Opportunistic Infections and Efficacy Following Conversion to Belatacept-Based Therapy after Kidney Transplantation: A French Multicenter Cohort.

Conversion from calcineurin-inhibitors (CNIs) to belatacept can help kidney-transplant (KT) recipients avoid CNI-related nephrotoxicity. The risk of associated opportunistic infections (OPIs) is ill-defined. We conducted a multicentric cohort study across 15 French KT-centers in a real-life setting. Between 07-2010 and 07-2019, 453 KT recipients were converted from CNI- to belatacept-based therapy at 19 [0.13-431] months post-transplantation. Most patients, i.e., 332 (79.3%), were converted after 6-months post-transplantation. Follow-up time after conversion was 20.1 +/- 13 months. OPIs developed in 42(9.3%) patients after 14 +/- 12 months post-conversion. Eight patients (19%) had two OPI episodes during follow-up. Incidences of CMV DNAemia and CMV disease were significantly higher in patients converted before 6-months post-KT compared to those converted later (i.e., 31.6% vs. 11.5%; p < 0.001; and 11.6% vs. 2.4%, p < 0.001, respectively). Cumulative incidence of OPIs was 6.5 OPIs/100 person-years. Incidence of CMV disease was 2.8/100 person-years, of pneumocystis pneumonia 1.6/100 person-years, and of aspergillosis 0.2/100 person-years. Multivariate analyses showed that estimated glomerular filtration (eGFR) < 25 mL/min/1.73 m ² at conversion was independently associated with OPIs (HR = 4.7 (2.2 - 10.3), p < 0.001). The incidence of EBV DNAemia was 17.3 events /100 person-years. At 1-year post-conversion, mean eGFR had significantly increased from 32.0 +/- 18 mL/min/1.73 m ² to 42.2 +/- 18 mL/min/1.73 m ² ( p < 0.0001). Conversion to belatacept is an effective strategy with a low infectious risk.