Azelaic Acid

Azelaic acid gel, 15% is indicated for topical treatment of the inflammatory papules and pustules of mild to moderate rosacea.

Although some reduction of erythema which was present in patients with papules and pustules of rosacea occurred in clinical studies, efficacy for treatment of erythema in rosacea in the absence of papules and pustules has not been evaluated.

• Cleanse affected area(s) using only very mild soaps or soapless cleansing lotion and pat dry with a soft towel before application of azelaic acid gel.
• Apply and gently massage a thin layer of azelaic acid gel into the affected areas on the face twice daily (morning and evening).
• Wash hands immediately following application of azelaic acid gel.
• Cosmetics may be applied after the application of azelaic acid gel has dried.
• Reassess the diagnosis if no improvement is observed upon completing 12 weeks of therapy.
• Avoid the use of occlusive dressings or wrappings.
• Instruct patients to avoid use of alcoholic cleansers, tinctures and astringents, abrasives and peeling agents.
• For topical use.
• Not for oral, ophthalmic or intravaginal use.

Azelaic acid gel, 15% is a white to off-white homogeneous gel. Each gram of azelaic acid gel contains 0.15 gm of azelaic acid (15% w/w).

Azelaic acid gel 15%, is an aqueous gel which contains azelaic acid, a naturally-occurring saturated dicarboxylic acid. It is for topical use. Chemically, azelaic acid is 1,7-heptanedicarboxylic acid. The molecular formula for azelaic acid is C₉H₁₆O₄. It has the following structure:

Azelaic acid has a molecular weight of 188.22. It is a white, odorless crystalline solid. It is poorly soluble in water at 20°C (0.24%) but freely soluble in boiling water and in ethanol.

Azelaic acid gel 15%, is a white to off-white homogeneous gel for topical use; each gram contains 0.15 gm azelaic acid (15% w/w) in an aqueous gel base containing benzoic acid (as a preservative), carbopol 980, edetate disodium, glycerol monooleate, lecithin, polysorbate 80, propylene glycol, purified water, and sodium hydroxide to adjust pH.

Azelaic acid gel was evaluated for the treatment of mild to moderate papulopustular rosacea in two multicenter, randomized, double-blind, vehicle-controlled, 12-week clinical trials having identical protocols and involving a total of 664 (active: 333; vehicle: 331) subjects aged 21 to 86 years (mean age = 49). Overall, 92.5% of subjects were Caucasian and 73% of subjects were female. Enrolled subjects had mild to moderate rosacea with a mean lesion count of 18 (range 8 to 60) inflammatory papules and pustules. The following subjects were excluded: a) those without papules and pustules; b) those with nodules, rhinophyma, or ocular involvement and c) those with a history of hypersensitivity to propylene glycol or to any other ingredients of the study drug. Azelaic acid gel or its vehicle were to be applied twice daily for 12 weeks; no other topical or systemic medication affecting the course of rosacea and/or evaluability was to be used during the studies. Subjects were instructed to avoid spicy foods, thermally hot food/drink and alcoholic beverages during the study. Subjects were also instructed to use only very mild soaps or soapless cleansing lotion for facial cleansing.

The primary efficacy endpoints included both 1) change from baseline in inflammatory lesion counts as well as 2) success defined as a score of “clear” or “minimal” with at least a 2-step reduction from baseline on the Investigator’s Global Assessment (IGA), defined as follows below:

CLEAR:

No papules and/or pustules; no or residual erythema; no or mild to moderate telangiectasia

MINIMAL:

Rare papules and/or pustules; residual to mild erythema; mild to moderate telangiectasia

MILD:

Few papules and/or pustules; mild erythema; mild to moderate telangiectasia

MILD TO MODERATE:

Distinct number of papules and/or pustules; mild to moderate erythema; mild to moderate telangiectasia

MODERATE:

Pronounced number of papules and/or pustules; moderate erythema; mild to moderate telangiectasia

MODERATE TO SEVERE:

Many papules and/or pustules, occasionally with large inflamed lesions; moderate erythema; moderate degree of telangiectasia

SEVERE:

Numerous papules and/or pustules, occasionally with confluent areas of inflamed lesions; moderate or severe erythema; moderate or severe telangiectasia

Primary efficacy assessment was based on the “intent-to-treat” (ITT) population with the “last observation carried forward” (LOCF).

Both trials demonstrated a statistically significant difference in favor of azelaic acid gel over its vehicle in both reducing the number of inflammatory papules and pustules associated with rosacea (Table 2) as well as demonstrating success on the IGA in the ITT-LOCF population at the end of treatment.

Although some reduction of erythema which was present in subjects with papules and pustules of rosacea occurred in clinical trials, efficacy for treatment of erythema in rosacea in the absence of papules and pustules has not been evaluated.

Azelaic acid gel was superior to the vehicle with regard to success based on the IGA of rosacea on a 7-point static score at the end of treatment (ITT population; Table 3).