Clinical Pharmacology for Astepro
Mechanism Of Action
Azelastine hydrochloride, a phthalazinone derivative, exhibits histamine H1-receptor antagonist activity in isolated tissues, animal models, and humans. ASTEPRO is administered as a racemic mixture with no difference in pharmacologic activity noted between the enantiomers in in vitro studies. The major metabolite, desmethylazelastine, also possesses H1-receptor antagonist activity.
Pharmacodynamics
Cardiac Effects
In a placebo-controlled trial (95 patients with allergic rhinitis), there was no evidence of an effect of azelastine hydrochloride nasal spray (2 sprays per nostril twice daily for 56 days) on cardiac repolarization as represented by the corrected QT interval (QTc) of the electrocardiogram. Following multiple dose oral administration of azelastine 4 mg or 8 mg twice daily, the mean change in QTc was 7.2 msec and 3.6 msec, respectively.
Interaction studies investigating the cardiac repolarization effects of concomitantly administered oral azelastine hydrochloride and erythromycin or ketoconazole were conducted. Oral erythromycin had no effect on azelastine pharmacokinetics or QTc based on analysis of serial electrocardiograms. Ketoconazole interfered with the measurement of azelastine plasma levels; however, no effects on QTc were observed [see DRUG INTERACTIONS].
Pharmacokinetics
Absorption
After nasal administration of 2 sprays per nostril (548 mcg total dose) of ASTEPRO 0.1%, the mean azelastine peak plasma concentration (Cmax) is 200 pg/mL, the mean extent of systemic exposure (AUC) is 5122 pg•hr/mL and the median time to reach Cmax (tmax) is 3 hours. The systemic bioavailability of azelastine hydrochloride is approximately 40% after nasal administration.
Distribution
Based on intravenous and oral administration, the steady-state volume of distribution of azelastine is 14.5 L/kg. In vitro studies with human plasma indicate that the plasma protein binding of azelastine and its metabolite, desmethylazelastine, are approximately 88% and 97%, respectively.
Elimination
Following nasal administration of ASTEPRO 0.1%, the elimination half-life of azelastine is 22 hours while that of desmethylazelastine is 52 hours. Approximately 75% of an oral dose of radiolabeled azelastine hydrochloride was excreted in the feces with less than 10% as unchanged azelastine.
Metabolism
Azelastine is oxidatively metabolized to the principal active metabolite, desmethylazelastine, by the cytochrome P450 enzyme system. The specific P450 isoforms responsible for the biotransformation of azelastine have not been identified. After a single-dose, nasal administration of ASTEPRO 0.1% (548 mcg total dose), the mean desmethylazelastine Cmax is 23 pg/mL, the AUC is 2131 pg•hr/mL and the median tmax is 24 hours. After nasal dosing of azelastine to steady-state, plasma concentrations of desmethylazelastine range from 20-50% of azelastine concentrations.
Specific Populations
Patients With Hepatic Impairment
Following oral administration, pharmacokinetic parameters were not influenced by hepatic impairment.
Patients With Renal Impairment
Based on oral, single-dose studies, renal insufficiency (creatinine clearance < 50 mL/min) resulted in a 70-75% higher Cmax and AUC compared to healthy subjects. Time to maximum concentration was unchanged.
Age
Following oral administration, pharmacokinetic parameters were not influenced by age.
Male And Female Patients
Following oral administration, pharmacokinetic parameters were not influenced by gender.
Race
The effect of race has not been evaluated.
Drug Interaction Studies
Erythromycin
Co-administration of orally administered azelastine (4 mg twice daily) with erythromycin (500 mg three times daily for 7 days) resulted in Cmax of 5.36 ± 2.6 ng/mL and AUC of 49.7 ± 24 ng•h/mL for azelastine, whereas, administration of azelastine alone resulted in Cmax of 5.57 ± 2.7 ng/mL and AUC of 48.4 ± 24 ng•h/mL for azelastine [see DRUG INTERACTIONS].
Cimetidine And Ranitidine
In a multiple-dose, steady-state drug interaction trial in healthy subjects, cimetidine (400 mg twice daily) increased orally administered mean azelastine (4 mg twice daily) concentrations by approximately 65%. Co-administration of orally administered azelastine (4 mg twice daily) with ranitidine hydrochloride (150 mg twice daily) resulted in Cmax of 8.89 ±3.28 ng/mL and AUC of 88.22 ± 40.43 ng•h/mL for azelastine, whereas, administration of azelastine alone resulted in Cmax of 7.83 ± 4.06 ng/mL and AUC of 80.09 ± 43.55 ng•h/mL for azelastine [see DRUG INTERACTIONS].
Theophylline
No significant pharmacokinetic interaction was observed with the co-administration of an oral 4 mg dose of azelastine hydrochloride twice daily and theophylline 300 mg or 400 mg twice daily.
Clinical Studies
Seasonal Allergic Rhinitis
Adult And Adolescents 12 Years And Older
The efficacy and safety of ASTEPRO 0.1% was evaluated in a 2-week, randomized, multicenter, double-blind, placebo-controlled clinical trial including 834 adult and adolescent patients 12 years of age and older with symptoms of seasonal allergic rhinitis. The population was 12 to 83 years of age (60% female, 40% male; 69% white, 16% black, 12% Hispanic, 2% Asian, 1% other).
Patients were randomized to one of six treatment groups: 1 spray per nostril of either ASTEPRO 0.1%, Astelin (azelastine hydrochloride) Nasal Spray or vehicle placebo twice daily; or 2 sprays per nostril of ASTEPRO 0.1%, Astelin or vehicle placebo twice daily.
Assessment of efficacy was based on the 12-hour reflective total nasal symptom score (rTNSS) assessed daily in the morning and evening, in addition to the instantaneous total nasal symptom score (iTNSS) and other supportive secondary efficacy variables. TNSS is calculated as the sum of the patients’ scoring of the four individual nasal symptoms (rhinorrhea, nasal congestion, sneezing, and nasal itching) on a 0 to 3 categorical severity scale (0 = absent, 1 = mild, 2 = moderate, 3 = severe). The rTNSS required patients to record symptom severity over the previous 12 hours. For the primary efficacy endpoint, the mean change from baseline rTNSS, morning (AM) and evening (PM) rTNSS scores were summed for each day (maximum score of 24) and then averaged over the 2 weeks. The iTNSS, recorded immediately prior to the next dose, were assessed as an indication of whether the effect was maintained over the dosing interval.
In this trial, ASTEPRO 0.1% two sprays twice a day demonstrated a greater decrease in rTNSS and iTNSS than placebo and the difference was statistically significant. The trial results are presented in Table 4 (Trial 1).
The efficacy of ASTEPRO 0.1% one spray per nostril twice daily for seasonal allergic rhinitis is supported by two, 2-week, placebo-controlled clinical trials with Astelin (azelastine hydrochloride) Nasal Spray in 413 patients with seasonal allergic rhinitis. In these trials, efficacy was assessed using the TNSS (described above). Astelin demonstrated a greater decrease from baseline in the summed AM and PM rTNSS compared with placebo and the difference was statistically significant.
Pediatric Patients 6 Months To 5 Years Of Age
The efficacy of ASTEPRO 0.1% and ASTEPRO 0.15% in pediatric patients 6 months to 5 years of age with allergic rhinitis was explored in a 4-week, randomized, open-label safety trial in 191 patients. While the primary objective was to determine the safety of ASTEPRO in this age group, the study included an exploratory efficacy assessment of daily overall allergy symptom scores. Efficacy in children 6 months to 5 years of age was supported by a numerical decrease in the overall allergy symptom score in both treatment groups. There was no statistically significant difference between the two treatment groups.
Table 4: Mean Change from Baseline in Reflective TNSS over 2 Weeks* in Adults and Children ≥ 12 years with Seasonal Allergic Rhinitis
|
Treatment (sprays per nostril) |
n |
Baseline LS Mean |
Change from Baseline |
Difference From Placebo |
| LS Mean |
95% CI |
P value |
| Trial 1 |
| Two sprays twice daily |
ASTEPRO 0.1% |
146 |
18.0 |
-5.0 |
-2.2 |
-3.2, -1.2 |
<0.001 |
| Astelin Nasal Spray |
137 |
18.2 |
-4.2 |
-1.4 |
-2.4, -0.4 |
0.01 |
| Vehicle Placebo |
138 |
18.2 |
-2.8 |
|
| One spray twice daily |
ASTEPRO 0.1% |
139 |
18.2 |
-4.2 |
-0.7 |
-1.7, 0.3 |
0.18 |
| Astelin Nasal Spray |
137 |
18.1 |
-4.0 |
-0.4 |
-1.5, 0.6 |
0.41 |
| Vehicle Placebo |
137 |
18.0 |
-3.5 |
|
| *Sum of AM and PM rTNSS for each day (Maximum score=24) and averaged over the 14 day treatment period |
The efficacy and safety of ASTEPRO 0.1% in children 6 to 11 years of age with seasonal allergic rhinitis was evaluated in a clinical study that enrolled pediatric patients with perennial allergic rhinitis, with or without concomitant seasonal allergic rhinitis (described below in Section 14.2).
Perennial Allergic Rhinitis
Pediatric Patients 6 To 11 Years Of Age
The efficacy and safety of ASTEPRO 0.1% and ASTEPRO 0.15% in pediatric patients 6 to 11 years of age with perennial allergic rhinitis, with or without concomitant seasonal allergic rhinitis, was evaluated in a randomized, double-blind, placebo-controlled clinical trial in 486 patients. All patients received one spray per nostril twice daily. The study population was 58% males and 42% females; 78% white, 13% black, 3% Asian, and 6% other.
Assessment of efficacy was based on the 12-hour reflective total nasal symptom score (rTNSS) assessed daily in the morning and evening. The primary efficacy endpoint was the mean change from baseline rTNSS over 4 weeks (Table 7). Both active treatments demonstrated statistically significant decreases in rTNSS compared to placebo. There was no statistically significant difference between the two active-treatment groups. There was also no difference in treatment effect between patients with perennial allergic rhinitis only compared to those with perennial allergic rhinitis and concomitant seasonal allergic rhinitis.
Table 7: Mean Change from Baseline in Reflective TNSS over 4 Weeks* in Children 6 to 11 years with Perennial Allergic Rhinitis
|
Treatment (sprays per nostril twice daily) |
n |
Baseline LS Mean |
Change from Baseline |
Difference From Placebo |
| LS Mean |
95% CI |
P value |
| One spray twice daily |
ASTEPRO 0.15% |
159 |
16.6 |
-3.5 |
-1.0 |
-1.7, -0.3 |
0.005 |
| ASTEPRO 0.1% |
166 |
16.4 |
-3.4 |
-0.9 |
-1.6, -0.2 |
0.015 |
| Vehicle Placebo |
161 |
16.1 |
-2.5 |
|
| *Sum of AM and PM rTNSS for each day (Maximum score=24) and averaged over the 28 day treatment period |
The efficacy of ASTEPRO 0.1% in children 6 months to 5 years of age with allergic rhinitis was explored in a clinical study (described above in Section 14.1).