Strategies for Liver Transplantation Tolerance.

Liver transplant (LT) recipients require life-long immunosuppression (IS) therapy to preserve allograft function. The risks of chronic IS include an increased frequency of malignancy, infection, renal impairment, and other systemic toxicities. Despite advances in IS, long-term LT outcomes have not been improved over the past three decades. Standard-of-care (SoC) therapy can, in rare cases, lead to development of operational tolerance that permits safe withdrawal of maintenance IS. However, successful IS withdrawal cannot be reliably predicted and, in current prospective studies, is attempted several years after the transplant procedure, after considerable exposure to the cumulative burden of maintenance therapy. A recent pilot clinical trial in liver tolerance induction demonstrated that peri-transplant immunomodulation, using a regulatory T-cell (Treg) approach, can reduce donor-specific alloreactivity and allow early IS withdrawal. Herein we review protocols for active tolerance induction in liver transplantation, with a focus on identifying tolerogenic cell populations, as well as barriers to tolerance. In addition, we propose the use of novel IS agents to promote immunomodulatory mechanisms favoring tolerance. With numerous IS withdrawal trials underway, improved monitoring and use of novel immunomodulatory strategies will help provide the necessary knowledge to establish an active liver tolerance induction protocol for widespread use.

De novo therapy with everolimus and reduced-exposure cyclosporine following pediatric kidney transplantation: a prospective, multicenter, 12-month study.

Prospective data regarding the de novo use of everolimus following kidney transplantation in children are sparse. In a prospective, 12-month, single-arm, open-label study, pediatric kidney transplant patients received everolimus (target trough concentration ≥3 ng/mL) with reduced-exposure CsA and corticosteroids, with or without basiliximab induction. Sixteen of the 18 patients completed the study on-treatment. Age range was 2-16 yr (mean 10.9 yr); eight patients received a living donor graft. Mean (s.d.) everolimus level was 7.4 (3.1) ng/mL during the first 12 months post-transplant. There were no cases of BPAR, graft loss, or death during the study. Protocol biopsies were performed at month 12 in seven patients, with subclinical (untreated) acute rejection diagnosed in one case. Mean (s.d.) estimated GFR (Schwartz formula) was 98 (34) mL/min/1.73 m(2) at month 12. Three patients experienced one or more serious adverse events with a suspected relation to study medication. One patient discontinued study medication due to post-transplant lymphoproliferative disease (5.6%). Everolimus with reduced-dose CsA and corticosteroids achieved good efficacy and renal function and was well tolerated in this small cohort of pediatric kidney transplant patients. Controlled trials are required to answer remaining questions about the optimal use of everolimus in this setting.

Efficacy and safety of SBR759, a novel calcium-free, iron(III)-based phosphate binder, in Asian patients undergoing hemodialysis: A 12-week, randomized, open-label, dose-titration study versus sevelamer hydrochloride.

AIM: SBR759 is a calcium-free, polymeric, iron(III)-based oral phosphate binder, in development for the treatment of hyperphosphatemia. The efficacy and safety of SBR759 was compared with sevelamer hydrochloride in chronic kidney dialysis patients on hemodialysis. METHODS: Japanese and Taiwanese hyperphosphatemic patients who were on hemodialysis (n = 203) received starting doses of 3.0 or 4.5 g/day SBR759 or 2.4 or 4.8 g/day sevelamer-hydrochloride (HCl) based on baseline phosphate levels. Daily doses were up-titrated every 2 weeks to reach the Kidney Disease Outcomes Quality Initiative (K/DOQI) recommended target serum phosphate concentration ≤1.7 mmol/L. The key endpoints were proportion of patients achieving target serum phosphate and the safety at week 12. RESULTS: SBR759 showed a superior phosphate response at week 12 compared with sevelamer-HCl (83% vs 54% patients; P < 0.0001). Mean serum calcium concentrations were unaffected by either treatment. Similar incidences of adverse events and serious adverse events were seen with SBR759 and sevelamer-HCl (90.3% vs 94.1% and 5.2% vs 4.4%, respectively), but overall discontinuation rates were lower with SBR759 (11.9% vs 20.6%). The proportion of patients experiencing gastrointestinal disorders was lower in SBR759 versus sevelamer-HCl. No treatment-related serious adverse events were reported. CONCLUSIONS: SBR759 showed superior phosphate control with a favorable tolerability profile compared to sevelamer-HCl in hemodialysis patients.

Multicenter trial of everolimus in pediatric renal transplant recipients: results at three year.

There are few prospective clinical trials of mTOR inhibitors (or proliferation signal inhibitors) combined with CNI inhibitors in de novo pediatric renal transplantation. Results reported here are from a multicenter, open-label study in de novo pediatric renal transplant patients (

Everolimus with reduced cyclosporine versus MMF with standard cyclosporine in de novo heart transplant recipients.

BACKGROUND: Pharmacokinetic modeling supports trough monitoring of everolimus, but prospective data comparing this approach versus mycophenolate mofetil (MMF) in de novo cardiac transplant recipients are currently unavailable. METHODS: In a 12-month multicenter open-label study, cardiac transplant patients received everolimus (trough level 3-8 ng/mL) with reduced cyclosporine A (CsA) or MMF (3 g/day) with standard CsA, both with corticosteroids+/-induction therapy. RESULTS: In total, 176 patients were randomized (everolimus 92, MMF 84). Mean creatinine clearance was 72.5+/-27.9 and 76.8+/-32.1 mL/min at baseline, 65.4+/-24.7 and 72.2+/-26.2 mL/min at month 6, and 68.7+/-27.7 and 71.8+/-29.8 mL/min at month 12 with everolimus and MMF, respectively. The primary endpoint was not met since calculated CrCl at month 6 posttransplant was 6.9 mL/min lower with everolimus, exceeding the predefined margin of 6 mL/min. However, by month 12 the between-group difference had narrowed versus baseline (3.1 mL/min). All efficacy endpoints were noninferior for everolimus versus MMF. The 12-month incidence of biopsy-proven acute rejection International Heart and Lung Transplantation grade more than or equal to 3A was 21 of 92 (22.8%) with everolimus and 25 of 84 (29.8%) with MMF. Adverse events were consistent with class effects including less-frequent cytomegalovirus infection with everolimus (4 [4.4%]) than MMF (14 [16.9%], P=0.01). CONCLUSION: Concentration-controlled everolimus with reduced CsA results in similar renal function and equivalent efficacy compared with MMF with standard CsA at 12 months after cardiac transplantation.