The pharmacokinetics of caspofungin are expected to be different in ICU patients compared to non-ICU patients. The investigators will determine caspofungin concentrations in 20 ICU patients, who will get caspofungin as standard care.

Full PK curves will be taken on day 3 and a limited PK curve on day 7, trough levels will be taken daily.

The pharmacokinetics of caspofungin are expected to be different in ICU patients compared to non-ICU patients and healthy volunteers due to underlying disease(s). Therefore, extrapolation of data from healthy volunteers and non-ICU patients is not possible.

To be able to include 20 patients within the study duration, a multi-centre approach is necessary.

Patients will receive standard care, as stated in the SPC or according to local protocols. Blood sampling for PK analysis will be retrieved through a central venous catheter. Approximately 60mL will be drawn in total for this study. Patients will be monitored daily during the treatment period for adverse events of the study drug.

Although steady state of caspofungin will be achieved after approximately 14 days of treatment, full PK curves will be taken on day 3. As probably not all patients included will be treated with caspofungin for 14 days, taking full PK curves on day 14 is considered not feasible. These two moments of PK analysis will enable the determination steady state and enable the determination of intra-individual variability.

Inclusion Criteria:

• Patient is admitted to an ICU
• Subject is at least 18 and not older than 65 years of age on the day of the first dosing
• Subject has been treated with caspofungin for a maximum of two days before enrolment in this trial
• Is managed with a central venous catheter

Exclusion Criteria:

• Is known to be hypersensitive to echinocandin antifungal agents
• Documented history of sensitivity to medicinal products or excipients similar to those found in the caspofungin preparation
• Positive HIV test or hepatitis B or C test
• History of QT time prolongation
• History of or current abuse of drugs, alcohol or solvents
• Has previously participated in this trial

intensive care patients with invasive fungal infection