Improved Induction and Maintenance Immunosuppression in Kidney Transplantation

Prospective, Randomized 2 x 2 Factorial Trial of Rabbit Anti-thymocyte Globulin Induction (Single vs. Alternate Day Administration) at Renal Transplantation, With Delayed Calcineurin-inhibitor Withdrawal vs. Minimization

This 2 x 2 sequential factorial study evaluates two potential improvements to the standard immunosuppression regimen used at the investigators' institution to prevent rejection of transplanted kidneys. These two potential improvements are each applied in sequence to half of the study patients, creating 4 study arms; the other half receive the standard treatment. The two potential improvements are: Administering the immunosuppression induction agent rATG ("rabbit anti-thymocyte globulin") in a single dose at the time of transplantation, instead of in the usual series of 4 smaller doses over 6 days. After 6 months, modifying the maintenance immunosuppression used to prevent rejection by replacing the drug tacrolimus with mycophenolate mofetil (MMF). The two interventions, spaced sequentially six months apart, enable independent analysis of the two treatments so long as it can be shown that there is no synergistic interaction between them.

The two treatment innovations in this study of immunosuppression in kidney transplantation are aimed at making the transplanted kidney function sooner and last longer than is usual with standard immunosuppression regimens, but without increasing the likelihood of rejection. The first innovation, delivering the induction agent rATG in a single large dose rather than as a series of smaller doses over 6-8 days, is expected to produce better graft function right away, possibly by reducing some of the injury to the kidney that accompanies the restoration of blood flow during transplantation ("reperfusion injury"). Some evidence has been developed by investigators elsewhere to suggest this will happen. The second innovation, replacing tacrolimus with MMF after 6 months, is intended to eliminate a well-established major cause of ongoing toxic damage to the kidney. While tacrolimus does a good job of preventing rejection, the cost in continuing toxic injury to the kidney is high, leading inevitably to eventual graft failure, the inability of the transplanted kidney to continue filtering the blood and making adequate volumes of high-quality urine.

Kidney transplant recipients given a single large dose of rabbit anti-thymocyte globulin (rATG) and maintained on tacrolimus and sirolimus for chronic immunosuppression.

Kidney transplant recipients given 4 small doses of rabbit anti-thymocyte globulin (rATG) and maintained on tacrolimus and sirolimus for chronic immunosuppression.

Kidney transplant recipients given a single large dose of rabbit anti-thymocyte globulin (rATG) and maintained on tacrolimus and sirolimus for chronic immunosuppression until tacrolimus is replaced with mycophenolate mofetil after about 6 months.

Kidney transplant recipients given 4 small doses of rabbit anti-thymocyte globulin (rATG) and maintained on tacrolimus and sirolimus for chronic immunosuppression until tacrolimus is replaced with mycophenolate mofetil after about 6 months.

A single 6 mg/kg dose of rATG administered intravenously over 24 hours, beginning before kidney transplantation. Administration of the drug is begun as early as practical, usually after general anesthesia has been established but before surgery has started. The rATG is therefore administered for about two hours before blood flow is restored to the kidney undergoing transplantation.

Patients are switched approximately 6 months after kidney transplantation from maintenance immunosuppression with tacrolimus and sirolimus to maintenance with mycophenolate mofetil and sirolimus. The drug is administered orally, taken daily, with dose adjusted in proportion to measured blood levels, and is required indefinitely to prevent rejection of the transplanted kidney.

6 mg/kg rabbit anti-thymocyte globulin delivered in 4 doses of 1.5 mg/kg each, the first administered at the time of kidney transplantation. Subsequent doses are administered on days 2, 4, and 6.

Oral maintenance immunosuppressant administered daily, dose adjusted according to measured serum trough levels, continued indefinitely to prevent kidney rejection

Oral maintenance immunosuppressant, taken daily, dose adjusted to maintain target blood trough levels, required indefinitely to prevent kidney rejection.

Chronic Allograft Nephropathy (Cumulative Calcineurin-inhibitor Nephrotoxicity/Transplant Nephropathy) Per Protocol Surveillance Kidney Biopsies (Banff Grading Criteria).

Protocol kidney biopsies collected at approximately 12 and 24 months were scored by a transplant renal pathologist blinded to treatment group assignment for evidence of rejection, BK virus nephropathy, antibody-mediated rejection, recurrent disease, inflammation, and Banff 2005 categories of chronic renal injury. Chronic injury categories were arteriolar hyaline thickening (ah), allograft glomerulopathy (cg), interstitial fibrosis (ci), tubular atrophy (ct), and vascular fibrous intimal thickening (cv). Severity scores within each category could be 0 (<5%; none or minimal), 1 (>5% - <25%; mild), 2 (>25% - <50%, moderate), or 3 (>50%, severe). The proportions of patients in each severity grade (0, 1, 2, and 3) for both the individual categories and a composite were compared using Fisher's exact test.

Calculated Glomerular Filtration Rate (GFR) by using the abbreviated MDRD (aMDRD) formula and patient serum creatinine and demographic data; averaged values from months four through 24.

Number of events: cytomegalovirus (CMV) disease, opportunistic infections (bacteremia, abscess, pneumonia, fungal), Post-transplantation Lymphoproliferative Disorder (PTLD), wound healing problems within 30 days, and lymphoceles.

Requirement for Additional Immunosuppression (Such as Corticosteroids, Antimetabolites or Other Immunosuppressive Agents)

Acute Tubular Necrosis (ATN) Rate, Defined as the Requirement for Dialysis Within 7 Days Post-transplantation.

Inclusion Criteria: Primary renal transplant recipient for end-stage renal disease Exclusion Criteria: Recipient age < 18 years or > 65 years Previous history of CMV disease Hepatitis B and C recipients Primary disease states that require steroids for immunosuppression Re-transplant with immunological cause of renal or pancreas loss Non heart beating donors Recipient of pediatric en bloc kidneys Recipient with a Panel Reactive Antibody (PRA) score >75% Patients who have received 3 or more prior transplants, excluding pancreas Patients who are past recipients of other solid organ transplants Previous history of BK virus Previous treatment with Thymoglobulin Allergy to rabbits Simultaneous Kidney/Pancreas transplantation

Miles CD, Skorupa JY, Sandoz JP, Rigley TH, Nielsen KJ, Stevens RB. Albuminuria after renal transplantation: maintenance with sirolimus/low-dose tacrolimus vs. mycophenolate mofetil/high-dose tacrolimus. Clin Transplant. 2011 Nov-Dec;25(6):898-904. doi: 10.1111/j.1399-0012.2010.01353.x. Epub 2010 Nov 16.

Stevens RB. Modern approaches to combining sirolimus with calcineurin inhibitors. Transplant Proc. 2008 Dec;40(10 Suppl):S21-4. doi: 10.1016/j.transproceed.2008.10.012.

Sulanc E, Lane JT, Puumala SE, Groggel GC, Wrenshall LE, Stevens RB. New-onset diabetes after kidney transplantation: an application of 2003 International Guidelines. Transplantation. 2005 Oct 15;80(7):945-52. doi: 10.1097/01.tp.0000176482.63122.03.

Stevens RB, Foster KW, Miles CD, Lane JT, Kalil AC, Florescu DF, Sandoz JP, Rigley TH, Nielsen KJ, Skorupa JY, Kellogg AM, Malik T, Wrenshall LE. A randomized 2x2 factorial trial, part 1: single-dose rabbit antithymocyte globulin induction may improve renal transplantation outcomes. Transplantation. 2015 Jan;99(1):197-209. doi: 10.1097/TP.0000000000000250.

Stevens RB, Lane JT, Boerner BP, Miles CD, Rigley TH, Sandoz JP, Nielsen KJ, Skorupa JY, Skorupa AJ, Kaplan B, Wrenshall LE. Single-dose rATG induction at renal transplantation: superior renal function and glucoregulation with less hypomagnesemia. Clin Transplant. 2012 Jan-Feb;26(1):123-32. doi: 10.1111/j.1399-0012.2011.01425.x. Epub 2011 Mar 14.

Snow MH, Cannella AC, Stevens RB, Mikuls TR. Presumptive serum sickness as a complication of rabbit-derived antithymocyte globulin immunosuppression. Arthritis Rheum. 2009 Sep 15;61(9):1271-4. doi: 10.1002/art.24788. No abstract available.

Stevens RB, Mercer DF, Grant WJ, Freifeld AG, Lane JT, Groggel GC, Rigley TH, Nielsen KJ, Henning ME, Skorupa JY, Skorupa AJ, Christensen KA, Sandoz JP, Kellogg AM, Langnas AN, Wrenshall LE. Randomized trial of single-dose versus divided-dose rabbit anti-thymocyte globulin induction in renal transplantation: an interim report. Transplantation. 2008 May 27;85(10):1391-9. doi: 10.1097/TP.0b013e3181722fad.

Stevens RB, Foster KW, Miles CD, Kalil AC, Florescu DF, Sandoz JP, Rigley TH, Malik T, Wrenshall LE. A Randomized 2x2 Factorial Clinical Trial of Renal Transplantation: Steroid-Free Maintenance Immunosuppression with Calcineurin Inhibitor Withdrawal after Six Months Associates with Improved Renal Function and Reduced Chronic Histopathology. PLoS One. 2015 Oct 14;10(10):e0139247. doi: 10.1371/journal.pone.0139247. eCollection 2015.