Pharmacokinetics and safety of extemporaneously compounded valacyclovir oral suspension in pediatric patients from 1 month through 11 years of age.

BACKGROUND: Valacyclovir provides enhanced acyclovir bioavailability in adults, but limited data are available in children. METHODS: Children 1 month through 5 years of age with or at risk for herpesvirus infection received a single 25 mg/kg dose of extemporaneously compounded valacyclovir oral suspension (n = 57), whereas children 1 through 11 years of age received 10 mg/kg valacyclovir oral suspension twice daily for 3-5 days (herpes simplex virus infection) (n = 28) or 20 mg/kg 3 times daily for 5 days (varicella-zoster virus infection) (n = 27). Blood samples for pharmacokinetic analysis were collected during the 6 h after the first dose. Safety was monitored throughout the studies. RESULTS: Dose proportionality in the maximum observed concentration (C(max)) of acyclovir and the area under the concentration-time curve from time zero extrapolated to infinity (AUC(0-infinity)) existed across the 10 to 20 mg/kg valacyclovir dose range. For children 2 through 5 years of age, an increase in dose from 20 to 25 mg/kg resulted in near doubling of the C(max) and AUC(0-infinity). Among infants 1 through 2 months of age receiving 25 mg/kg, the mean AUC(0-infinity) and C(max) were higher ( approximately 60% and 30%, respectively) than those among older infants and children receiving the same dose. Valacyclovir oral suspension was well tolerated. No clinically significant trends were noted in clinical chemical, hematologic, or urinalysis values from screening to follow-up. CONCLUSIONS: Among children 3 months through 11 years of age, the 20 mg/kg dose of this formulation of valacyclovir oral suspension produces favorable acyclovir blood concentrations and is well tolerated. A dosing recommendation cannot be made for infants <3 months of age because of decreased clearance in this age group. Trial registration. ClinicalTrials.gov identifier: NCT00297206 .

An international, randomized, double-blind, placebo-controlled, study of valacyclovir for the suppression of herpes simplex virus type 2 genital herpes in newly diagnosed patients.

BACKGROUND: Antiviral suppressive therapy of genital herpes is often initiated based on the established pattern of recurrences in an individual. Because most persons with first episode herpes simplex virus type 2 (HSV-2) infection experience recurrences and because viral shedding occurs frequently in the first year after infection, we examined the strategy of initiating suppressive therapy shortly after diagnosis of genital HSV-2 infection. SUBJECTS AND METHODS: From June 16, 2004 to July 26, 2006, 384 subjects from 74 sites in the United States, Canada, Argentina, Brazil, and Chile who were newly diagnosed with a first recognized episode of genital herpes at the time of the screening visit or within 3 months before the screening visit were randomized (2:1) to receive valacyclovir 1 g once daily or placebo for 24 weeks. Subjects were instructed to return to clinic during suspected genital herpes outbreaks for clinician confirmation of recurrences. RESULTS: Valacyclovir significantly prolonged the time to first recurrence of HSV-2 genital herpes in newly diagnosed subjects compared with placebo, with approximately 43% of subjects on placebo and 71% of subjects on valacyclovir recurrence-free at 24 weeks (P <0.001). Valacyclovir significantly reduced the mean number of genital HSV-2 recurrences per month occurring during the 24-week study period (0.11 for valacyclovir, 0.48 for placebo, P <0.001). Adverse events were comparable in the valacyclovir and placebo arms. CONCLUSION: Valacyclovir 1 g once daily administered for 24 weeks was well-tolerated and effective in suppressing genital herpes recurrences in immunocompetent newly diagnosed persons without an established recurrence pattern.

Effect of valacyclovir on viral shedding in immunocompetent patients with recurrent herpes simplex virus 2 genital herpes: a US-based randomized, double-blind, placebo-controlled clinical trial.

OBJECTIVE: To determine the efficacy of daily suppressive therapy with a 1-g dose of valacyclovir in reducing total (clinical and subclinical) herpes simplex virus 2 (HSV-2) shedding compared with placebo in Immunocompetent patients diagnosed as having recurrent HSV-2 genital herpes. PATIENTS AND METHODS: From June 18, 2004, to December 17, 2004, patients from 27 US sites with a history of 6 or more genital herpes recurrences per year were randomized in a 3:1 ratio to receive 1 g/d of valacyclovir or placebo. During the double-blind suppressive therapy, patients were provided with the study drug (500-mg valacyclovir caplets or matching placebo) and Instructed to take 2 caplets once daily without regard to meals for 60 days. Daily genital and anal or rectal swabs were self-collected during the 60-day study period for evaluation of HSV-2 viral shedding as determined by quantitative type-specific polymerase chain reaction assay. RESULTS: One hundred fifty-two patients were randomized into this study, 43 to placebo and 109 to 1 g/d of valacyclovir. A total of 134 completed the study (40 placebo [93%], 94 valacyclovir [86%]), and 18 prematurely withdrew (3 placebo [7%], 15 valacyclovir [14%]). Valacyclovir significantly reduced the percentage of days with total (clinical and subclinical) HSV-2 shedding throughout 60 days compared with placebo. In the intent-to-treat population, a 71% reduction in total shedding (P < .001), a 58% reduction in subclinical shedding (P < .001), and a 64% reduction in clinical shedding (P = .01) were observed. Valacyclovir was not associated with any significant toxic effects compared with placebo. CONCLUSION: This study demonstrated that 1 g/d of valacyclovir administered for 60 days was generally well tolerated and was an effective suppressive therapy that significantly reduced total (clinical and subclinical) HSV-2 shedding compared with placebo in immunocompetent patients diagnosed as having recurrent HSV-2 genital herpes.