Posaconazole therapeutic drug monitoring in the real-life setting: a single-center experience and review of the literature.

STUDY OBJECTIVE

To evaluate the incidence of posaconazole serum levels below 700 μg/L, the rate of breakthrough infections during posaconazole prophylaxis, and factors influencing posaconazole exposure in daily clinical practice.

DESIGN

Prospective observational study and review of the literature.

SETTING

Hematology and oncology department in a tertiary care academic medical center.

PATIENTS

A total of 31 patients with hematologic diseases: 27 received posaconazole prophylaxis and 4 received posaconazole therapy.

MEASUREMENTS AND MAIN RESULTS

We analyzed 187 posaconazole serum levels from 31 patients (median of five posaconazole levels per patient; range 1-16). The analyses revealed that 80 of 187 levels (43%) were below 700 μg/L, and 68% of patients were found to have at least one measured level below this threshold. Breakthrough invasive fungal infections categorized as probable or possible infections occurred in 4 of 27 patients (15%) receiving the drug as prophylaxis. A multivariate analysis, accounting for repeated measurements per patient, revealed that age (p=0.02) and mucositis (p=0.04) were associated with significantly reduced posaconazole serum levels. A review of the current literature on posaconazole therapeutic drug monitoring data from real-world studies is presented as an overview table, highlighting the frequency of patients with inadequate posaconazole exposure and heterogeneity of factors influencing posaconazole levels.

CONCLUSION

Therapeutic drug monitoring of posaconazole is an important tool of therapy optimization because oral posaconazole suspension shows unreliable absorption rates and exposure.