Evaluation of the Pharmacokinetics (PK) and Pharmacodymamics (PD) of Ganciclovir (GCV) in Premature Infants Receiving Treatment for Cytomegalorivus (CMV) Infection

This is an open-label, multi-center, clinical sampling study to assess ganciclovir pharmacokinetics and pharmacodynamics in premature infants. Only those subjects who receive ganciclovir for clinical reasons will be enrolled. The decision to initiate ganciclovir therapy will be made by the attending physician based upon his/her clinical decision to treat virologically-confirmed CMV infection; infants receiving such therapy and meeting entry criteria will then be eligible for this study. Therefore, ganciclovir will not provided under this protocol. Subjects meeting enrollment criteria will be entered into this clinical trial. Subjects will be stratified by gestational age and by chronologic age as follows: 1) ≤ 27 weeks 6 days gestational age at birth and ≤ 30 days chronologic age at study enrollment; 2) ≤ 27 weeks 6 days gestational age at birth and \> 30 days chronologic age at study enrollment; 3) ≥ 28 weeks 0 days gestational age at birth and ≤ 30 days chronologic age at study enrollment; 4) ≥ 28 weeks 0 days gestational age at birth and \> 30 days chronologic age at study enrollment. Eight subjects will enroll in each of the four groups, for a total sample size of 32 subjects. Subjects in each cohort with inadequate pharmacokinetic data for analysis (e.g., due to dropping out of the study before PK assessments are performed, or blood sampling obtained but is inadequate for analysis) will be replaced and will not count toward the total of eight subjects in each of the four groups. Additionally, enrollment of an additional 2-3 subjects may be allowed for operational reasons. A full pharmacokinetic profile will be obtained with one of the ganciclovir doses received after enrollment. PK assessments will be obtained after the subject has received study assessment dose 3, 4, 5, 6, 7, or 8 of intravenous ganciclovir. Specimens will be shipped for processing at that time. The pharmacokinetic data will then be provided to the study site, including the area under curve (AUC) and clearance (CL) values for information purposes. Duration of intravenous ganciclovir therapy is at the discretion of the treating physician and will not be dictated by the research protocol. Both whole blood for CMV polymerase chain reaction (PCR) and urine for CMV detection will be obtained once in each study period as long as the subject is receiving intravenous ganciclovir therapy. These specimens will be used to determine blood viral load and ganciclovir resistance. Since ganciclovir is a renally excreted drug, serum creatinine will be drawn for the research protocol on the day that the ganciclovir pharmacokinetic specimens are obtained in order to calculate creatinine clearance using a method such as the modified Schwartz formula, and thus correlate ganciclovir clearance with renal function. Otherwise, data from hematology assessments (WBC count and differential, hemoglobin, platelet count) and from chemistry labs (serum creatinine, aspartate aminotransferase (AST) , and alanine aminotransferase (ALT) will be recorded on the study case report forms during each study period if they are being obtained for clinical reasons, but will not be drawn only for the purposes of the study. Ganciclovir dosing information (mg/dose, dosing interval, and patient weight) will be recorded on the day of the pharmacokinetic blood draws, and weekly from Period 1 through Period 7 as long as the subject is receiving intravenous ganciclovir therapy. If the patient continues to receive intravenous ganciclovir from Study Assessment Day 18 through Study Assessment Day 24 (Period 4), a second PK assessment may be performed at the request of the treating physician if the subject weighs 575 grams or more at the time of specimen collection.