Comparison of intermittent intravenous tacrolimus to continuous tacrolimus in adult allogeneic stem cell transplant recipients.

Introduction: Initial continuous intravenous (CIV) tacrolimus (0.03 mg/kg/day based on ideal body weight [IBW]) has been favored for graft versus host disease (GVHD) prevention in allogeneic stem cell transplant patients due to the consistent, steady-state degree of immunosuppression; however, this method poses many logistical challenges. We implemented intermittent (IIV) tacrolimus at a starting dose of 0.015 mg/kg IBW twice daily over 4 h. To our knowledge this is the first retrospective comparison of CIV to IIV tacrolimus. Objectives: The primary objective was to evaluate the safety of IIV tacrolimus in comparison to CIV with respect to nephrotoxicity and neurotoxicity. The secondary objectives were to compare the incidence of grade II-IV acute GVHD (aGVHD) and chronic GVHD (cGVHD) at day +180, outcomes including relapse and overall survival, cell engraftment, and reactivation of cytomegalovirus and Epstein-Barr virus. Methods: This retrospective, single-center review evaluated adults who received an allogeneic stem cell transplant patients between January 1, 2020, and December 31, 2022. Results: Fifty-one unique patients were eligible for evaluation - 28 in the IIV cohort and 23 in the CIV group. The number of patients who developed nephrotoxicity and neurotoxicity were comparable between groups with no significant differences noted. No severe neurotoxicity was identified in either population. Secondary objectives revealed no significant difference in GVHD incidence or survival outcomes. Conclusion: IIV tacrolimus is comparable to CIV in terms of safety while also maintaining similar outcomes at day +180. IIV is a safe and feasible alternative to CIV in adult allogeneic stem cell transplant recipients.