Polyclonal and monoclonal antibodies for treating acute rejection episodes in kidney transplant recipients

Polyclonal and monoclonal antibodies for treating acute rejection episodes in kidney transplant recipients

BACKGROUND

Registry data shows that the incidence of acute rejection has been steadily falling. Approximately 10% to 35% of kidney recipients will undergo treatment for at least one episode of acute rejection within the first post-transplant year. Treatment options include pulsed steroid therapy, the use of an antibody preparation, the alteration of background immunosuppression, or combinations of these options. Over recent years, new treatment strategies have evolved, and in many parts of the world there has been an increase in use of tacrolimus and mycophenolate and a reduction in the use of cyclosporin and azathioprine use as baseline immunosuppression to prevent acute rejection. There are also global variations in use of polyclonal and monoclonal antibodies to treat acute rejection. This is an update of a review published in 2006.

OBJECTIVES

The aim of this systematic review was to: (1) to evaluate the relative and absolute effects of different classes of antibody preparation in preventing graft loss and resolving cellular or humoral rejection episodes when used as a treatment for first episode of rejection in kidney transplant recipients; (2) evaluate the relative and absolute effects of different classes of antibody preparation in preventing graft loss and resolving cellular or humoral rejection episodes when used as a treatment for steroid-resistant rejection in kidney transplant recipients; (3) determine how the benefits and adverse events vary for each type of antibody preparation; and (4) determine how the benefits and harms vary for different formulations of antibody within each type.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 18 April 2017 through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in all languages comparing all mono- and polyclonal antibody preparations, given in combination with any other immunosuppressive agents, for the treatment of cellular or humoral graft rejection, when compared to any other treatment for acute rejection were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias of the included studies and extracted data. Statistical analyses were performed using a random-effects model and results expressed as risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 11 new studies (18 reports, 346 participants) in this update, bring the total number of included studies to 31 (76 reports, 1680 participants). Studies were generally small, incompletely reported, especially for potential harms, and did not define outcome measures adequately. The risk of bias was inadequate or unclear risk for random sequence generation (81%), allocation concealment (87%) and other bias (87%). There were, however, a predominance of low risk of bias for blinding (75%) and incomplete outcome data (80%) across all the studies. Selective reporting had a mixture of low (58%), high (29%), and unclear (13%) risk of bias.Seventeen studies (1005 participants) compared therapies for first acute cellular rejection episodes. Antibody therapy was probably better than steroid in reversing acute cellular rejection (RR 0.50, 95% CI 0.30 to 0.82; moderate certainty) and preventing subsequent rejection (RR 0.70, 95% CI 0.50 to 0.99; moderate certainty), may be better for preventing graft loss (death censored: (RR 0.80, 95% CI 0.57 to 1.12; low certainty) but there was little or no difference in death at one year. Adverse effects of treatment (including fever, chills and malaise following drug administration) were probably reduced with steroid therapy (RR 23.88, 95% CI 5.10 to 111.86; I2 = 16%; moderate certainty).Twelve studies (576 patients) investigated antibody treatment for steroid-resistant rejection. There was little or no benefit of muromonab-CD3 over ATG or ALG in reversing rejection, preventing subsequent rejection, or preventing graft loss or death. Two studies compared the use of rituximab for treatment of acute humoral rejection (58 patients). Muromonab-CD3 treated patients suffered three times more than those receiving either ATG or T10B9, from a syndrome of fever, chills and malaise following drug administration (RR 3.12, 95% CI 1.87 to 5.21; I2 = 31%), and experienced more neurological side effects (RR 13.10 95% CI 1.43 to 120.05; I2 = 36%) (low certainty evidence).There was no evidence of additional benefit from rituximab in terms of either reversal of rejection (RR 0.94, 95% CI 0.54 to 1.64), or graft loss or death 12 months (RR 1.0, 95% CI 0.23 to 4.35). Rituximab plus steroids probably increases the risk of urinary tract infection/pyelonephritis (RR 5.73, 95% CI 1.80 to 18.21).

AUTHORS' CONCLUSIONS

In reversing first acute cellular rejection and preventing graft loss, any antibody is probably better than steroid, but there is little or no difference in subsequent rejection and patient survival. In reversing steroid-resistant rejection there was little or no difference between different antibodies over a period of 12 months, with limited data beyond that time frame. In treating acute humoral rejection, there was no evidence that the use of antibody therapy conferred additional benefit in terms of reversal of rejection, or death or graft loss.Although this is an updated review, the majority of newer included studies provide additional evidence from the cyclosporin/azathioprine era of kidney transplantation and therefore conclusions cannot necessarily be extrapolated to patients treated with more contemporary immunosuppressive regimens which include tacrolimus/mycophenolate or sirolimus. However, many kidney transplant centres around the world continue to use older immunosuppressive regimes and the findings of this review remain strongly relevant to their clinical practice.Larger studies with standardised reproducible outcome criteria are needed to investigate the outcomes and risks of antibody treatments for acute rejection in kidney transplant recipients receiving contemporary immunosuppressive regimes.

Polyclonal and monoclonal antibodies for induction therapy in kidney transplant recipients

BACKGROUND

Prolonging kidney transplant survival is an important clinical priority. Induction immunosuppression with antibody therapy is recommended at transplantation and non-depleting interleukin-2 receptor monoclonal antibodies (IL2Ra) are considered first line. It is suggested that recipients at high risk of rejection should receive lymphocyte-depleting antibodies but the relative benefits and harms of the available agents are uncertain.

OBJECTIVES

We aimed to: evaluate the relative and absolute effects of different antibody preparations (except IL2Ra) when used as induction therapy in kidney transplant recipients; determine how the benefits and adverse events vary for each antibody preparation; determine how the benefits and harms vary for different formulations of antibody preparation; and determine whether the benefits and harms vary in specific subgroups of recipients (e.g. children and sensitised recipients).

SEARCH METHODS

Randomised controlled trials (RCTs) comparing monoclonal or polyclonal antibodies with placebo, no treatment, or other antibody therapy in adults and children who had received a kidney transplant.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing monoclonal or polyclonal antibodies with placebo, no treatment, or other antibody therapy in adults and children who had received a kidney transplant.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Dichotomous outcomes are reported as relative risk (RR) and continuous outcomes as mean difference (MD) together with their 95% confidence intervals (CI).

MAIN RESULTS

We included 99 studies (269 records; 8956 participants; 33 with contemporary agents). Methodology was incompletely reported in most studies leading to lower confidence in the treatment estimates.Antithymocyte globulin (ATG) prevented acute graft rejection (17 studies: RR 0.63, 95% CI 0.51 to 0.78). The benefits of ATG on graft rejection were similar when used with (12 studies: RR 0.61, 0.49 to 0.76) or without (5 studies: RR 0.65, 0.43 to 0.98) calcineurin inhibitor (CNI) treatment. ATG (with CNI therapy) had uncertain effects on death (3 to 6 months, 3 studies: RR 0.41, 0.13 to 1.22; 1 to 2 years, 5 studies: RR 0.75, 0.27 to 2.06; 5 years, 2 studies: RR 0.94, 0.11 to 7.81) and graft loss (3 to 6 months, 4 studies: RR 0.60, 0.34 to 1.05; 1 to 2 years, 3 studies: RR 0.65, 0.36 to 1.19). The effect of ATG on death-censored graft loss was uncertain at 1 to 2 years and 5 years. In non-CNI studies, ATG had uncertain effects on death but reduced death-censored graft loss (6 studies: RR 0.55, 0.38 to 0.78). When CNI and older non-CNI studies were combined, a benefit was seen with ATG at 1 to 2 years for both all-cause graft loss (7 studies: RR 0.71, 0.53 to 0.95) and death-censored graft loss (8 studies: RR 0.55, 0.39 to 0.77) but not sustained longer term. ATG increased cytomegalovirus (CMV) infection (6 studies: RR 1.55, 1.24 to 1.95), leucopenia (4 studies: RR 3.86, 2.79 to 5.34) and thrombocytopenia (4 studies: RR 2.41, 1.61 to 3.61) but had uncertain effects on delayed graft function, malignancy, post-transplant lymphoproliferative disorder (PTLD), and new onset diabetes after transplantation (NODAT).Alemtuzumab was compared to ATG in six studies (446 patients) with early steroid withdrawal (ESW) or steroid minimisation. Alemtuzumab plus steroid minimisation reduced acute rejection compared to ATG at one year (4 studies: RR 0.57, 0.35 to 0.93). In the two studies with ESW only in the alemtuzumab arm, the effect of alemtuzumab on acute rejection at 1 year was uncertain compared to ATG (RR 1.27, 0.50 to 3.19). Alemtuzumab had uncertain effects on death (1 year, 2 studies: RR 0.39, 0.06 to 2.42; 2 to 3 years, 3 studies: RR 0.67, 95% CI 0.15 to 2.95), graft loss (1 year, 2 studies: RR 0.39, 0.13 to 1.30; 2 to 3 years, 3 studies: RR 0.98, 95% CI 0.47 to 2.06), and death-censored graft loss (1 year, 2 studies: RR 0.38, 0.08 to 1.81; 2 to 3 years, 3 studies: RR 2.45, 95% CI 0.67 to 8.97) compared to ATG. Creatinine clearance was lower with alemtuzumab plus ESW at 6 months (2 studies: MD -13.35 mL/min, -23.91 to -2.80) and 2 years (2 studies: MD -12.86 mL/min, -23.73 to -2.00) compared to ATG plus triple maintenance. Across all 6 studies, the effect of alemtuzumab versus ATG was uncertain on all-cause infection, CMV infection, BK virus infection, malignancy, and PTLD. The effect of alemtuzumab with steroid minimisation on NODAT was uncertain, compared to ATG with steroid maintenance.Alemtuzumab plus ESW compared with triple maintenance without induction therapy had uncertain effects on death and all-cause graft loss at 1 year, acute rejection at 6 months and 1 year. CMV infection was increased (2 studies: RR 2.28, 1.18 to 4.40). Treatment effects were uncertain for NODAT, thrombocytopenia, and malignancy or PTLD.Rituximab had uncertain effects on death, graft loss, acute rejection and all other adverse outcomes compared to placebo.

AUTHORS' CONCLUSIONS

ATG reduces acute rejection but has uncertain effects on death, graft survival, malignancy and NODAT, and increases CMV infection, thrombocytopenia and leucopenia. Given a 45% acute rejection risk without ATG induction, seven patients would need treatment to prevent one having rejection, while incurring an additional patient experiencing CMV disease for every 12 treated. Excluding non-CNI studies, the risk of rejection was 37% without induction with six patients needing treatment to prevent one having rejection.In the context of steroid minimisation, alemtuzumab prevents acute rejection at 1 year compared to ATG. Eleven patients would require treatment with alemtuzumab to prevent 1 having rejection, assuming a 21% rejection risk with ATG.Triple maintenance without induction therapy compared to alemtuzumab combined with ESW had similar rates of acute rejection but adverse effects including NODAT were poorly documented. Alemtuzumab plus steroid withdrawal would cause one additional patient experiencing CMV disease for every six patients treated compared to no induction and triple maintenance, in the absence of any clinical benefit. Overall, ATG and alemtuzumab decrease acute rejection at a cost of increased CMV disease while patient-centred outcomes (reduced death or lower toxicity) do not appear to be improved.

Disruptions in the supply of medications used in transplantation: implications and management strategies for the transplant clinician

Drug shortages are a threat to patient care and public health, and the number of drugs on shortage is growing at an exponential rate. The major therapy areas affected by these shortages are oncology, anti-infective, cardiovascular and central nervous system. However, drugs utilized in the transplant patient population have not been exempt, and can have significant influence on posttransplant outcomes. The purpose of this review is to discuss the current and historical solid organ transplant-related disruptions in the supply of medications and implications on patient care and safety. Transplant centers should be armed with an implementation plan when imperative transplant-related drugs such as tacrolimus, mycophenolate, or antithymocyte globulin go on shortage. This plan should provide steps to manage the shortage, and provide effective therapeutic alternatives.

Rationale and design of the RIACT-study: a multi-center placebo controlled double blind study to test the efficacy of RItuximab in Acute Cellular tubulointerstitial rejection with B-cell infiltrates in renal Transplant patients: study protocol for a randomized controlled trial

BACKGROUND

Acute kidney allograft rejection is a major cause for declining graft function and has a negative impact on the long-term graft survival. The majority (90%) of acute rejections are T-cell mediated and, therefore, the anti-rejection therapy targets T-cell-mediated mechanisms of the rejection process. However, there is increasing evidence that intragraft B-cells are also important in the T-cell-mediated rejections. First, a significant proportion of patients with acute T-cell-mediated rejection have B-cells present in the infiltrates. Second, the outcome of these patients is inferior, which has been related to an inferior response to the conventional anti-rejection therapy. Third, treatment of these patients with an anti-CD20 antibody (rituximab) improves the allograft outcome as reported in single case observations and in one small study. Despite the promise of these observations, solid evidence is required before incorporating this treatment option into a general treatment recommendation.

METHODS/DESIGN

The RIACT study is designed as a randomized, double-blind, placebo-controlled, parallel group multicenter Phase III study. The study examines whether rituximab, in addition to the standard treatment with steroid-boli, leads to an improved one-year kidney allograft function, compared to the standard treatment alone in patients with acute T-cell mediated tubulointerstitial rejection and significant B-cell infiltrates in their biopsies. A total of 180 patients will be recruited.

DISCUSSION

It is important to clarify the relevance of anti-B cell targeting in T-cell mediated rejection and answer the question whether this novel concept should be incorporated in the conventional anti-rejection therapy.

TRIAL REGISTRATION

Clinical trials gov. number: NCT01117662.

Acute respiratory failure in kidney transplant recipients: a multicenter study

INTRODUCTION

Data on pulmonary complications in renal transplant recipients are scarce. The aim of this study was to evaluate acute respiratory failure (ARF) in renal transplant recipients.

METHODS

We conducted a retrospective observational study in nine transplant centers of consecutive kidney transplant recipients admitted to the intensive care unit (ICU) for ARF from 2000 to 2008.

RESULTS

Of 6,819 kidney transplant recipients, 452 (6.6%) required ICU admission, including 200 admitted for ARF. Fifteen (7.5%) of these patients had combined kidney-pancreas transplantations. The most common causes of ARF were bacterial pneumonia (35.5%), cardiogenic pulmonary edema (24.5%) and extrapulmonary acute respiratory distress syndrome (ARDS) (15.5%). Pneumocystis pneumonia occurred in 11.5% of patients. Mechanical ventilation was used in 93 patients (46.5%), vasopressors were used in 82 patients (41%) and dialysis was administered in 104 patients (52%). Both the in-hospital and 90-day mortality rates were 22.5%. Among the 155 day 90 survivors, 115 patients (74.2%) were dialysis-free, including 75 patients (65.2%) who recovered prior renal function. Factors independently associated with in-hospital mortality were shock at admission (odds ratio (OR) 8.70, 95% confidence interval (95% CI) 3.25 to 23.29), opportunistic fungal infection (OR 7.08, 95% CI 2.32 to 21.60) and bacterial infection (OR 2.53, 95% CI 1.07 to 5.96). Five factors were independently associated with day 90 dialysis-free survival: renal Sequential Organ Failure Assessment (SOFA) score on day 1 (OR 0.68/SOFA point, 95% CI 0.52 to 0.88), bacterial infection (OR 0.43, 95% CI 0.21 to 0.90), three or four quadrants involved on chest X-ray (OR 0.44, 95% CI 0.21 to 0.91), time from hospital to ICU admission (OR 0.98/day, 95% CI 0.95 to 0.99) and oxygen flow at admission (OR 0.93/liter, 95% CI 0.86 to 0.99).

CONCLUSIONS

In kidney transplant recipients, ARF is associated with high mortality and graft loss rates. Increased Pneumocystis and bacterial prophylaxis might improve these outcomes. Early ICU admission might prevent graft loss.

Immunosuppression armamentarium in 2010: mechanistic and clinical considerations

Effective immunosuppression is the key to successful organ transplantation, with success being defined as minimal rejection risk with concomitant minimal drug toxicities. Despite the general recognition of this fact, a paucity of appropriate clinical trials in children has contributed to lack of standardization of clinical management regimens, resulting in an extensive diversity of favored approaches. Nonetheless, although consensus has not been reached on the ideal approach to immunosuppression in pediatric transplantation, new drug therapies have contributed to a continuing improvement in graft and patient survival. Future clinical research must focus on diminishing the extensive burden of toxicities of these therapeutic agents in children.

Induction Therapy in Cardiac Transplantation: When and Why?

Induction therapy has continued to be a subject of controversy in heart transplantation for more than 20 years. It is an example of a therapy that is logical, and ought to be better than "doing without." However, a careful review of the evidence suggests otherwise. Except for patients where the benefits clearly outweigh the short and long-term risks, the use of induction therapy should be avoided. In immunosuppression, as in life, there is no "free lunch." Clinicians need to be certain they fully understand what they are ordering when asking for induction therapy to be administered to their patients.