INTRODUCTION

Nephrotoxicity , serious infectious, or malignancy risk , curtails tacrolimus use in PKT . However, based on potential antiviral and antitumoral actions of mTOR inhibitor drugs , low-dose tacrolimus associated with mTOR i (everolimus or sirolimus) regimes had been advocated. Hereby , we describe our 9-years experience with everolimus+tacrolimus.

PATIENTS AND METHODS

During 2008-2017, 24 children out of a total 102 PKT received manteinance treatment with tacrolimus and mTOR inhibitor after an initial IS regimen with basiliximab, tacrolimus , MMF and prednisolone. All cases (mean age 12 years old, range 1-17 years ) were first kidney transplant recipients of deceased donors with 4-6 miss-matches. Corticosteroids were withdrawn gradually after 6 months in all patients. Further, tacrolimus dose was reduced by 50% (target trough level 4-5ng/ml) and MMF replaced by mTORi after 8±2 months after transplantation due drug intolerance, BK or EBV PCR positivity or electively. Most children (20 out of a 24) were treated with everolimus (1.5 mg/m2/day; trough level 4-6 ng/ml).

RESULTS

There were no patient or graft loss during the 9-year period. Acute rejection was observed in 2 patients (8%), IFTA in 2 patients too (8%), at 3th and 5 th years of follow-up. Chronic humoral rejection was detected in one patient. Mean eGFR at 3, 6 and 9 years post-PKT was 71±25, 61±27, and 54+/-18 mL/min/1.73 m2, respectively). 2 patients had positive BK PCR (log 3-4 ) but did not suffer BK nephopathy , 2 patients were PCR EBV positive (log 4-5 ), whereas PCR CMV remained negative in all patients. Post-transplant lymphoproliferative disease (PTLD) was diagnosed in 3 patients (12%) (2 polyclonal,1monoclonal) and treated with temporary or definitive tacrolimus withdrawal (polyclonal, monoclonal), or chemotherapy R-COP (monoclonal) with good clinical outcome. After 9 years, 22 of 24 patients remain treated with tacrolimus plus mTORi , and functional grafts.

COMMENTS

[middot] Long term manteinance regimen with mTOR inhibitors and tacrolimus may be an advantegous therapy after pediatric KTX , in terms of less viral, neoplastic diseases or nephrotoxicity.

[middot] Non-inferiority and added advantages versus tacrolimus full-dose long-term treatment should be established in further studies , altough our limited experience is promisory.

CITATION INFORMATION: Vilalta R, Lara E, Madrid A, Muñoz M, Chocron S, Ariceta G. mTOR Inhibitor and Low-Dose Tacrolimus in Pediatric Kidney Transplant (PKT): 9-Years Data of a Bi-Therapy Treatment. Am J Transplant. 2017;17 (suppl 3).

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