WARNINGS
Included as part of the PRECAUTIONS section.
PRECAUTIONS
General
DENAVIR should only be used on herpes labialis on the
lips and face. Because no data are available, application to human mucous
membranes is not recommended. Particular care should be taken to avoid
application in or near the eyes since it may cause irritation. Lesions that do
not improve or that worsen on therapy should be evaluated for secondary
bacterial infection. The effect of DENAVIR has not been established in
immunocompromised patients.
Nonclinical Toxicology
Carcinogenesis, Mutagenesis,
Impairment of Fertility
In clinical trials, systemic
drug exposure following topical administration of penciclovir cream was
negligible, as the penciclovir content of all plasma and urine samples was
below the limit of assay detection (0.1 mcg/mL and 10 mcg/mL, respectively). However,
for the purpose of inter-species dose comparisons presented in the following
sections, an assumption of 100% absorption of penciclovir from the topically
applied product has been used. Based on the use of the maximal recommended
topical dose of penciclovir of 0.05 mg/kg/day and an assumption of 100%
absorption, the maximum theoretical plasma AUC0-24 hrs for penciclovir is
approximately 0.129 mcg.hr/mL.
Carcinogenesis
Two-year carcinogenicity
studies were conducted with famciclovir (the oral prodrug of penciclovir) in
rats and mice. An increase in the incidence of mammary adenocarcinoma (a common
tumor in female rats of the strain used) was seen in female rats receiving 600
mg/kg/day (approximately 395x the maximum theoretical human exposure to penciclovir
following application of the topical product, based on area under the plasma
concentration curve comparisons [24 hr. AUC]). No increases in tumor incidence
were seen among male rats treated at doses up to 240 mg/kg/day (approximately
190x the maximum theoretical human AUC for penciclovir), or in male and female
mice at doses up to 600 mg/kg/day (approximately 100x the maximum theoretical
human AUC for penciclovir).
Mutagenesis
When tested in vitro,
penciclovir did not cause an increase in gene mutation in the Ames assay using
multiple strains of S. typhimurium or E. coli(at up to 20,000 mcg/plate), nor
did it cause an increase in unscheduled DNA repair in mammalian HeLa S3 cells
(at up to 5,000 mcg/mL). However, an increase in clastogenic responses was seen
with penciclovir in the L5178Y mouse lymphoma cell assay (at doses ≥ 1000
mcg/mL) and, in human lymphocytes incubated in vitro at doses ≥ 250
mcg/mL. When tested in vivo, penciclovir caused an increase in micronuclei in
mouse bone marrow following the intravenous administration of doses ≥ 500
mg/kg ( ≥ 810x the maximum human dose, based on body surface area
conversion).
Impairment of Fertility
Testicular toxicity was
observed in multiple animal species (rats and dogs) following repeated
intravenous administration of penciclovir (160 mg/kg/day and 100 mg/kg/day,
respectively, approximately 1155 and 3255x the maximum theoretical human AUC).
Testicular changes seen in both species included atrophy of the seminiferous
tubules and reductions in epididymal sperm counts and/or an increased incidence
of sperm with abnormal morphology or reduced motility. Adverse testicular
effects were related to an increasing dose or duration of exposure to
penciclovir. No adverse testicular or reproductive effects (fertility and
reproductive function) were observed in rats after 10 to 13 weeks dosing at 80
mg/kg/day, or testicular effects in dogs after 13 weeks dosing at 30 mg/kg/day
(575 and 845x the maximum theoretical human AUC, respectively). Intravenously
administered penciclovir had no effect on fertility or reproductive performance
in female rats at doses of up to 80 mg/kg/day (260x the maximum human dose
[BSA]). There was no evidence of any clinically significant effects on sperm
count, motility or morphology in 2 placebo-controlled clinical trials of Famvir® (famciclovir [the oral prodrug of penciclovir], 250 mg b.i.d.; n=66) in
immunocompetent men with recurrent genital herpes, when dosing and follow-up
were maintained for 18 and 8 weeks, respectively (approximately 2 and 1
spermatogenic cycles in the human).
Use In Specific Populations
Pregnancy
Category B
There are no adequate and well-controlled studies in
pregnant women.
Animal Data
No adverse effects on the course and outcome of pregnancy
or on fetal development were noted in rats and rabbits following the
intravenous administration of penciclovir at doses of 80 and 60 mg/kg/day,
respectively (estimated human equivalent doses of 13 and 18 mg/kg/day for the
rat and rabbit, respectively, based on body surface area conversion; the body
surface area doses being 260 and 355x the maximum recommended dose following
topical application of the penciclovir cream). Because animal reproduction
studies are not always predictive of human response, penciclovir should be used
during pregnancy only if clearly needed.
Nursing Mothers
There is no information on whether penciclovir is
excreted in human milk after topical administration. However, following oral
administration of famciclovir (the oral prodrug of penciclovir) to lactating
rats, penciclovir was excreted in breast milk at concentrations higher than
those seen in the plasma. Therefore, a decision should be made whether to
discontinue the drug, taking into account the importance of the drug to the
mother. There are no data on the safety of penciclovir in newborns.
Pediatric Use
An open-label, uncontrolled trial with penciclovir cream
1% was conducted in 102 patients, ages 1217 years, with recurrent herpes
labialis. The frequency of adverse events was generally similar to the
frequency previously reported for adult patients. Safety and effectiveness in
pediatric patients less than 12 years of age have not been established.
Geriatric Use
In 74 patients ≥ 65 years of age, the adverse
events profile was comparable to that observed in younger patients.