Introduction

After kidney transplantation, long-term immunosuppression with calcineurin inhibitors (CNIs) or mTOR inhibitors (mTORi) leads to adverse effects, such as nephrotoxicity and proteinuria. Currently, available data support use of belatacept as rescue therapy in patients with suboptimal allograft function and/or proteinuria.

Patients and methods

We conducted a retrospective monocentric cohort study including all kidney allograft recipients (>18 years, EBV +) followed from Dec/2012 and Dec/2015 after conversion from CNI-based immunosuppressive regimen to belatacept at any time after transplant.

Primary objective was a 20% improvement of median estimated glomerular filtration rate (eGFR) 12-months after conversion. Secondary objectives were (i) identify the main reasons of conversion, (ii) incidence of acute rejection after conversion, (iii) incidence of infectious complications after conversion, (iv) length of Belatacept treatment.

Results

73 patients with conversion were included in this cohort from Dec/2012 and Dec/2015. Conversion median delay after transplant was 10 (2-26) months. At the time of conversion, median eGFR was 25 (19-36) ml/min/1.73m² and median proteinuria ratio was 42 (17-103) mg/mmol. To analyze the primary objective, we considered the 49 patients with 12-months follow-up. eGFR improved significantly in 22 (45%) recipients, remained stable in 20 (41%) and decreased significantly in 7 (14%). At the end of follow-up (19 (9-31) months), eGFR increased significantly to 31 (22-44) ml/min/1.73m² (P=0.02) and proteinuria ratio was stable at 27 (13-107) mg/mmol (P=0.65).

Main reasons of switch were histological chronic lesions associated with non-optimal kidney allograft function (N=34 (45%)), delayed graft function (N=27 (36%)) and thrombotic microangiopathy (N=9 (12%)).

Incidence of acute rejection after switch was 8% (N=6).

After the switch, infectious complications observed were resistant CMV viremia (N=3; 4%), opportunistic infections (N=3; 4%) and BK viremia (N=1; 1.5%). Median length of belatacept treatment was 19 (9-31) months.

Conclusion

Belatacept as rescue therapy is safe and truly effective with almost 50% of significant improvement of eGFR 12-months after switch, low incidence of rejection and infectious complications.

CITATION INFORMATION: Matignon M., Dudreuilh C., Rémy P., Desvaux D., Grimbert P. Effect and Reasons of Rescue Switch to Belatacept among 73 Calcineurin-Inhibitors Treated Kidney Allograft Recipients – A Three Years Retrospective Cohort, Single Center Study Am J Transplant. 2017;17 (suppl 3).

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