Model of population pharmacokinetics of cidofovir in immunocompromised children with cytomegalovirus and adenovirus infection.

Objectives To describe cidofovir pharmacokinetics and assess the link between concentration and safety/efficacy in children. Patients and methods An observational study was conducted in 13 immunocompromised children receiving cidofovir for adenovirus and/or cytomegalovirus infection. A population pharmacokinetic model was built and AUC0–24 was derived for each patient. Virological success was defined as a decrease of the viraemia by ≥1 log10 copies/mL within 15 days of cidofovir initiation. The association between AUC0–24 and virological success was assessed using a Wilcoxon test. An AUC0–24 cut-off value was determined using a Fisher’s exact test. Results Overall, 86 blood samples were analysed. A two-compartment model with first-order absorption and elimination best described the cidofovir data. Virological success (VS) was reached in 6/8 children with adenovirus viraemia and in 1/4 children with cytomegalovirus viraemia. Patients with VS displayed a non-significant higher median AUC0–24 compared with patients with virological failure: 48.6 (range 8.9–72.6) versus 19.1 (6.9–22.7) mg·h/L. Adenovirus-viraemic patients with an AUC0–24 value below 19.1 mg·h/L had a higher probability of treatment failure (P  = 0.03). Aviraemic children with stool and/or nasopharyngeal adenovirus carriage cleared the viral carriage within a month of cidofovir initiation. During treatment, 1/13 children developed a tubulopathy but none of them had an increase in creatininaemia. Conclusions Cidofovir appears safe and reasonably well tolerated and seemed to have efficacy in a subset of patients with adenovirus/cytomegalovirus infection. Therapeutic drug monitoring may be useful in children receiving cidofovir and, in the case of adenovirus infection, targeting an AUC0–24 above 19.1 mg·h/L could be associated with higher probability of virological success. [ABSTRACT FROM AUTHOR]