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—KERYDIN 5%外用溶液获FDA批准，用于局部治疗甲真菌感染新药
7 DRUG INTERACTIONS In vitro studies have shown that tavaborole, at therapeutic concentrations, neither inhibits nor induces cytochrome P450 (CYP450) enzymes. 8 USE IN SPECIFIC POPULATIONS 8.1 Pregnancy Pregnancy Category C There are no adequate and well-controlled studies with KERYDIN in pregnant women. KERYDIN should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Systemic embryofetal development studies were conducted in rats and rabbits and a dermal embryofetal development study was conducted in rabbits. Oral administration: In an oral embryofetal development study in rats, oral doses of 30, 100, and 300 mg/kg/day tavaborole were administered during the period of organogenesis (gestational days 6-19) to pregnant female rats. In the presence of maternal toxicity, embryofetal toxicity (increased embryofetal resorption and/or deaths) and drug-related skeletal malformations and variations suggestive of delayed development (i.e., a delay in ossification) were noted in fetuses at 300 mg/kg/day tavaborole [570 times the Maximum Recommended Human Dose (MRHD) based on Area Under the Curve (AUC) comparisons]. No developmental toxicity was noted in rats at 100 mg/kg/day tavaborole (26 times the MRHD based on AUC comparisons). In an oral embryofetal development study in rabbits, oral doses of 15, 50, and 150 mg/kg/day tavaborole were administered during the period of organogenesis (gestational days 7-19) to pregnant female rabbits. In the presence of maternal toxicity, excessive embryofetal mortality due to post-implantation loss was noted at 150 mg/kg/day tavaborole. No drug related malformations were noted in rabbits at 150 mg/kg/day tavaborole (155 times the MRHD based on AUC comparisons). No embryofetal mortality was noted in rabbits at 50 mg/kg/day tavaborole (16 times the MRHD based on AUC comparisons). Topical administration: In a dermal embryofetal development study in rabbits, topical doses of 1%, 5%, and 10% tavaborole solution were administered during the period of organogenesis (gestational days 6-28) to pregnant female rabbits. A dose dependent increase in dermal irritation at the treatment site was noted at 5% and 10% tavaborole solution. A decrease in fetal bodyweight was noted at 10% tavaborole solution. No drug related malformations were noted in rabbits at 10% tavaborole solution (36 times the MRHD based on AUC comparisons). No embryofetal toxicity was noted in rabbits at 5% tavaborole solution (26 times the MRHD based on AUC comparisons). Nonteratogenic effects: In an oral pre- and post-natal development study in rats, oral doses of 15, 60, and 100 mg/kg/day tavaborole were administered from the beginning of organogenesis (gestation day 6) through the end of lactation (lactation day 20). In the presence of minimal maternal toxicity, no embryofetal toxicity or effects on postnatal development were noted at 100 mg/kg/day (29 times the MRHD based on AUC comparisons). 8.3 Nursing Mothers It is not known whether tavaborole is excreted in human milk following topical application of KERYDIN. Because many drugs are excreted in human milk, caution should be exercised when KERYDIN is administered to a nursing woman. 8.4 Pediatric Use Safety and effectiveness in pediatric patients have not been established. 8.5 Geriatric Use In clinical trials of 791 subjects who were exposed to KERYDIN, 19% were 65 years of age and over, while 4% were 75 years of age and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, but greater sensitivity of some older individuals cannot be ruled out. 11 DESCRIPTION KERYDIN (tavaborole) topical solution, 5% contains tavaborole, 5% (w/w) in a clear, colorless alcohol-based solution for topical use. The active ingredient, tavaborole, is an oxaborole antifungal with the chemical name of 5-fluoro-1,3-dihydro-1-hydroxy-2,1-benzoxaborole. The chemical formula is C7H6BFO2, the molecular weight is 151.93 and the structural formula is: Tavaborole is a white to off-white powder. It is slightly soluble in water and freely soluble in ethanol and propylene glycol. Each mL of KERYDIN contains 43.5 mg of tavaborole. Inactive ingredients include alcohol, edetate calcium disodium, and propylene glycol. 12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action KERYDIN is an oxaborole antifungal [see Clinical Pharmacology (12.4)]. 12.2 Pharmacodynamics At therapeutic doses, KERYDIN is not expected to prolong QTc to any clinically relevant extent. 12.3 Pharmacokinetics Tavaborole undergoes extensive metabolism. Renal excretion is the major route of elimination. In a clinical pharmacology trial of six healthy adult male volunteers who received a single topical application of 5% 14C-tavaborole solution, tavaborole conjugates and metabolites were shown to be excreted primarily in the urine. The pharmacokinetics of tavaborole was investigated in 24 subjects with distal subungual onychomycosis involving at least 4 toenails (including at least 1 great toenail) following a single dose and a 2-week daily topical application of 200 μL of a 5% solution of tavaborole to all ten toenails and 2 mm of skin surrounding each toenail. Steady state was achieved after 14 days of dosing. After a single dose, the mean (± standard deviation) peak concentration (Cmax) of tavaborole was 3.54 ± 2.26 ng/mL (n=21 with measurable concentrations, range 0.618-10.2 ng/mL, LLOQ=0.5 ng/mL), and the mean AUClast was 44.4 ± 25.5 ng*hr/mL (n=21). After 2 weeks of daily dosing, the mean Cmax was 5.17 ± 3.47 ng/mL (n=24, range 1.51-12.8 ng/mL), and the mean AUCτ was 75.8 ± 44.5 ng*hr/mL. 12.4 Microbiology Mechanism of Action The mechanism of action of tavaborole is inhibition of fungal protein synthesis. Tavaborole inhibits protein synthesis by inhibition of an aminoacyl-transfer ribonucleic acid (tRNA) synthetase (AARS). Activity in vitro and in clinical infections Tavaborole has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections [see Indications and Usage (1)]: Trichophyton rubrum Trichophyton mentagrophytes Mechanism of Resistance Trichophyton mentagrophytes and Trichophyton rubrum strains from isolates collected in the clinical trials have not demonstrated resistance following repeated exposure to tavaborole. 13 NONCLINICAL TOXICOLOGY 13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility In an oral carcinogenicity study in Sprague-Dawley rats, oral doses of 12.5, 25, and 50 mg/kg/day tavaborole were administered to rats once daily for 104 weeks. No drug related neoplastic findings were noted at oral doses up to 50 mg/kg/day tavaborole (14 times the MRHD based on AUC comparisons). In a dermal carcinogenicity study in CD-1 mice, topical doses of 5%, 10%, and 15% tavaborole solution were administered to mice once daily for 104 weeks. No drug related neoplastic findings were noted at topical doses up to 15% tavaborole solution (89 times the MRHD based on AUC comparisons). Tavaborole revealed no evidence of mutagenic or clastogenic potential based on the results of two in vitro genotoxicity tests (Ames assay and Human lymphocyte chromosomal aberration assay) and one in vivo genotoxicity test (rat micronucleus assay). No effects on fertility were observed in male and female rats that were administered oral doses up to 300 mg/kg/day tavaborole (107 times the MRHD based on AUC comparisons) prior to and during early pregnancy. 14 CLINICAL STUDIES The efficacy and safety of KERYDIN was evaluated in two multicenter, double-blind, randomized, vehicle-controlled trials. KERYDIN or vehicle was applied once daily for 48 weeks in subjects with 20% to 60% clinical involvement of the target toenail, without dermatophytomas or lunula (matrix) involvement. A total of 1194 subjects (795 KERYDIN, 399 Vehicle) 18 to 88 years of age, 82% male, 84% white, participated in these two trials. Efficacy assessments were made at 52 weeks following a 48-week treatment period. The Complete Cure efficacy endpoint included negative mycology (negative KOH wet mount and negative fungal culture) and Completely Clear Nail (no clinical evidence of onychomycosis as evidenced by a normal toenail plate, no onycholysis, and no subungual hyperkeratosis). Efficacy results from the two trials are summarized in Table 2. Table 2: Efficacy Outcomes
a. Complete cure defined as 0% clinical involvement of the target toenail plus negative KOH and negative culture. | |||||||||||||||||||||||||||||||||||||||
