the early post-HTx period. The primary endpoint was safety and tolerability. Specific safety variables were predefined for a better comparison of adverse effects. Secondary endpoints concerning anti-rejection efficacy were also evaluated.

RESULTS

No adverse events related to study medication were found in the BAS group, whereas 23 were observed among patients receiving OKT3 (P<0.0001). The proportion of patients with predefined adverse events day 4 post-HTx was much higher with OKT3 than with BAS (43% vs. 4%; P<0.0001). Fever, acute pulmonary edema, hypotension, and other complications accounted for most of the difference. At 1-year follow-up, biopsy-proven rejection episodes grade>or=3A had occurred in 39.6% of BAS patients versus 40.4% of OKT3 patients (P=0.87). There were no differences in terms of severity and timing of acute rejection episodes. The number of infectious episodes, complications not related to study medication, and actuarial survival were similar in both groups.

CONCLUSION

In this HTx study, induction therapy with BAS was safer and better tolerated than OKT3, without significant differences in efficacy outcomes.

Toxicity-sparing protocols using mycophenolate mofetil in renal transplantation

The introduction of triple-therapy regimens that include a calcineurin inhibitor (CNI), steroids, and azathioprine greatly reduced the risk of acute rejection in renal transplantation. However, the long-term use of both CNIs and steroids is associated with serious toxicities that ultimately can impact patient/graft survival. Mycophenolate mofetil (MMF), a highly effective immunosuppressant with no known nephrotoxicity, has been shown to provide benefits in preserving long-term renal allograft function relative to azathioprine. For these reasons, MMF has become an integral component of toxicity-sparing maintenance regimens that seek to minimize patient exposure to CNIs and steroids. This paper provides an overview of current strategies for reducing the toxicities associated with these agents, which include both withdrawal and avoidance regimens with or without induction therapy. Data are accumulating that toxicity-sparing regimens involving MMF are safe and decrease the risk of side effects that accompany the use of CNIs and steroids. Future studies will determine how to best implement these regimens in the renal transplant population.

Induction Therapy with Basiliximab Allows Delayed Initiation of Cyclosporine and Preserves Renal Function After Cardiac Transplantation

BACKGROUND

Cyclosporine (CsA) is frequently initiated as induction therapy in patients undergoing orthotopic heart transplantation, but our experience has identified a significant rate of post-operative renal dysfunction. We therefore devised a renal-sparing cyclosporine-free induction regimen consisting of the early administration basiliximab, an interleukin-2 receptor monoclonal antibody, followed by the late initiation of cyclosporine on post-operative Day 4.

METHODS

Between September 1998 and December 1999, we treated 25 patients at risk for post-operative renal dysfunction (high-risk basiliximab group) with the new induction regimen and another 33 patients not at risk (low-risk CsA group) for renal dysfunction with our standard cyclosporine protocol. We identified a historical control group (1996 through 1998) of 32 patients at risk for renal dysfunction (high-risk CsA group) who had received our standard cyclosporine protocol.

RESULTS

The increase in serum creatinine levels after transplantation was less in the high-risk basiliximab group (-0.1 +/- 0.7) than in the high-risk CsA group (0.5 +/- 1.0, p < 0.02) and comparable to the low-risk CsA group (0.03 +/- 0.6). The basiliximab protocol did not increase rejection; the percentage of rejection episodes was high-risk basiliximab, 0; high-risk CsA, 13; and low-risk CsA, 3 (p = .13).

CONCLUSION

Basiliximab induction therapy allows delayed initiation of cyclosporine after cardiac transplantation without an increase in rejection and reduces the risk of post-operative renal dysfunction.

Costimulation blockade with belatacept in renal transplantation

BACKGROUND

Renal transplantation is the standard of care for patients with end-stage renal disease. Although maintenance immunosuppression with calcineurin inhibitors yields excellent one-year survival, it is associated over the long term with high rates of death and graft loss, owing in part to the adverse renal, cardiovascular, and metabolic effects of these agents. The use of potentially less toxic agents, such as belatacept, a selective blocker of T-cell activation, may improve outcomes.

METHODS

We randomly assigned renal-transplant recipients to receive an intensive or a less-intensive regimen of belatacept or cyclosporine. All patients received induction therapy with basiliximab, mycophenolate mofetil, and corticosteroids. The primary objective was to demonstrate the noninferiority of belatacept over cyclosporine in the incidence of acute rejection at six months (with an upper bound of the 95 percent confidence interval around the treatment difference of less than 20 percent).

RESULTS

At six months, the incidence of acute rejection was similar among the groups: 7 percent for intensive belatacept, 6 percent for less-intensive belatacept, and 8 percent for cyclosporine. At 12 months, the glomerular filtration rate was significantly higher with both intensive and less-intensive belatacept than it was with cyclosporine (66.3, 62.1, and 53.5 ml per minute per 1.73 m2, respectively), and chronic allograft nephropathy was less common with both regimens of belatacept than with cyclosporine (29 percent, 20 percent, and 44 percent, respectively). Lipid levels and blood-pressure values were similar or slightly lower in the belatacept groups, despite the greater use of lipid-lowering and antihypertensive medications in the cyclosporine group.

CONCLUSIONS

Belatacept, an investigational selective costimulation blocker, did not appear to be inferior to cyclosporine as a means of preventing acute rejection after renal transplantation. Belatacept may preserve the glomerular filtration rate and reduce the rate of chronic allograft nephropathy.

Steroid avoidance in renal transplantation using basiliximab induction, cyclosporine-based immunosuppression and protocol biopsies

BACKGROUND

Reducing chronic steroid exposure is important to minimize steroid-related morbidity, particularly for susceptible renal transplant recipients. Steroid-free and steroid-sparing protocols have shown benefits, but safety has not been established for all populations. We investigated the safety of steroid avoidance (SA) in a population including African-Americans, using modern immunosuppression with protocol biopsy monitoring.

METHODS

A randomized-controlled SA trial (early discontinuation, days 2-7) was conducted in a population (n = 77) including African-Americans and cadaveric kidney recipients. Patients received basiliximab, cyclosporine (CsA), and mycophenolate mofetil (MMF). In controls, steroids were tapered to 5 mg prednisone/d by day 30. Protocol biopsies were performed (1, 6, 12 and 24 months) to evaluate subclinical acute rejection (SCAR) and chronic allograft nephropathy (CAN).

RESULTS

The SA did not result in significantly higher incidences of graft loss, AR, SCAR, CAN, or renal fibrosis. SA patients experienced similar renal function, comparable serum lipid levels, and a trend toward fewer cases of new-onset diabetes. Clinical outcomes of African-American and non-African-American patients did not significantly differ.

CONCLUSIONS

The SA is safe in the context of basiliximab induction and CsA-based immunosuppression. This protocol could minimize steroid-related side effects in susceptible groups, including African-Americans, without increasing the risk of AR or graft failure.

Efficacy and safety of basiliximab in kidney transplantation

The efficacy and safety of basiliximab, in combination with different maintenance regimens, are extensively addressed in the available literature. Basiliximab reduces the incidence of acute rejection, allows a safe reduction of steroid dosage, and is associated with economic savings, although there is substantially no proof that basiliximab prolongs either patient or graft survival. Initial basiliximab administration entails a low-risk and is associated with fewer adverse events than T cell depleting agents. However, life-threatening reactions were reported following re-exposure to basiliximab in recipients who lost graft function early after transplantation and, therefore, discontinued all immunosuppressive agents.

Induction Therapy with Basiliximab versus Thymoglobulin in African-American Kidney Transplant Recipients

BACKGROUND

It has been suggested that the use of antilymphocyte induction therapy in African-American (AA) renal transplant recipients reduces the risk of acute rejection (AR) and improves graft survival. It is not clear whether the efficacy of basiliximab (BSX) is different from that of Thymoglobulin (ATG) in this regard.

METHODS

We retrospectively assessed the effect of induction therapy with BSX versus ATG in 88 AA renal allograft recipients receiving transplants at our center between July 2001 and June 2003 and followed for 19+/-7 months. All patients were maintained on mycophenolate mofetil, prednisone, and either tacrolimus or sirolimus. Study endpoints included patient and graft survival, graft function, and incidence of AR and cytomegalovirus infection. Regression models were used to evaluate the independent effect of each induction agent on these endpoints.

RESULTS

Thirty-six patients received ATG, and 52 received BSX. The groups were comparable with regard to donor race and age, and recipient sex, body mass index, human leukocyte antigen (HLA) matching, and hepatitis C virus serostatus. The ATG group was younger, more likely to receive retransplant, had longer duration of end-stage renal disease and higher panel reactive antibody, and was less likely to receive live-donor organs. However, after adjusting for all these variables, graft outcomes, as well as renal function, were comparable between the two induction groups. We found that the degree of HLA mismatch, delayed graft function, and AR were the only significant predictors of graft loss.

CONCLUSION

The results of our study suggest that the choice of induction agent may not have a major impact on graft outcomes in AA renal-allograft recipients.