Rationale for monitoring cyclosporine concentration at 2 hours after administration in infants posttransplantation

Area of Science:

• Pediatric Transplantation
• Pharmacokinetics
• Immunosuppression Management

Background:

• Therapeutic drug monitoring is crucial for optimizing immunosuppression in pediatric transplant recipients.
• Cyclosporine (CsA) is a common immunosuppressant, but its narrow therapeutic index requires careful monitoring.
• Early post-liver transplant (OLT) period in infants presents unique pharmacokinetic challenges.

Purpose of the Study:

• To evaluate the utility of cyclosporine (CsA) trough (C0) and 2-hour post-dose (C2) concentrations in infants undergoing OLT.
• To determine if CsA C2 monitoring is justified in the early post-OLT period for young pediatric recipients.
• To assess the correlation between C0 and C2 concentrations and their ability to estimate CsA exposure.

Main Methods:

• Study included 17 infants (<2 years) receiving CsA (Neoral) after OLT.
• CsA concentrations were monitored at C0 (trough) and C2 (2-hour post-dose).
• Biopsy-proved acute rejection rates were assessed at 3 months post-OLT.

Main Results:

• A high rate of biopsy-proved acute rejection (65%) was observed at 3 months post-OLT.
• No significant correlation was found between C0 and C2 values in the early post-OLT period.
• Poor CsA absorption and significant interindividual variability in clearance were noted in most infants during the first two weeks.
• Neither C0 nor C2 alone adequately estimated CsA exposure in the early post-OLT phase.

Conclusions:

• CsA C2 monitoring is useful for identifying poor absorption but does not reflect drug clearance without simultaneous C0 measurement.
• Combined C0 and C2 monitoring, or AUC monitoring, is recommended for at least the first two weeks post-OLT in infants.
• Individualized monitoring strategies are essential to avoid over- or under-immunosuppression in this vulnerable population.