Xin Xin

Xin Xin Cream is indicated for the treatment of interdigital tinea pedis, tinea cruris, and tinea corporis caused by the organism Trichophyton rubrum.

NAFTIN Cream is indicated for the treatment of interdigital tinea pedis, tinea cruris, and tinea corporis caused by the organism Trichophyton rubrum.

For topical use only. Xin Xin Cream is not for ophthalmic, oral, or intravaginal use. Apply a thin layer of Xin Xin Cream once-daily to the affected areas plus a ½ inch margin of healthy surrounding skin for 2 weeks.

For topical use only. NAFTIN Cream is not for ophthalmic, oral, or intravaginal use. Apply a thin layer of NAFTIN Cream once-daily to the affected areas plus a ½ inch margin of healthy surrounding skin for 2 weeks.

WARNINGS

Included as part of the "PRECAUTIONS" Section

PRECAUTIONS

Local Adverse Reactions

Discontinue treatment if irritation or sensitivity develops with the use of Xin Xin Cream. Direct patients to contact their physician if these conditions develop following use of Xin Xin Cream.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Long-term studies to evaluate the carcinogenic potential of Xin Xin Cream have not been performed.

Naftifine hydrochloride revealed no evidence of mutagenic or clastogenic potential based on the results of two in vitro genotoxicity tests (Ames assay and Chinese hamster ovary cell chromosome aberration assay) and one in vivo genotoxicity test (mouse bone marrow micronucleus assay).

Oral administration of naftifine hydrochloride to rats, throughout mating, gestation, parturition and lactation, demonstrated no effects on growth, fertility or reproduction, at doses up to 100 mg/kg/day ( 6 times MRHD).

Use In Specific Populations

Pregnancy

Risk Summary

There are no available data with Xin Xin Cream in pregnant women to inform the drug-associated risk for major birth defects and miscarriage. In animal reproduction studies, no adverse effects on embryofetal development were seen at oral doses administered during the period of organogenesis up to 18 times the maximum recommended human dose (MRHD) in pregnant rats or subcutaneous doses administered during the period of organogenesis up to 2 times the MRHD in pregnant rats or 4 times the MRHD in pregnant rabbits.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Data

Animal Data

Systemic embryofetal development studies were conducted in rats and rabbits. For the comparison of animal to human doses based on body surface area comparison (mg/m²), the MRHD is set at 8 g 2% cream per day (2.67 mg/kg/day for a 60 kg individual).

Oral doses of 30, 100 and 300 mg/kg/day naftifine hydrochloride were administered during the period of organogenesis to pregnant female rats. No treatment-related effects on embryofetal development were noted at doses up to 300 mg/kg/day ( 18 times MRHD). Subcutaneous doses of 10 and 30 mg/kg/day naftifine hydrochloride were administered during the period of organogenesis to pregnant female rats. No treatment-related effects on embryofetal development were noted at 30 mg/kg/day (2 times MRHD). Subcutaneous doses of 3, 10 and 30 mg/kg/day naftifine hydrochloride were administered during the period of organogenesis to pregnant female rabbits. No treatment related effects on embryofetal development were noted at 30 mg/kg/day ( 4 times MRHD).

A peri-and post-natal development study was conducted in rats. Oral doses of 30, 100 and 300 mg/kg/day naftifine hydrochloride were administered to female rats from gestational day 14 to lactation day 21. Reduced body weight gain of females during gestation and of the offspring during lactation was noted at 300 mg/kg/day (18 times MRHD). No developmental toxicity was noted at 100 mg/kg/day ( 6 times MRHD).

Lactation

Risk Summary

There is no information available on the presence of Xin Xin Cream in human milk, the effects of the drug on the breastfed infant, or the effects of the drug on milk production. The lack of clinical data during lactation precludes a clear determination of the risk of Xin Xin Cream to an infant during lactation; therefore, the development and health benefits of breastfeeding should be considered along with the mother’s clinical need for Xin Xin cream and any potential adverse effects on the breastfed infant from Xin Xin cream or from the underlying maternal condition.

Pediatric Use

The safety and effectiveness of Xin Xin Cream have been established in pediatric patients age 12 and above with interdigital tinea pedis and tinea cruris and age 2 and above with tinea corporis.

Use of Xin Xin Cream in these age groups is supported by evidence from adequate and well controlled studies in adults and children, with additional safety and PK data from two open label trials conducted in 49 pediatric subjects exposed to Xin Xin Cream.

Safety and effectiveness of Xin Xin Cream in the treatment of tinea cruris and interdigital tinea pedis in pediatric patients less than 12 years of age have not been established. Safety and effectiveness of Xin Xin Cream in the treatment of tinea corporis in pediatric patients less than 2 years of age have not been established.

Geriatric Use

Clinical studies of Xin Xin Cream did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects.

WARNINGS

Included as part of the "PRECAUTIONS" Section

PRECAUTIONS

Local Adverse Reactions

Discontinue treatment if irritation or sensitivity develops with the use of NAFTIN Cream. Direct patients to contact their physician if these conditions develop following use of NAFTIN Cream.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment Of Fertility

Long-term studies to evaluate the carcinogenic potential of NAFTIN Cream have not been performed.

Naftifine hydrochloride revealed no evidence of mutagenic or clastogenic potential based on the results of two in vitro genotoxicity tests (Ames assay and Chinese hamster ovary cell chromosome aberration assay) and one in vivo genotoxicity test (mouse bone marrow micronucleus assay).

Oral administration of naftifine hydrochloride to rats, throughout mating, gestation, parturition and lactation, demonstrated no effects on growth, fertility or reproduction, at doses up to 100 mg/kg/day ( 6 times MRHD).

Use In Specific Populations

Pregnancy

Risk Summary

There are no available data with NAFTIN Cream in pregnant women to inform the drug-associated risk for major birth defects and miscarriage. In animal reproduction studies, no adverse effects on embryofetal development were seen at oral doses administered during the period of organogenesis up to 18 times the maximum recommended human dose (MRHD) in pregnant rats or subcutaneous doses administered during the period of organogenesis up to 2 times the MRHD in pregnant rats or 4 times the MRHD in pregnant rabbits.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Data

Animal Data

Systemic embryofetal development studies were conducted in rats and rabbits. For the comparison of animal to human doses based on body surface area comparison (mg/m²), the MRHD is set at 8 g 2% cream per day (2.67 mg/kg/day for a 60 kg individual).

Oral doses of 30, 100 and 300 mg/kg/day naftifine hydrochloride were administered during the period of organogenesis to pregnant female rats. No treatment-related effects on embryofetal development were noted at doses up to 300 mg/kg/day ( 18 times MRHD). Subcutaneous doses of 10 and 30 mg/kg/day naftifine hydrochloride were administered during the period of organogenesis to pregnant female rats. No treatment-related effects on embryofetal development were noted at 30 mg/kg/day (2 times MRHD). Subcutaneous doses of 3, 10 and 30 mg/kg/day naftifine hydrochloride were administered during the period of organogenesis to pregnant female rabbits. No treatment related effects on embryofetal development were noted at 30 mg/kg/day ( 4 times MRHD).

A peri-and post-natal development study was conducted in rats. Oral doses of 30, 100 and 300 mg/kg/day naftifine hydrochloride were administered to female rats from gestational day 14 to lactation day 21. Reduced body weight gain of females during gestation and of the offspring during lactation was noted at 300 mg/kg/day (18 times MRHD). No developmental toxicity was noted at 100 mg/kg/day ( 6 times MRHD).

Lactation

Risk Summary

There is no information available on the presence of NAFTIN Cream in human milk, the effects of the drug on the breastfed infant, or the effects of the drug on milk production. The lack of clinical data during lactation precludes a clear determination of the risk of NAFTIN Cream to an infant during lactation; therefore, the development and health benefits of breastfeeding should be considered along with the mother’s clinical need for NAFTIN cream and any potential adverse effects on the breastfed infant from NAFTIN cream or from the underlying maternal condition.

Pediatric Use

The safety and effectiveness of NAFTIN Cream have been established in pediatric patients age 12 and above with interdigital tinea pedis and tinea cruris and age 2 and above with tinea corporis.

Use of NAFTIN Cream in these age groups is supported by evidence from adequate and well controlled studies in adults and children, with additional safety and PK data from two open label trials conducted in 49 pediatric subjects exposed to NAFTIN Cream.

Safety and effectiveness of Naftin Cream in the treatment of tinea cruris and interdigital tinea pedis in pediatric patients less than 12 years of age have not been established. Safety and effectiveness of Naftin Cream in the treatment of tinea corporis in pediatric patients less than 2 years of age have not been established.

Geriatric Use

Clinical studies of NAFTIN Cream did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

During clinical trials, 903 subjects were exposed to naftifine 1% and 2% cream formulations. A total of 564 subjects with interdigital tinea pedis, tinea cruris, or tinea corporis were treated with Xin Xin Cream.

In two randomized, vehicle-controlled trials (400 patients were treated with Xin Xin Cream). The population was 12 to 88 years old, primarily male (79%), 48% Caucasian, 36% Black or African American, 40% Hispanic or Latino and had either predominantly interdigital tinea pedis or tinea cruris. Most subjects received doses once-daily, topically, for 2 weeks to cover the affected skin areas plus a ½ inch margin of surrounding healthy skin. In the two vehicle-controlled trials, 17.5% of Xin Xin Cream treated subjects experienced an adverse reaction compared with 19.3% of vehicle subjects. The most common adverse reaction (≥1%) is pruritus. Most adverse reactions were mild in severity. The incidence of adverse reactions in the Xin Xin Cream treated population was not significantly different than in the vehicle treated population.

In a third randomized, vehicle-controlled trial, 116 pediatric subjects with tinea corporis were treated with Xin Xin Cream. The population was aged ≥2 to <18 years (mean age of 9 years), predominantly male (61%), 47% White, 51% Black or African American, 92% Hispanic or Latino, and infected with tinea corporis. Xin Xin Cream was topically applied once daily for 2 weeks to all affected body surface areas with tinea corporis plus a ½ inch margin of healthy skin surrounding the affected lesions. The incidence of adverse reactions in the Xin Xin Cream treated population was not significantly different than in the vehicle treated population.

In two open-label pediatric pharmacokinetics and safety trials, 49 pediatric subjects 2 to <18 years of age with interdigital tinea pedis, tinea cruris, and tinea corporis received Xin Xin Cream. The incidence of adverse reactions in the pediatric population was similar to that observed in the adult population.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of naftifine hydrochloride: redness/irritation, inflammation, maceration, swelling, burning, blisters, serous drainage, crusting, headache, dizziness, leukopenia, agranulocytosis.

Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

During clinical trials, 903 subjects were exposed to naftifine 1% and 2% cream formulations. A total of 564 subjects with interdigital tinea pedis, tinea cruris, or tinea corporis were treated with NAFTIN Cream.

In two randomized, vehicle-controlled trials (400 patients were treated with NAFTIN Cream). The population was 12 to 88 years old, primarily male (79%), 48% Caucasian, 36% Black or African American, 40% Hispanic or Latino and had either predominantly interdigital tinea pedis or tinea cruris. Most subjects received doses once-daily, topically, for 2 weeks to cover the affected skin areas plus a ½ inch margin of surrounding healthy skin. In the two vehicle-controlled trials, 17.5% of NAFTIN Cream treated subjects experienced an adverse reaction compared with 19.3% of vehicle subjects. The most common adverse reaction (≥1%) is pruritus. Most adverse reactions were mild in severity. The incidence of adverse reactions in the NAFTIN Cream treated population was not significantly different than in the vehicle treated population.

In a third randomized, vehicle-controlled trial, 116 pediatric subjects with tinea corporis were treated with NAFTIN Cream. The population was aged ≥2 to <18 years (mean age of 9 years), predominantly male (61%), 47% White, 51% Black or African American, 92% Hispanic or Latino, and infected with tinea corporis. NAFTIN Cream was topically applied once daily for 2 weeks to all affected body surface areas with tinea corporis plus a ½ inch margin of healthy skin surrounding the affected lesions. The incidence of adverse reactions in the NAFTIN Cream treated population was not significantly different than in the vehicle treated population.

In two open-label pediatric pharmacokinetics and safety trials, 49 pediatric subjects 2 to <18 years of age with interdigital tinea pedis, tinea cruris, and tinea corporis received NAFTIN Cream. The incidence of adverse reactions in the pediatric population was similar to that observed in the adult population.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of naftifine hydrochloride: redness/irritation, inflammation, maceration, swelling, burning, blisters, serous drainage, crusting, headache, dizziness, leukopenia, agranulocytosis.

Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

The pharmacodynamics of Xin Xin Cream have not been established.

The pharmacodynamics of NAFTIN Cream have not been established.

In vitro and in vivo bioavailability studies have demonstrated that naftifine penetrates the stratum corneum in sufficient concentration to inhibit the growth of dermatophytes.

The pharmacokinetics of Xin Xin Cream was evaluated following once-daily topical application for 2 weeks to 21 adult subjects, both males and females, with both tinea pedis and tinea cruris. The median total amount of cream applied was 6.4 g (range 5.3-7.5 g) per day. The results showed that the systemic exposure (i.e., maximum concentration (Cmax) and area under the curve from time 0 to 24 hours (AUC0-24)) to naftifine increased over the 2 week treatment period in all the 21 subjects. Geometric mean (coefficient of variation or CV%) AUC0-24 was 117 (41.2) ng*hr/mL on Day 1, and 204 (28.5) ng*hr/mL on Day 14. Geometric mean (CV %) Cmax was 7 ng/mL (55.6) on Day 1 and 11 ng/mL (29.3) on day 14. Median time to Cmax (Tmax) was 8.0 hours (range 4-24 hours) on Day 1 and 6.0 hours (range 0-16 hours) on Day 14. Accumulation after 14 days of topical application was less than two fold. Trough concentrations generally increased throughout the 14 day study period. Naftifine continued to be detected in plasma in 13/21 (62%) subjects on day 28, the mean (standard deviation or SD) plasma concentrations were 1.6 ± 0.5 ng/mL (range below limit of quantitation (BLQ) to 3 ng/mL). In the same pharmacokinetic trial conducted in patients with tinea pedis and tinea cruris, median fraction of the dose excreted in urine during the treatment period was 0.0016% on Day 1 versus 0.0020% on Day 14.

In a second trial that enrolled 22 subjects, the pharmacokinetics of Xin Xin Cream was evaluated in 20 pediatric subjects 13 to <18 years of age with both tinea pedis and tinea cruris. Subjects were treated with a median dose of 8.1 g (range 6.6-10.1 g) applied to the affected areas once daily for 2 weeks. The results showed that the systemic exposure increased over the treatment period. Geometric mean (CV%) AUC0-24 was 138 (50.2) ng*hr/mL on Day 1, and 192 (74.9) ng*hr/mL on Day 14. Geometric mean (CV %) Cmax was 9.21 ng/mL (48.4) on Day 1 and 12.7 ng/mL (67.2) on day 14. Median fraction of the dose excreted in urine during the treatment period was 0.0030% on Day 1 and 0.0033% on Day 14.

A third trial evaluated the pharmacokinetics of Xin Xin Cream in 27 pediatric subjects 2 to < 12 years of age with at least moderate tinea corporis. Subjects were divided into younger (ages 2 to < 6 years, 17 subjects) and older (6 to <12 years, 10 subjects) groups. Median doses of 1.3 g (range 1.0-3.1 g) and 2.3 g (range 2.24.2 g) were applied once-daily for 2 weeks in the younger and older groups, respectively, to the affected area plus a ½ inch margin. Plasma and urine pharmacokinetic assessments were conducted on Day 1 in the older group only and on Day 14 in both groups. All subjects showed measurable levels of naftifine in plasma after topical application of Xin Xin Cream. Following a single dose on Day 1 in subjects 6 to < 12 years of age, the geometric mean (CV%) values of Cmax and AUC0-24 were 3.60 (76.6) ng/mL and 49.8 (64.4) ng*h/mL, respectively. On Day 14 in this group, the Cmax and AUC0-24 were 3.31 (51.2) ng/mL and 52.4 (49.2) ng*h/mL, respectively. In subjects 2 to < 6 years of age on Day 14, the Cmax and AUC0-24 were 3.98 (186) ng/mL and 54.8 (150) ng*h/mL, respectively. In the older group of subjects 6 to 12 years of age, the systemic exposures (both Cmax and AUC0-24) on Days 1 and 14 were comparable. The median fraction of the dose excreted into urine over 24 hours following drug applications on Day 1 and Day 14 was 0.0029% and 0.0014%, respectively.

In vitro and in vivo bioavailability studies have demonstrated that naftifine penetrates the stratum corneum in sufficient concentration to inhibit the growth of dermatophytes.

The pharmacokinetics of NAFTIN Cream was evaluated following once-daily topical application for 2 weeks to 21 adult subjects, both males and females, with both tinea pedis and tinea cruris. The median total amount of cream applied was 6.4 g (range 5.3-7.5 g) per day. The results showed that the systemic exposure (i.e., maximum concentration (Cmax) and area under the curve from time 0 to 24 hours (AUC0-24)) to naftifine increased over the 2 week treatment period in all the 21 subjects. Geometric mean (coefficient of variation or CV%) AUC0-24 was 117 (41.2) ng*hr/mL on Day 1, and 204 (28.5) ng*hr/mL on Day 14. Geometric mean (CV %) Cmax was 7 ng/mL (55.6) on Day 1 and 11 ng/mL (29.3) on day 14. Median time to Cmax (Tmax) was 8.0 hours (range 4-24 hours) on Day 1 and 6.0 hours (range 0-16 hours) on Day 14. Accumulation after 14 days of topical application was less than two fold. Trough concentrations generally increased throughout the 14 day study period. Naftifine continued to be detected in plasma in 13/21 (62%) subjects on day 28, the mean (standard deviation or SD) plasma concentrations were 1.6 ± 0.5 ng/mL (range below limit of quantitation (BLQ) to 3 ng/mL). In the same pharmacokinetic trial conducted in patients with tinea pedis and tinea cruris, median fraction of the dose excreted in urine during the treatment period was 0.0016% on Day 1 versus 0.0020% on Day 14.

In a second trial that enrolled 22 subjects, the pharmacokinetics of NAFTIN Cream was evaluated in 20 pediatric subjects 13 to <18 years of age with both tinea pedis and tinea cruris. Subjects were treated with a median dose of 8.1 g (range 6.6-10.1 g) applied to the affected areas once daily for 2 weeks. The results showed that the systemic exposure increased over the treatment period. Geometric mean (CV%) AUC0-24 was 138 (50.2) ng*hr/mL on Day 1, and 192 (74.9) ng*hr/mL on Day 14. Geometric mean (CV %) Cmax was 9.21 ng/mL (48.4) on Day 1 and 12.7 ng/mL (67.2) on day 14. Median fraction of the dose excreted in urine during the treatment period was 0.0030% on Day 1 and 0.0033% on Day 14.

A third trial evaluated the pharmacokinetics of NAFTIN Cream in 27 pediatric subjects 2 to < 12 years of age with at least moderate tinea corporis. Subjects were divided into younger (ages 2 to < 6 years, 17 subjects) and older (6 to <12 years, 10 subjects) groups. Median doses of 1.3 g (range 1.0-3.1 g) and 2.3 g (range 2.24.2 g) were applied once-daily for 2 weeks in the younger and older groups, respectively, to the affected area plus a ½ inch margin. Plasma and urine pharmacokinetic assessments were conducted on Day 1 in the older group only and on Day 14 in both groups. All subjects showed measurable levels of naftifine in plasma after topical application of NAFTIN Cream. Following a single dose on Day 1 in subjects 6 to < 12 years of age, the geometric mean (CV%) values of Cmax and AUC0-24 were 3.60 (76.6) ng/mL and 49.8 (64.4) ng*h/mL, respectively. On Day 14 in this group, the Cmax and AUC0-24 were 3.31 (51.2) ng/mL and 52.4 (49.2) ng*h/mL, respectively. In subjects 2 to < 6 years of age on Day 14, the Cmax and AUC0-24 were 3.98 (186) ng/mL and 54.8 (150) ng*h/mL, respectively. In the older group of subjects 6 to 12 years of age, the systemic exposures (both Cmax and AUC0-24) on Days 1 and 14 were comparable. The median fraction of the dose excreted into urine over 24 hours following drug applications on Day 1 and Day 14 was 0.0029% and 0.0014%, respectively.