Effect of Induction Therapy Dose on Survival in Abo-Incompatible Kidney Transplantation: A Network Meta-Analysis Using Recent Data.

Background: Rituximab is an essential induction immunosuppressant for ABO-incompatible kidney transplantation (KT) (ABOi-KT). However, studies on the optimal dose of rituximab are insufficient, and there are dosage differences between transplant centers and countries. Therefore, we conducted a study to determine the survival outcomes of patients receiving the most effective and safe dose of rituximab during ABOi-KT.

Methods: Studies on rituximab dose were divided into four groups: ABO compatible, 1) placebo, 2) rituximab 200 mg, 3) rituximab 200-500 mg, and 4) rituximab 500 mg. We searched the CENTRAL, MEDLINE, EMBASE, and Science Citation Index Expanded databases from 1970 to February 2022.9 . The inclusion criteria were adult patients (>18 years old). Reviews, observational studies, and clinical trials that did not clearly define outcomes or that did not have graft failure as an outcome were excluded. We performed direct and indirect network meta-analyses using Bayesian models and ranked different rituximab doses using a generation mixed treatment comparison (GeMTC) and Stata version 13. The NMA approach was evaluated using the GRADE framework, which specifies four levels of certainty for a given result: high, moderate, low, and very low. The outcomes included patient survival, graft failure, and bacterial and viral infections.

Results: Twenty-five trials, including 5,378 subjects, were divided into the following four groups: 1) placebo, 2) rituximab 200 mg, 3) rituximab 200-500 mg, and 4) rituximab 500 mg. We focused on survival outcomes according to the dose of rituximab when patients received induction therapy for ABOi-KT. The mortality rate was significantly lower in the ABO-compatible and rituximab 200 mg groups (odds ratio [OR] 0.27, 95% CrI: 0.071-0.91 and OR 0.14, 95% CrI 0.036-0.47), compared with that in the placebo group.

Conclusions: We found that low-dose rituximab in ABO-i KT was effective compared to the high-dose and placebo in maintaining the survival rate. However, large-scale and long-term data are necessary for further validation of our findings. Additionally, the use of smaller doses of rituximab will require further discussion.