John F. Neylan

Interleukin-2–Receptor Blockade with Daclizumab to Prevent Acute Rejection in Renal Transplantation

Background Monoclonal antibodies that block the high-affinity interleukin-2 receptor expressed on alloantigen-reactive T lymphocytes may cause selective immunosuppression. Daclizumab is a genetically engineered human IgG1 monoclonal antibody that binds specifically to the α chain of the interleukin-2 receptor and may thus reduce the risk of rejection after renal transplantation. Methods We administered daclizumab (1.0 mg per kilogram of body weight) or placebo intravenously before transplantation and once every other week afterward, for a total of five doses, to 260 patients receiving first cadaveric kidney grafts and immunosuppressive therapy with cyclosporine, azathioprine, and prednisone. The patients were followed at regular intervals for 12 months. The primary end point was the incidence of biopsy-confirmed acute rejection within six months after transplantation. Results Of the 126 patients given daclizumab, 28 (22 percent) had biopsy-confirmed episodes of acute rejection, as compared with 47 of the ...

Conversion from calcineurin inhibitors to sirolimus maintenance therapy in renal allograft recipients: 24-month efficacy and safety results from the CONVERT trial.

Background. The efficacy and safety of converting maintenance renal transplant recipients from calcineurin inhibitors (CNIs) to sirolimus (SRL) was evaluated. Methods. Eight hundred thirty renal allograft recipients, 6 to 120 months posttransplant and receiving cyclosporine or tacrolimus, were randomly assigned to continue CNI (n=275) or convert from CNI to SRL (n=555). Primary endpoints were calculated Nankivell glomerular filtration rate (GFR; stratified at baseline: 20–40 vs. >40 mL/min) and the cumulative rates of biopsy-confirmed acute rejection (BCAR), graft loss, or death at 12 months. Enrollment in the 20 to 40 mL/min stratum was halted prematurely because of a higher incidence of safety endpoints in the SRL conversion arm. Results. Intent-to-treat analyses at 12 and 24 months showed no significant treatment difference in GFR in the baseline GFR more than 40 mL/min stratum. On-therapy analysis of this cohort showed significantly higher GFR at 12 and 24 months after SRL conversion. Rates of BCAR, graft survival, and patient survival were similar between groups. Median urinary protein-to-creatinine ratios (UPr/Cr) were similar at baseline but increased significantly after SRL conversion. Malignancy rates were significantly lower at 12 and 24 months after SRL conversion. Post hoc analyses identified a subgroup with baseline GFR more than 40 mL/min and UPr/Cr less than or equal to 0.11, whose risk-benefit profile was more favorable after conversion than that for the overall SRL conversion cohort. Conclusions. At 2 years, SRL conversion among patients with baseline GFR more than 40 mL/min was associated with excellent patient and graft survival, no difference in BCAR, increased urinary protein excretion, and a lower incidence of malignancy compared with CNI continuation. Superior renal function was observed among patients who remained on SRL through 12 to 24 months, particularly in the subgroup of patients with baseline GFR more than 40 mL/min and UPr/Cr less than or equal to 0.11.

Sirolimus Therapy after Early Cyclosporine Withdrawal Reduces the Risk for Cancer in Adult Renal Transplantation

Sirolimus (SRL) is a mammalian target of rapamycin inhibitor that, in contrast to cyclosporine (CsA), has been shown to inhibit rather than promote cancers in experimental models. At 3 mo +/- 2 wk after renal transplantation, 430 of 525 enrolled patients were randomly assigned to remain on SRL-CsA-steroids (ST) or to have CsA withdrawn and SRL troughs increased two-fold (SRL-ST). Median times to first skin and nonskin malignancies were compared between treatments using a survival analysis. Mean annualized rates of skin malignancy were calculated, and the relative risk was determined using a Poisson model. Malignancy-free survival rates for nonskin malignancies were compared using Kaplan-Meier estimates and the log-rank test. At 5 yr, the median time to a first skin carcinoma was delayed (491 versus 1126 d; log-rank test, P = 0.007), and the risk for an event was significantly lower with SRL-ST therapy (relative risk SRL-ST to SRL-CsA-ST 0.346; 95% confidence interval 0.227 to 0.526; P < 0.001, intention-to-treat analysis). The relative risks for both basal and squamous cell carcinomas were significantly reduced. Kaplan-Meier estimates of nonskin cancer were 9.6 versus 4.0% (SRL-CsA-ST versus SRL-ST; P = 0.032, intention-to-treat analysis). Nonskin cancers included those of the lung, larynx, oropharynx, kidney, gastrointestinal tract, prostate, breast, thyroid, and cervix as well as glioma, liposarcoma, astrocytoma, leukemia, lymphoma, and Kaposis sarcoma. Patients who received SRL-based, calcineurin inhibitor-free therapy after CsA withdrawal at month 3 had a reduced incidence of both skin and nonskin malignancies at 5 yr after renal transplantation compared with those who received SRL therapy combined with CsA. Longer follow-up and additional trials are needed to confirm these promising results.

Sirolimus reduces the incidence of acute rejection episodes despite lower cyclosporine doses in caucasian recipients of mismatched primary renal allografts: a phase II trial. Rapamune Study Group.

BACKGROUND The novel agent sirolimus (SRL; Rapamune; rapamycin) inhibits the immune response by a mechanism distinct from those of calcineurin antagonists or antimetabolites. This randomized, controlled, multicenter, single blind, phase II trial examined the combination of SRL, steroids, and full versus reduced doses of cyclosporine (CsA) for prophylaxis of acute renal allograft rejection. METHODS A total of 149 recipients of mismatched cadaveric- or living-donor primary renal allografts were randomized into six groups. Three groups received placebo or 1 or 3 mg/m2/day SRL, as well as steroids and full-dose CsA (Sandimmune). Three groups received steroids, reduced-dose CsA (target trough level 50% of full-dose range), and 1, 3, or 5 mg/m2/day SRL. RESULTS The incidence of biopsy-proven acute rejection episodes within the first 6 months after transplant was reduced from 32.0% in the control group to 8.5% in patients receiving SRL (1 or 3 mg/m2/day) and full-dose Sandimmune CsA (P=0.018). Similar low rates of acute rejection episodes were observed among non-African-Americans, but not African-Americans, treated with SRL and reduced-dose Sandimmune CsA. Despite the augmented immunosuppression, 1-year patient and graft survival rates did not differ significantly across groups. Adverse effects attributable to CsA, including hypertension and new-onset diabetes mellitus, were not exacerbated by SRL. Except for an increased incidence of pneumonia among patients receiving full-dose CsA and 3 mg/m2/day SRL, the incidences of opportunistic infections were similar in all treatment groups. Although SRL produced more frequent, but reversible, hematological and lipid abnormalities, it had no apparent nephrotoxic effects to exacerbate CsA-induced renal dysfunction. CONCLUSIONS SRL in combination with CsA and steroids not only lowers the incidence of biopsy-proven acute renal allograft rejection episodes, but also may permit CsA sparing, at least among Caucasian patients, without an increased risk of rejection.

Racial differences in renal transplantation after immunosuppression with tacrolimus versus cyclosporine. FK506 Kidney Transplant Study Group.

BACKGROUND Results of a multicenter, randomized, clinical trial demonstrated that tacrolimus was more effective than cyclosporine in preventing acute rejection in cadaveric renal transplant patients. As African-Americans comprised approximately 25% of the study population, their outcome was analyzed relative to the experience of Caucasian patients. METHODS Of the 205 patients randomized to tacrolimus, 56 (27.3%) were African-American and 114 (55.6%) were Caucasian. Of the 207 patients randomized to cyclosporine, 48 (23.2%) were African-American and 123 (59.4%) were Caucasian. The efficacy variables were 1-year patient survival, graft survival, and incidence of acute rejection. RESULTS The incidence of acute rejection was significantly lower in African-American and Caucasian patients treated with tacrolimus than with cyclosporine. Additionally, no African-American patient who was treated with tacrolimus experienced moderate or severe acute rejection, as determined by blinded independent review. The incidence of nephrotoxicity, cardiovascular and gastrointestinal events, malignancies, and opportunistic infections was similar between treatments and race groups. However, there was an increased incidence of posttransplant diabetes mellitus in tacrolimus-treated patients, particularly in African-Americans, and tacrolimus was associated with significantly lower lipid levels in both Caucasians and African-Americans. African-American patients required a 37% mean higher dose of tacrolimus than Caucasian patients to achieve comparable blood concentrations. CONCLUSIONS Tacrolimus is more effective than cyclosporine in preventing acute rejection in both African-American and Caucasian patients. However, tacrolimus was associated with an increased risk of posttransplant diabetes mellitus, particularly in African-Americans, which was reversible in some patients.

Results of the double-blind, randomized, multicenter, phase III clinical trial of thymoglobulin versus Atgam in the treatment of acute graft rejection episodes after renal transplantation

BACKGROUND Thymoglobulin, a rabbit anti-human thymocyte globulin, was compared with Atgam, a horse anti-human thymocyte globulin for the treatment of acute rejection after renal transplantation. METHODS A multicenter, double-blind, randomized trial with enrollment stratification based on standardized histology (Banff grading) was conducted. Subjects received 7-14 days of Thymoglobulin (1.5 mg/kg/ day) or Atgam (15 mg/kg/day). The primary end point was rejection reversal (return of serum creatinine level to or below the day 0 baseline value). RESULTS A total of 163 patients were enrolled at 25 transplant centers in the United States. No differences in demographics or transplant characteristics were noted. Intent-to-treat analysis demonstrated that Thymoglobulin had a higher rejection reversal rate than Atgam (88% versus 76%, P=0.027, primary end point). Day 30 graft survival rates (Thymoglobulin 94% and Atgam 90%, P=0.17), day 30 serum creatinine levels as a percentage of baseline (Thymoglobulin 72% and Atgam 80%; P=0.43), and improvement in posttreatment biopsy results (Thymoglobulin 65% and Atgam 50%; P=0.15) were not statistically different. T-cell depletion was maintained more effectively with Thymoglobulin than Atgam both at the end of therapy (P=0.001) and at day 30 (P=0.016). Recurrent rejection, at 90 days after therapy, occurred less frequently with Thymoglobulin (17%) versus Atgam (36%) (P=0.011). A similar incidence of adverse events, post-therapy infections, and 1-year patient and graft survival rates were observed with both treatments. CONCLUSIONS Thymoglobulin was found to be superior to Atgam in reversing acute rejection and preventing recurrent rejection after therapy in renal transplant recipients.

Early cyclosporine withdrawal from a sirolimus‐based regimen results in better renal allograft survival and renal function at 48 months after transplantation

We report the 48‐month results of a trial testing whether withdrawal of cyclosporine (CsA) from a sirolimus (SRL)‐CsA‐steroid (ST) regimen would impact renal allograft survival. Eligible patients receiving SRL‐CsA‐ST from transplantation were randomly assigned at 3 months to remain on triple therapy (SRL‐CsA‐ST, n = 215) or to have CsA withdrawn and SRL trough concentrations increased (SRL‐ST, n = 215). SRL‐ST therapy resulted in significantly better graft survival, either when including death with a functioning graft as an event (84.2% vs. 91.5%, P = 0.024) or when censoring it (90.6% vs. 96.1%, P = 0.026). Calculated glomerular filtration rate (43.8 vs. 58.3 ml/min, P < 0.001) and mean arterial blood pressure (101.3 vs. 97.1 mmHg, P = 0.047) were also improved with SRL‐ST. Differences in the incidences of biopsy‐proven acute rejection after randomization (6.5% vs. 10.2%, SRL‐CsA‐ST versus SRL‐ST, respectively) and mortality (7.9% vs. 4.7%) were not significant. SRL‐CsA‐ST‐treated patients had significantly higher incidences of adverse events generally associated with CsA, whereas those in the SRL‐ST group experienced greater frequencies of events commonly related to higher trough levels of SRL. In conclusion, early withdrawal of CsA from a SRL‐CsA‐ST regimen rapidly improves renal function and ultimately results in better graft survival.

Sirolimus‐Based Therapy Following Early Cyclosporine Withdrawal Provides Significantly Improved Renal Histology and Function at 3 Years

Graft function and histology are predictive of renal transplant survival. The Rapamune Maintenance Regimen study demonstrated that early cyclosporine (CsA) withdrawal from a sirolimus (SRL)‐CsA‐steroid (ST) regimen improved renal function and blood pressure. We report the protocol‐mandated biopsy findings from that study. Renal transplant patients (n = 430) receiving SRL‐CsA‐ST were randomized at 3 months after transplantation to remain on SRL‐CsA‐ST, or to have CsA withdrawn (SRL‐ST group). Protocol‐mandated biopsies were performed at engraftment and at 12 and 36 months. Two pathologists blindly evaluated 484 biopsies to obtain the Chronic Allograft Damage Index (CADI) scores. At 36 months among patients with serial biopsies (n = 63), the mean CADI score was significantly lower with SRL‐ST(4.70 vs. 3.20, p = 0.003), as was the mean tubular atrophy score (0.77 vs. 0.32, p < 0.001). All six components of the CADI score were numerically lower in SRL‐ST group; moreover, inflammation and the tubular atrophy scores decreased significantly in the SRL‐ST group between 12 and 36 months. The calculated glomerular filtration rate at 36 months was significantly better in the CsA‐withdrawal group (54.8 vs. 68.2 mL/min, p = 0.009). In conclusion, withdrawing CsA from the SRL‐CsA‐ST regimen resulted in improved renal histology and function.

Long-Term Benefits with Sirolimus-Based Therapy after Early Cyclosporine Withdrawal

Graft function at 6 or 12 mo is positively correlated with renal transplant survival. The 36-mo results of a study that tested whether withdrawing cyclosporine (CsA) from a sirolimus (SRL)-CsA-steroid (ST) regimen would affect renal graft survival are reported. Eligible patients (n = 430) who were receiving SRL-CsA-ST were randomly assigned at 3 mo to remain on SRL-CsA-ST or to have CsA withdrawn (SRL-ST group). At 36 mo, the calculated GFR was significantly better with SRL-ST (47.3 versus 59.4 ml/min; P < 0.001) as was the slope of the GFR (-3.6 versus 0.8 ml/min; P < 0.001). This was accompanied by growing trend for improved graft survival in the SRL-ST group (85.1% versus 91.2%, P = 0.052 at 36 mo; 81.4% versus 91.2%, P = 0.015 in a cumulative data analysis up to 54 mo), despite numerically more biopsy-proven acute rejections after randomization (5.6% versus 10.2%; P = 0.107). Lipid parameters were similar between groups, whereas both systolic and diastolic BP were significantly lower in the SRL-ST group. Investigator-reported hypertension, abnormal kidney function, edema, hyperuricemia, hyperkalemia, gingival hyperplasia, and Herpes zoster occurred significantly more often in SRL-CsA-ST patients. Abnormal liver function test results, hypokalemia, thrombocytopenia, and abnormal healing were reported significantly more often with SRL-ST. The discontinuation rate was significantly higher for SRL-CsA-ST (48% versus 38%; P = 0.041). In conclusion, withdrawing CsA from a SRL-CsA-ST regimen at 3 mo after transplantation resulted in long-term benefits for renal transplant recipients.

Evaluation of living renal donors: The current practice of US transplant centers

To examine practice patterns regarding how living donors are evaluated and selected in the U.S., a survey was sent to all 231 United Network of Organ Sharing (UNOS)-approved transplant centers. Respondents from 75% of centers completed the questionnaire, all of whom utilize living donors for renal transplantation. Although the use of living-unrelated donors is also widely accepted (in 92% of centers), only 31% of responding centers performed such transplants in 1992, indicating a discrepancy between acceptance and actual practice. Morbidity (0.23%) and mortality (0.03%) of kidney donation continue to be low. The long-term risk of renal insufficiency in kidney donors appears to be similar to, or lower than, that in the general population. There is substantial variability in how potential donors are evaluated and what they are told regarding the risk involved in renal donation. There is also variability in exclusion criteria such as the acceptance of older donors (>55 years old); those with borderline-to-mild hypertension, and those with borderline low glomerular filtration rate. Larger centers tended to be less rigid in their exclusion criteria compared with smaller centers. While our results indicate widespread acceptance and use of living donors, they also highlight the need for future studies to examine the efficacy of tests used in the evaluation process and to determine the long-term risks of renal donation.