Tacrolimus dosage requirements in lung transplant recipients receiving antifungal prophylaxis with voriconazole followed by itraconazole: a preliminary prospective study

Effect of Isavuconazonium Sulfate and Posaconazole Delayed Release Tablets on Tacrolimus Dose-to-Concentration Ratios

INTRODUCTION

Limited evidence exists on the effect of isavuconazonium sulfate and posaconazole delayed release tablets on tacrolimus dose-to-concentration ratios in lung transplant recipients.

PROJECT AIMS

The purpose of this evaluation was to assess the impact of novel triazoles on tacrolimus dose-to-concentration ratios.

DESIGN

This retrospective review included lung transplant recipient ≥18 years of age from January 1, 2017 to October 1, 2020 who received either posaconazole delayed release tablets or isavuconazonium sulfate for. A paired analysis evaluated outcomes pre-triazole and post-triazole initiation.

RESULTS

Forty-one patients met evaluation criteria for inclusion. A total of 34 of 41 patients received posaconazole delayed release tablets. Of these patients, 22 of 34 were transitioned from previous triazole to posaconazole delayed release tablets and experienced a 47% reduction in tacrolimus dose-to-concentration ratio. Twelve patients were newly initiated on posaconazole delayed release tablets and experienced a 50% reduction in tacrolimus dose-to-concentration ratios. Although not statistically significant, a 30% reduction in tacrolimus dose-to-concentration ratio was observed when transitioning to isavuconazonium sulfate from previous triazole therapy.

CONCLUSION

Limited data exists to provide guidance on tacrolimus dose adjustments with initiation and conversion of novel triazoles, however, this evaluation provides more knowledge on the drug interaction with novel triazoles and tacrolimus.

Targeted Aspergillus Prophylaxis With Voriconazole in Heart Transplant Patients: A Focus on the Interaction With Tacrolimus

Background: Voriconazole is a commonly used agent for the treatment and prophylaxis of invasive aspergillosis (IA) in heart transplant recipients. Complicating its use with this population is its significant interaction with the calcineurin inhibitors tacrolimus and cyclosporine. Most primary literature pertaining to this interaction focuses on use of voriconazole in allogeneic hematopoietic stem cell recipients. There is little information pertaining to the efficacy of voriconazole for IA prophylaxis or its effects on tacrolimus pharmacokinetics in heart transplant patients. Objective: Evaluate the use of voriconazole for invasive Aspergillus (IA) targeted prophylaxis in heart transplant recipients with a focus on the drug-drug interaction between voriconazole and tacrolimus and its impact on tacrolimus dose after discontinuation of voriconazole. Methods: This single-center, nonrandomized, retrospective, sequential study reviewed the use of targeted prophylaxis protocol in heart transplant recipients at Abbott Northwestern Hospital from January 2015 through May 2017. Results: Patients screened for targeted prophylaxis protocol from 2015 through 2017 had a 0% incidence of IA. This was in comparison to a 7% incidence of IA for a historical group of recipients from 2010 to 2014 prior to the use of the protocol. Additionally, patients on voriconazole needed on average a 67% reduction in tacrolimus dose (mg/kg/day) while on voriconazole compared with similar patients not on voriconazole to stay within the tacrolimus trough level protocol range. On discontinuation of voriconazole, a preemptive 100% tacrolimus dose increase resulted in 55% of tacrolimus trough levels within protocol range on first check. Overall, after 1-month post-voriconazole discontinuation, a 215% average increased tacrolimus dose was needed to maintain a level within the protocol trough range. Conclusion and Relevance: This study corroborates that targeted IA prophylaxis with oral voriconazole for up to 90 days is associated with a reduction in the incidence of IA in new heart transplant recipients. The pharmacokinetic analysis was able to provide more details on the effects of the interaction between voriconazole and tacrolimus in heart transplant recipients. Application of these data will better aid transplant centers to handle the effects of voriconazole discontinuation on patients on tacrolimus.

Effect of CYP3A5 and ABCB1 polymorphisms on the interaction between tacrolimus and itraconazole in patients with connective tissue disease

PURPOSE

The aim of this study was to investigate the effect of itraconazole (ITCZ), a potent inhibitor of CYP3A4 and P-glycoprotein, on the blood concentration 12 h after tacrolimus administration (C 12h) in relation to CYP3A5 6986A>G and ABCB1 3435C>T genotype status in patients with connective tissue disease (CTD).

METHODS

Eighty-one CTD patients taking tacrolimus (Prograf®) once daily at night (2100 hours) were enrolled in this study. Whole blood samples were collected 12 h after tacrolimus administration at steady state.

RESULTS

The dose-adjusted tacrolimus C 12h with or without ITCZ co-administration was significantly higher in patients with CYP3A5*3/*3 than in those with the CYP3A5*1 allele [CYP3A5 *1/*1 vs. *1/*3 vs. *3/*3 = 1.67 vs. 2.70 vs. 4.83 ng/mL/mg (P = 0.003) and 0.68 vs. 0.97 vs. 2.20 ng/mL/mg (P < 0.001), respectively], but differences were not observed for ABCB1 genotypes. However, there was no difference in the increase rate of the dose-adjusted C 12h of tacrolimus between CYP3A5 or ABCB1 genotypes (P = 0.378 and 0.259). On the other hand, reduction of the estimated glomerular filtration rate exhibited a correlation with the C 12h of tacrolimus after ITCZ co-administration (r = -0.482, P = 0.009).

CONCLUSIONS

In CYP3A5*3/*3 patients, because the metabolic pathway for tacrolimus occurs only through CYP3A4, the combination with ITCZ seems to lead to a higher risk of acute renal dysfunction. Therefore, we suggest that the target blood tacrolimus concentration be set as low as possible through dose-adjustment for patients with the CYP3A5*3/*3 allele.