5.1 Hypersensitivity

Hypersensitivity reactions, including cases of angioedema, eye swelling, facial swelling, dyspnea, urticaria, and adverse skin reactions, have been reported during post marketing surveillance.

Avoid the use of azelaic acid gel in patients with known hypersensitivity to any component of the gel. If hypersensitivity develops during treatment, discontinue azelaic acid gel and institute appropriate therapy.

5.2 Skin Reactions

Skin irritation (i.e. pruritus, burning or stinging) may occur during use of azelaic acid gel, usually during the first few weeks of treatment. If sensitivity or severe irritation develops and persists, discontinue treatment and institute appropriate therapy.

There have been isolated reports of hypopigmentation after use of azelaic acid. Since azelaic acid has not been well studied in patients with dark complexion, monitor these patients for early signs of hypopigmentation.

5.3 Eye and Mucous Membranes Irritation

Azelaic acid gel has been reported to cause irritation of the eyes. Avoid contact with the eyes, mouth and other mucous membranes. If azelaic acid gel comes in contact with the eyes, wash the eyes with large amounts of water and consult a physician if eye irritation persists [see Adverse Reactions (6.2)].

5.4 Exacerbation of Asthma

Worsening of asthma has been reported in patients using azelaic acid formulations including azelaic acid gel. Consult a physician if asthma is exacerbated with use of azelaic acid gel.

6.1 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 practice.

In two vehicle-controlled and one active-controlled U.S. clinical trials, treatment safety was monitored in 788 subjects who used twice-daily azelaic acid gel for 12 weeks (N=333) or 15 weeks (N=124), or the gel vehicle (N=331) for 12 weeks. In all three trials, the most common treatment-related adverse events were: burning/stinging/tingling (29%), pruritus (11%), scaling/dry skin/xerosis (8%) and erythema/irritation (4%). In the active-controlled trial, overall adverse reactions (including burning, stinging/tingling, dryness/tightness/scaling, itching, and erythema/irritation/redness) were 19.4% (24/124) for azelaic acid gel compared to 7.1% (9/127) for the active comparator gel at 15 weeks.

In patients using azelaic acid formulations, the following adverse events have been reported: worsening of asthma, vitiligo, depigmentation, small depigmented spots, hypertrichosis, reddening (signs of keratosis pilaris) and exacerbation of recurrent herpes labialis.

Local Tolerability Studies

Azelaic acid gel and its vehicle caused irritant reactions at the application site in human dermal safety studies. Azelaic acid gel caused significantly more irritation than its vehicle in a cumulative irritation study. Some improvement in irritation was demonstrated over the course of the clinical trials, but this improvement might be attributed to subject dropouts. No phototoxicity or photoallergenicity were reported in human dermal safety studies.

6.2 Postmarketing Experience

The following adverse reactions have been identified post approval of azelaic acid gel. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate the frequency or establish a causal relationship to drug exposure:

Eyes: iridocyclitis upon accidental exposure of the eyes to azelaic acid gel.

Hypersensitivity: angioedema, eye swelling, facial swelling, urticaria.

Respiratory: worsening of asthma, dyspnea, wheezing.

Skin reactions: application site rash.

8.1 Pregnancy

Risk Summary

Azelaic acid is minimally absorbed systemically following topical route of administration, and maternal use is not expected to result in fetal exposure to the drug [see Clinical Pharmacology (12.3)].

In animal reproduction studies, embryofetal toxicity was noted when azelaic acid was administered orally during the period of organogenesis at doses 162, 19, and 65 times the maximum recommended human dose (MRHD) in rats, rabbits, and monkeys, respectively. Maternal toxicity was noted at these doses but no malformations were observed in these embryofetal developmental studies (see Data).

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

Data

Animal Data

Dermal embryofetal developmental toxicology studies have not been performed with azelaic acid, 15% gel. Oral embryofetal developmental studies were conducted with azelaic acid in rats, rabbits, and cynomolgus monkeys. Azelaic acid was administered during the period of organogenesis in all three animal species. Embryotoxicity was observed in rats, rabbits, and monkeys at oral doses of azelaic acid that generated some maternal toxicity. Embryotoxicity was observed in rats given 2500 mg/kg/day [162 times the MRHD based on body surface area (BSA) comparison], rabbits given 150 or 500 mg/kg/day (19 or 65 times the MRHD based on BSA comparison) and cynomolgus monkeys given 500 mg/kg/day (65 times the MRHD based on BSA comparison) azelaic acid. No malformations were observed in the oral embryofetal developmental studies conducted in rats, rabbits and cynomolgus monkeys.

An oral peri- and post-natal developmental study was conducted in rats. Azelaic acid was administered from gestational day 15 through day 21 postpartum up to a dose level of 2500 mg/kg/day. Embryotoxicity was observed in rats at an oral dose of 2500 mg/kg/day (162 times the MRHD based on BSA comparison) that generated some maternal toxicity. In addition, slight disturbances in the post-natal development of fetuses was noted in rats at oral doses that generated some maternal toxicity (500 and 2500 mg/kg/day; 32 and 162 times the MRHD based on BSA comparison). No effects on sexual maturation of the fetuses were noted in this study.

8.2 Lactation

Risk Summary

Azelaic acid is naturally present in human milk. When used as prescribed, azelaic acid is unlikely to be absorbed through the skin in clinically relevant amounts to cause a change in azelaic acid concentration in milk or milk production; therefore, breastfeeding is not expected to result in exposure of the infant to azelaic acid gel. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for azelaic acid gel and any potential adverse effects on the breastfed child from azelaic acid gel or from the underlying maternal condition.

8.4 Pediatric Use

The safety and effectiveness of azelaic acid gel have not been established in pediatric patients.

8.5 Geriatric Use

Clinical studies of azelaic acid gel did not include sufficient numbers of subjects aged 65 and over to determine if they respond differently than younger subjects.

12.1 Mechanism of Action

The mechanism(s) by which azelaic acid interferes with the pathogenic events in rosacea are unknown.

12.2 Pharmacodynamics

The pharmacodynamics of azelaic acid in association with the treatment of rosacea are unknown.

12.3 Pharmacokinetics

The percutaneous absorption of azelaic acid after topical application of azelaic acid gel could not be reliably determined. Mean plasma azelaic acid concentrations in rosacea subjects treated with azelaic acid gel twice daily for at least 8 weeks are in the range of 42 to 63.1 ng/mL. These values are within the maximum concentration range of 24.0 to 90.5 ng/mL observed in rosacea subjects treated with vehicle only. This indicates that azelaic acid gel does not increase plasma azelaic acid concentration beyond the range derived from nutrition and endogenous metabolism.

In vitro and human data suggest negligible cutaneous metabolism of 3H-azelaic acid after topical application of 20% azelaic acid cream. Azelaic acid is mainly excreted unchanged in the urine, but undergoes some ß-oxidation to shorter chain dicarboxylic acids.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

In a 2-year dermal mouse carcinogenicity study, azelaic acid pre-foam emulsion was administered twice daily to CD-1 mice at topical doses of 5%, 15%, and 30% (500, 1500, and 3000 mg/kg/day azelaic acid). No drug-related tumors were noted at concentrations up to 30% azelaic acid (396 times the MRHD based on AUC comparison).

Azelaic acid was not mutagenic or clastogenic in a battery of in vitro [Ames assay, HGPRT in V79 cells (Chinese hamster lung cells), and chromosomal aberration assay in human lymphocytes] and in vivo (dominant lethal assay in mice and mouse micronucleus assay) genotoxicity tests.

Oral administration of azelaic acid at dose levels up to 2500 mg/kg/day (162 times the MRHD based on BSA comparison) did not affect fertility or reproductive performance in male or female rats.