Adapalene and Benzoyl Peroxide (Page 2 of 4)

6.2 Postmarketing Experience

The following adverse reactions have been identified during postapproval use of adapalene and benzoyl peroxide topical gel. 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.

Skin and subcutaneous tissue disorders: sunburn, blister (including vesicles and bullae), pruritus, hyperpigmentation and hypopigmentation.

8 USE IN SPECIFIC POPULATIONS

8.1 Pregnancy

Risk Summary

Available pharmacovigilance data with adapalene and benzoyl peroxide topical gel use in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes. Animal reproduction studies have not been conducted with the combination gel.

Adapalene gel, 0.3%

Available data from clinical trials with adapalene gel 0.3% use in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage or other adverse maternal or fetal outcomes. In animal reproduction studies, oral administration of adapalene to pregnant rats and rabbits during organogenesis at dose exposures 41 and 81 times, respectively, the human exposure at the maximum recommended human dose (MRHD) of 2 g resulted in fetal skeletal and visceral malformations (see Data).

Benzoyl peroxide gel, 2.5%

The systemic exposure of benzoyl peroxide is unknown. Based on published literature, benzoyl peroxide is rapidly metabolized to benzoic acid (an endogenous substance), which is eliminated in the urine. Hence, maternal use is not expected to result in fetal exposure of the drug.

The 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 risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Data

Animal Data

No malformations were observed in rats treated with oral adapalene doses of 0.15 to 5.0 mg/kg/day, up to 8 times the MRHD of 2 grams of adapalene and benzoyl peroxide topical gel based on a mg/m² comparison. However, malformations were observed in rats and rabbits when treated with oral doses of ≥25 mg/kg/day adapalene (41 and 81 times the MRHD, respectively, based on a mg/m² comparison). Findings included cleft palate, microphthalmia, encephalocele, and skeletal abnormalities in rats and umbilical hernia, exophthalmos, and kidney and skeletal abnormalities in rabbits.

Dermal adapalene embryofetal development studies in rats and rabbits at doses up to 6.0 mg/kg/day (9.7 and 19.5 times the MRHD, respectively, based on a mg/m² comparison) exhibited no fetotoxicity and only minimal increases in skeletal variations (supernumerary ribs in both species and delayed ossification in rabbits).

8.2 Lactation

Risk Summary

Adapalene gel, 0.3%

There are no data on the presence of adapalene topical gel or its metabolite in human milk, the effects on the breastfed infant, or the effects on milk production. In animal studies, adapalene is present in rat milk with oral administration of the drug. When a drug is present in animal milk, it is likely that the drug will be present in human milk. It is possible that topical administration of large amounts of adapalene could result in sufficient systemic absorption to produce detectable quantities in human milk (see Clinical Considerations).

Benzoyl peroxide gel, 2.5%

The systemic exposure of benzoyl peroxide is unknown. Based on the published literature, benzoyl peroxide is rapidly metabolized to benzoic acid (an endogenous substance), which is eliminated in the urine. Any amount of benzoyl peroxide excreted into human milk by a nursing mother would be expected to be rapidly metabolized by tissue and stomach esterases. There are no data on the presence of benzoyl peroxide in human milk, its effects on the breastfed infant or its effects on milk production.

The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for adapalene and benzoyl peroxide topical gel and any potential adverse effects on the breastfed child from adapalene and benzoyl peroxide topical gel or from the underlying maternal condition.

Clinical Considerations

To minimize potential exposure to the breastfed infant via breastmilk, use adapalene and benzoyl peroxide topical gel on the smallest area of skin and for the shortest duration possible while breastfeeding. Advise breastfeeding women not to apply adapalene and benzoyl peroxide topical gel directly to the nipple and areola to avoid direct infant exposure.

8.4 Pediatric Use

Safety and effectiveness of adapalene and benzoyl peroxide topical gel in pediatric patients under the age of 12 have not been established.

8.5 Geriatric Use

Clinical studies of adapalene and benzoyl peroxide topical gel did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from younger subjects.

11 DESCRIPTION

Adapalene and benzoyl peroxide topical gel, 0.3%/2.5% is a white to very pale yellow, opaque gel for topical use containing adapalene USP, 0.3% and benzoyl peroxide USP, 2.5%.

Adapalene USP, a synthetic retinoid, is a naphthoic acid derivative with retinoid-like properties. The chemical name for adapalene, USP is (6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid). It has the following structural formula:

Adapalene, USP:

Molecular formula: C₂₈ H₂₈ O₃ Molecular weight: 412.5

Benzoyl peroxide, USP is a highly lipophilic oxidizing agent that localizes in both bacterial and keratinocyte cell membranes. The chemical name for benzoyl peroxide, USP is dibenzoyl peroxide. It has the following structural formula:

Benzoyl Peroxide, USP:

Molecular formula: C₁₄ H₁₀ O₄ Molecular weight: 242.23

Adapalene and benzoyl peroxide topical gel 0.3%/2.5% contains the following inactive ingredients: carbomer 980, docusate sodium, edetate disodium, glycerin, poloxamer 124, propylene glycol, purified water, sodium hydroxide, and sorbitan monooleate.

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Adapalene

Adapalene binds to specific retinoic acid nuclear receptors but does not bind to cytosolic receptor protein. Biochemical and pharmacological profile studies have demonstrated that adapalene is a modulator of cellular differentiation, keratinization and inflammatory processes. However, the significance of these findings with regard to the mechanism of action of adapalene for the treatment of acne is unknown.

Benzoyl peroxide

Benzoyl peroxide is an oxidizing agent with bactericidal and keratolytic effects.

12.2 Pharmacodynamics

Pharmacodynamics of adapalene and benzoyl peroxide topical gel is unknown.

12.3 Pharmacokinetics

A pharmacokinetic trial was conducted in 26 adult and adolescent subjects (12 to 33 years of age) with severe acne vulgaris who were treated with once-daily applications during a 4-week period with, on average, 2.3 grams/day (range 1.6 to 3.1 grams/day) of adapalene and benzoyl peroxide topical gel applied as a thin layer to the face, shoulders, upper chest and upper back. After a 4-week treatment, 16 subjects (62%) had quantifiable adapalene plasma concentrations above the limit of quantification of 0.1 ng/mL, with a mean C_max of 0.16 ± 0.08 ng/mL and a mean AUC_0-24hr of 2.49 ± 1.21 ng.h/mL. The most exposed subject had adapalene C_max and AUC_0-24hr of 0.35 ng/mL and 6.41 ng.h/mL, respectively. Excretion of adapalene appears to be primarily by the biliary route. Benzoyl peroxide is absorbed by the skin where it is converted to benzoic acid and eliminated in the urine.

Drug Interactions

No formal drug-drug interaction studies were conducted with adapalene and benzoyl peroxide topical gel.