Evaluation of the pharmacokinetics of liposomal amphotericin B and analysis of the relationship between pharmacokinetics, efficacy and safety in patients with hematological diseases.

Introduction: This study aimed to identify factors responsible for changes in blood concentrations of a liposomal formulation of amphotericin B (AMPH-B, L-AMB) and analyze the relationships between blood concentrations and efficacy or toxicity.

Methods: L-AMB was administered to 30 patients being treated for hematological diseases. AMPH-B plasma concentrations were determined right before the initiation (C) and at the end (C) of infusion on at least 1 day, beginning on Day 3 of L-AMB treatment. The relationships of C divided by dose (C/D ratio) to body weight, age, hepatic function, renal function, serum albumin, C-reactive protein (CRP), response, hypokalemia, and renal impairment were evaluated.

Results: C/D ratio was not correlated with age, hepatic function, renal function, or serum albumin. Body weight adjusted C/D ratio was negatively correlated with CRP. C and C were compared between responders and non-responders, those with or without hypokalemia, and those with or without renal impairment. A higher C in patients with hypokalemia was the only significant difference seen.

Conclusions: The negative correlation between CRP and plasma concentrations was likely caused by higher distribution of L-AMB from the blood to infected tissue in patients with a greater degree of infection, with a resulting decrease in plasma concentrations. AMPH-B plasma concentrations were not related to response. Higher C of AMPH-B were observed in patients with hypokalemia, but no relationship between plasma concentration and renal toxicity was observed, suggesting that AMPH-B plasma concentrations appear to be minimally related to PD when used as L-AMB.