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,15% 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, 15% compared to 7.1% (9/127) for the active comparator gel at 15 weeks.
Table 1: Adverse Events Occurring in ≥1% of Subjects in the Rosacea Trials by Treatment Group and Maximum Intensity*!
| *Subjects may have >1 cutaneous adverse event; thus, the sum of the frequencies of preferred terms may exceed the number of subjects with at least 1 cutaneous adverse event.! |
| Azelaic acid gel, 15% N=457 (100%) | Vehicle N=331 (100%) |
Mild N=99 (22%) | Moderate N=61 (13%) | Severe N=27 (6%) | Mild N=46 (14%) | Moderate N=30 (9%) | Severe N=5 (2%) |
Burning/stinging/tingling | 71 (16%) | 42 (9%) | 17 (4%) | 8 (2%) | 6 (2%) | 2 (1%) |
Pruritus | 29 (6%) | 18 (4%) | 5 (1%) | 9 (3%) | 6 (2%) | 0 (0%) |
Scaling/dry skin/xerosis | 21 (5%) | 10 (2%) | 5 (1%) | 31 (9%) | 14 (4%) | 1 (<1%) |
Erythema/irritation | 6 (1%) | 7 (2%) | 2 (<1%) | 8 (2%) | 4 (1%) | 2 (1%) |
Contact dermatitis | 2 (<1%) | 3 (1%) | 0 (0%) | 1 (<1%) | 0 (0%) | 0 (0%) |
Edema | 3 (1%) | 2 (<1%) | 0 (0%) | 3 (1%) | 0 (0%) | 0 (0%) |
Acne | 3 (1%) | 1 (<1%) | 0 (0%) | 1 (<1%) | 0 (0%) | 0 (0%) |
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, 15% and its vehicle caused irritant reactions at the application site in human dermal safety studies. Azelaic Acid Gel, 15% 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.