Therapeutic Drug Monitoring and Dose Adjustment of Posaconazole in Adult Patients with Acute Myeloid Leukemia: A Single-Center Experience

Abstract

Specific Aims: Evaluate serum posaconazole concentrations following dose adjustment in response to subtherapeutic serum concentrations. Determine optimal dose adjustment schema and identify toxicity with doses above 600 mg daily (e.g.: 200 mg per os three times daily). Methods: The health records were reviewed for 29 patients ≥ 18 years with acute myeloid leukemia over a four-year period. Participants initially received posaconazole 200 mg per os three times daily as prophylaxis and required at least one dose adjustment secondary to a subtherapeutic posaconazole serum concentration. Patients were stratified by posaconazole dosing following dose adjustment (A=200mg QID, B=300mg TID, C=400 mg TID, D=400 QID). Main Results: There was a statistically significant increase in posaconazole serum concentration in each group compared to baseline serum concentration, aside from group C (group A and B P<0.001, group C P=0.236, and group D P=0.0076). The majority of participants in 3 of the 4 groups reached therapeutic serum concentration (A=0.87, B=0.76, D=0.80) whereas group C had a serum posaconazole concentration on average below therapeutic range (0.51). There was no significant difference between the four groups in regards to renal function (p=0.35) or hepatic function (AST p=0.676, ALT p=0.877, total bilirubin p=0.097). Conclusion: A dose increase led to an increase in posaconazole serum concentration except for the dosing regimen of 400 mg three times daily. However, the study is limited by a small patient population, an unequal number of patients in each group, and potentially by poor absorption of posaconazole suspension. Further research is required to expand on these findings.