Emedastine patch shows potential in management of allergic rhinitis
Transdermal administration of emedastine difumarate provides effective control of symptoms of seasonal allergic rhinitis, with the effects sustained throughout the day and raising no safety signals of clinical concern, according to the results of a phase III trial.
The trial randomized 1,276 adult patients to receive a transdermal patch containing emedastine 4 mg (n=384) or 8 mg (n=382), placebo (n=384), or oral levocetirizine 5 mg (reference drug; n=126) once daily for 2 weeks.
At week 2, emedastine demonstrated superior efficacy over placebo for allergic rhinitis symptoms. The primary outcome of change from baseline in the total nasal symptom score (TNSS) was significantly greater in both the 4- and 8-mg emedastine patch groups (−1.22 and −1.50, respectively, vs −0.45 with placebo; p<0.0001). [Allergol Int 2018;doi:10.1016/j.alit.2017.12.005]
In a secondary analysis, the 8-mg emedastine patch yielded the greatest reduction in TNSS, followed by levocetirizine, the 4-mg patch and placebo (−1.49, −1.32, −1.20 and −0.44, respectively). This suggests that the 8-mg emedastine patch might be as effective as or superior to levocetirizine monotherapy, which was reportedly more effective than loratadine for allergic rhinitis, the investigators said. [Allergol Int 2011;60:541-546]
Changes in the number of episodes of sneezing and nose blowing, and nasal congestion score were significantly larger throughout the day in both emedastine patch groups than in the placebo group (p<0.05 for all). The reduction in sneezing and nose blowing episodes was especially evident at night (from 18:00 to awakening on the next day) with the 8-mg emedastine patch.
“With regard to evaluation of the continuity of effect, the percentage of patients who felt the drug lost efficacy during a day of treatment … was lower in the emedastine patch groups [27.6 percent with the 4-mg patch; 26.3 percent with the 8-mg patch] than in the levocetirizine group [34.9 percent]. This suggests that consistent transdermal drug delivery maintained a stable blood concentration and sustained drug activity until the next application in the emedastine groups,” the investigators said.
There were no reports of clinically significant safety problems. The incidence rate of adverse events (AEs) was 13.8 percent in the 4-mg patch group, 18.1 percent in the 8-mg patch group, 15.4 percent in the placebo group and 13.5 percent in the levocetirizine group. Commonly reported AEs included application site erythema, application site pruritus, increased gamma-glutamyltransferase and somnolence. AEs resulting in study withdrawal only occurred in the placebo group.
The present data demonstrate that emedastine patch 4 mg and 8 mg may effectively and safely control symptoms of seasonal allergic rhinitis, with the patches showing sustained action throughout the daytime and night-time, according to the investigators. “This may be attributable to the feature of the slower increase of the plasma drug concentration and the more consistent plasma concentration with patch formulations compared to oral formulations.” [Drugs Aging 2006;23:357-375; Br J Pharmacol 2015;172:2179-2209]
In line with the International Council for Harmonisation E11 guideline stating the need to develop alternative delivery systems for paediatric formulations, the investigators also pointed out that the use of emedastine patch may improve adherence in children with allergic rhinitis. This is because the taste of oral liquid formulations can influence adherence and there is a risk of incomplete ingestion.
The transdermal preparation of emedastine should thus be investigated for the treatment of paediatric allergic rhinitis in the future, they added.