Immunosuppression switching from tacrolimus to sirolimus improves renal function in adult intestinal transplant recipients

Introduction: There is a 40% decline in renal function in the first 3 months post-intestinal transplant even with renal sparing strategies. This retrospective, single centre study of the renal function of adult intestinal transplant recipients describes outcomes after switching from tacrolimus to sirolimus. Methods: Baseline characteristics, renal function and complications related to immunosuppression switch were collected. Recipients were included if they had been switched to sirolimus based immunosuppression for at least six months. Adverse outcomes were collected. Results: There were 129 adult intestinal transplants from Dec 2007 to April 2022 with 45 recipients meeting the inclusion criteria. 35 of the 45 were colon containing grafts in 14 multivisceral transplant MVT, 9 liver and small bowel LSB, 6 modified multivisceral transplant MMVT and 16 small bowel SBT patients. Follow up period ranged from 12.1 to 184.1 months (median 66.2 months). The sirolimus switch occurred between 2.1 months and 146 months post-transplant (median 12.23). At the time of switching, 16 recipients had an end colostomy, 12 had an end ileostomy, 3 had a Bishop-Koop stoma and 14 were in continuity. Median eGFR at transplant was 100 ml/min/1.73m2. The indication for switching was predominantly renal impairment (38 patients), the rest for other reasons such as intolerance to antimetabolites, anti-tumour properties and side effects of other immunosuppressants. Before switching 5 patients had CKD stage 1 and 2, 26 patients had Stage 3, 10 patients had Stage 4 and 5. At 12 months after switching, 9 patients had Stage 1 and 2, 17 patients had Stage 3 and only 2 patients had Stage 4. This represented a change in median eGFR from 36 to 52ml/min/1.73m2 at 60 days post switch which remained stable thereafter. Adverse events included acute cellular rejection resulting in graft loss in 3 recipients. Four had severe rejection and 2 moderate. Six recipients described symptomatic peripheral oedema and 2 had an albumin/creatinine ratio >100. Conclusion: In this small, single centre, adult cohort we have demonstrated a median increase in eGFR of 16ml/min/1.73m2, observed 60 days post switching. Significant events included rejection and graft loss and intensive monitoring during this time is critical.