Desloratadine 5 mg Tablet, 100-count — NDC 72162-2308-1 (Billing 72162-2308-01)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Desloratadine is a long-acting tricyclic histamine antagonist with selective H 1 -receptor histamine antagonist activity. Receptor binding data indicates that at a concentration of 2-3 ng/mL (7 nanomolar), desloratadine shows significant interaction with the human histamine H 1 -receptor. Desloratadine inhibited histamine release from human mast cells in vitro .

Results of a radiolabeled tissue distribution study in rats and a radioligand H 1 -receptor binding study in guinea pigs showed that desloratadine did not readily cross the blood brain barrier. The clinical significance of this finding is unknown.

12.2Pharmacodynamics Wheal and Flare: Human histamine skin wheal studies following single and repeated 5-mg doses of desloratadine have shown that the drug exhibits an antihistaminic effect by 1 hour; this activity may persist for as long as 24 hours. There was no evidence of histamine-induced skin wheal tachyphylaxis within the desloratadine 5-mg group over the 28-day treatment period. The clinical relevance of histamine wheal skin testing is unknown.

Effects on QTc: Single daily doses of 45 mg were given to normal male and female volunteers for 10 days. All ECGs obtained in this study were manually read in a blinded fashion by a cardiologist. In Desloratadine-treated subjects, there was an increase in mean heart rate of 9.2 bpm relative to placebo.

The QT interval was corrected for heart rate (QTc) by both the Bazett and Fridericia methods. Using the QTc (Bazett) there was a mean increase of 8.1 msec in Desloratadine-treated subjects relative to placebo. Using QTc (Fridericia) there was a mean increase of 0.4 msec in Desloratadine-treated subjects relative to placebo.

No clinically relevant adverse events were reported.

12.3Pharmacokinetics Absorption Following oral administration of a desloratadine 5 mg tablet once daily for 10 days to normal healthy volunteers, the mean time to maximum plasma concentrations (T max ) occurred at approximately 3 hours post dose and mean steady state peak plasma concentrations (C max ) and AUC of 4 ng/mL and 56.9 ng∙hr/mL were observed, respectively. Neither food nor grapefruit juice had an effect on the bioavailability (C max and AUC) of desloratadine. The pharmacokinetic profile of Desloratadine Oral Solution was evaluated in a three-way crossover study in 30 adult volunteers.

A single dose of 10 mL of Desloratadine Oral Solution containing 5 mg of desloratadine was bioequivalent to a single dose of 5 mg Desloratadine Tablet. Food had no effect on the bioavailability (AUC and C max ) of Desloratadine Oral Solution. Distribution Desloratadine and 3-hydroxydesloratadine are approximately 82% to 87% and 85% to 89% bound to plasma proteins, respectively.

Protein binding of desloratadine and 3-hydroxydesloratadine was unaltered in subjects with impaired renal function. Metabolism Desloratadine (a major metabolite of loratadine) is extensively metabolized to 3-hydroxydesloratadine, an active metabolite, which is subsequently glucuronidated. The enzyme(s) responsible for the formation of 3-hydroxydesloratadine have not been identified.

Data from clinical trials indicate that a subset of the general population has a decreased ability to form 3-hydroxydesloratadine, and are poor metabolizers of desloratadine. In pharmacokinetic studies (n=3748), approximately 6% of subjects were poor metabolizers of desloratadine (defined as a subject with an AUC ratio of 3-hydroxydesloratadine to desloratadine less than 0.1, or a subject with a desloratadine half-life exceeding 50 hours). These pharmacokinetic studies included subjects between the ages of 2 and 70 years, including 977 subjects aged 2 to 5 years, 1575 subjects aged 6 to 11 years, and 1196 subjects aged 12 to 70 years.

There was no difference in the prevalence of poor metabolizers across age groups. The frequency of poor metabolizers was higher in Blacks (17%, n=988) as compared to Caucasians (2%,… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action Desloratadine is a long-acting tricyclic histamine antagonist with selective H 1 -receptor histamine antagonist activity. Receptor binding data indicates that at a concentration of 2-3 ng/mL (7 nanomolar), desloratadine shows significant interaction with the human histamine H 1 -receptor. Desloratadine inhibited histamine release from human mast cells in vitro .

Results of a radiolabeled tissue distribution study in rats and a radioligand H 1 -receptor binding study in guinea pigs showed that desloratadine did not readily cross the blood brain barrier. The clinical significance of this finding is unknown.

12.3Pharmacokinetics Absorption Following oral administration of a desloratadine 5 mg tablet once daily for 10 days to normal healthy volunteers, the mean time to maximum plasma concentrations (T max ) occurred at approximately 3 hours post dose and mean steady state peak plasma concentrations (C max ) and AUC of 4 ng/mL and 56.9 ng∙hr/mL were observed, respectively. Neither food nor grapefruit juice had an effect on the bioavailability (C max and AUC) of desloratadine. The pharmacokinetic profile of Desloratadine Oral Solution was evaluated in a three-way crossover study in 30 adult volunteers.

A single dose of 10 mL of Desloratadine Oral Solution containing 5 mg of desloratadine was bioequivalent to a single dose of 5 mg Desloratadine Tablet. Food had no effect on the bioavailability (AUC and C max ) of Desloratadine Oral Solution. Distribution Desloratadine and 3-hydroxydesloratadine are approximately 82% to 87% and 85% to 89% bound to plasma proteins, respectively.

Protein binding of desloratadine and 3-hydroxydesloratadine was unaltered in subjects with impaired renal function. Metabolism Desloratadine (a major metabolite of loratadine) is extensively metabolized to 3-hydroxydesloratadine, an active metabolite, which is subsequently glucuronidated. The enzyme(s) responsible for the formation of 3-hydroxydesloratadine have not been identified.

Data from clinical trials indicate that a subset of the general population has a decreased ability to form 3-hydroxydesloratadine, and are poor metabolizers of desloratadine. In pharmacokinetic studies (n=3748), approximately 6% of subjects were poor metabolizers of desloratadine (defined as a subject with an AUC ratio of 3-hydroxydesloratadine to desloratadine less than 0.1, or a subject with a desloratadine half-life exceeding 50 hours). These pharmacokinetic studies included subjects between the ages of 2 and 70 years, including 977 subjects aged 2 to 5 years, 1575 subjects aged 6 to 11 years, and 1196 subjects aged 12 to 70 years.

There was no difference in the prevalence of poor metabolizers across age groups. The frequency of poor metabolizers was higher in Blacks (17%, n=988) as compared to Caucasians (2%, n=1,462) and Hispanics (2%, n=1,063). The median exposure (AUC) to desloratadine in the poor metabolizers was approximately 6-fold greater than in the subjects who are not poor metabolizers.

Subjects who are poor metabolizers of desloratadine cannot be prospectively identified and will be exposed to higher levels of desloratadine following dosing with the recommended dose of desloratadine. In multidose clinical safety studies, where metabolizer status was identified, a total of 94 poor metabolizers and 123 normal metabolizers were enrolled and treated with Desloratadine Oral Solution for 15-35 days. In these studies, no overall differences in safety were observed between poor metabolizers and normal metabolizers.

Although not seen in these studies, an increased risk of exposure-related adverse events in patients who are poor metabolizers cannot be ruled out. Elimination The mean plasma elimination half-life of desloratadine was approximately 27 hours. C max and AUC values increased in a dose proportional manner following single oral doses between 5 and 20 mg.

The degree of accumulation after 14 days of dosing was consistent with the half-life and dosing frequency. A human mass balance study documented a recovery of approximately 87% of the 14C-desloratadine dose, which was equally distributed in urine and feces as metabolic products. Analysis of plasma 3-hydroxydesloratadine showed similar T max and half-life values compared to desloratadine.

Special Populations Geriatric Subjects: In older subjects (≥65 years old; n=17) following multiple-dose administration of Desloratadine Tablets, the mean C max and AUC values for desloratadine were 20% greater than in younger subjects (<65 years old). The oral total body clearance (CL/F) when normalized for body weight was similar betw… [Excerpted — this section continues on DailyMed.]

12.2Pharmacodynamics Wheal and Flare: Human histamine skin wheal studies following single and repeated 5-mg doses of desloratadine have shown that the drug exhibits an antihistaminic effect by 1 hour; this activity may persist for as long as 24 hours. There was no evidence of histamine-induced skin wheal tachyphylaxis within the desloratadine 5-mg group over the 28-day treatment period. The clinical relevance of histamine wheal skin testing is unknown.

Effects on QTc: Single daily doses of 45 mg were given to normal male and female volunteers for 10 days. All ECGs obtained in this study were manually read in a blinded fashion by a cardiologist. In Desloratadine-treated subjects, there was an increase in mean heart rate of 9.2 bpm relative to placebo.

The QT interval was corrected for heart rate (QTc) by both the Bazett and Fridericia methods. Using the QTc (Bazett) there was a mean increase of 8.1 msec in Desloratadine-treated subjects relative to placebo. Using QTc (Fridericia) there was a mean increase of 0.4 msec in Desloratadine-treated subjects relative to placebo.

No clinically relevant adverse events were reported.

14 CLINICAL STUDIES

14.1Seasonal Allergic Rhinitis The clinical efficacy and safety of Desloratadine Tablets were evaluated in over 2300 patients 12 to 75 years of age with seasonal allergic rhinitis. A total of 1838 patients received 2.5 to 20 mg/day of Desloratadine in 4 double-blind, randomized, placebo-controlled clinical trials of 2 to 4 weeks' duration conducted in the United States. The results of these studies demonstrated the efficacy and safety of Desloratadine 5 mg in the treatment of adult and adolescent patients with seasonal allergic rhinitis.

In a dose-ranging trial, Desloratadine 2.5 to 20 mg/day was studied. Doses of 5, 7.5, 10, and 20 mg/day were superior to placebo; and no additional benefit was seen at doses above 5.0 mg. In the same study, an increase in the incidence of somnolence was observed at doses of 10 mg/day and 20 mg/day (5.2% and 7.6%, respectively), compared to placebo (2.3%).

In two 4-week studies of 924 patients (aged 15 to 75 years) with seasonal allergic rhinitis and concomitant asthma, Desloratadine Tablets 5 mg once daily improved rhinitis symptoms, with no decrease in pulmonary function. This supports the safety of administering Desloratadine Tablets to adult patients with seasonal allergic rhinitis with mild to moderate asthma. Desloratadine Tablets 5 mg once daily significantly reduced the Total Symptom Score (the sum of individual scores of nasal and non-nasal symptoms) in patients with seasonal allergic rhinitis.

See Table 3 . Table 3 TOTAL SYMPTOM SCORE (TSS) Changes in a 2 Week Clinical Trial in Patients with Seasonal Allergic Rhinitis Treatment Group (n) Mean Baseline At baseline, a total nasal symptom score (sum of 4 individual symptoms) of at least 6 and a total non-nasal symptom score (sum of 4 individual symptoms) of at least 5 (each symptom scored 0 to 3 where 0=no symptom and 3=severe symptoms) was required for trial eligibility. TSS ranges from 0=no symptoms to 24=maximal symptoms.

(SEM) Change from Baseline Mean reduction in TSS averaged over the 2-week treatment period. (SEM) Placebo Comparison ( P -value) SEM = Standard Error of the Mean Desloratadine 5.0 mg (171) 14.2 (0.3) -4.3 (0.3) P <0.01 Placebo (173) 13.7 (0.3) -2.5 (0.3) There were no significant differences in the effectiveness of Desloratadine Tablets 5 mg across subgroups of patients defined by gender, age, or race.

14.2Perennial Allergic Rhinitis The clinical efficacy and safety of Desloratadine Tablets 5 mg were evaluated in over 1300 patients 12 to 80 years of age with perennial allergic rhinitis. A total of 685 patients received 5 mg/day of Desloratadine in two double-blind, randomized, placebo-controlled clinical trials of 4 weeks' duration conducted in the United States and internationally. In one of these studies Desloratadine Tablets 5 mg once daily was shown to significantly reduce the Total Symptom Score in patients with perennial allergic rhinitis (Table 4).

Table 4 TOTAL SYMPTOM SCORE (TSS) Changes in a 4 Week Clinical Trial in Patients with Perennial Allergic Rhinitis Treatment Group (n) Mean Baseline At baseline, average of total symptom score (sum of 5 individual nasal symptoms and 3 non-nasal symptoms, each symptom scored 0 to 3 where 0=no symptom and 3=severe symptoms) of at least 10 was required for trial eligibility. TSS ranges from 0=no symptoms to 24=maximal symptoms. (SEM) Change from Baseline Mean reduction in TSS averaged over the 4 week treatment period.

(SEM) Placebo Comparison ( P -value) SEM = Standard Error of the Mean Desloratadine 5.0 mg (337) 12.37 (0.18) -4.06 (0.21) P =0.01 Placebo (337) 12.30 (0.18) -3.27 (0.21)

14.3Chronic Idiopathic Urticaria The efficacy and safety of Desloratadine Tablets 5 mg once daily was studied in 416 chronic idiopathic urticaria patients 12 to 84 years of age, of whom 211 received Desloratadine. In two double-blind, placebo-controlled, randomized clinical trials of six weeks duration, at the pre-specified one-week primary time point evaluation, De… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenicity Studies The carcinogenic potential of desloratadine was assessed using a loratadine study in rats and a desloratadine study in mice. In a 2-year study in rats, loratadine was administered in the diet at doses up to 25 mg/kg/day (approximately 45 times the summed AUC-based exposure of desloratadine and its metabolite at the RHD). A significantly higher incidence of hepatocellular tumors (combined adenomas and carcinomas) was observed in males given 10 mg/kg/day of loratadine (approximately 10 times the summed AUC-based exposure of desloratadine and its metabolite at the RHD) and in males and females given 25 mg/kg/day of loratadine.

The clinical significance of these findings during long-term use of desloratadine is not known. In a 2-year dietary study in mice, males and females given up to 16 mg/kg/day and 32 mg/kg/day desloratadine, respectively (approximately 30 and 70 times the summed AUC-based exposure of desloratadine and its metabolite at the RHD, respectively), did not show significant increases in the incidence of any tumors. Genotoxicity Studies In genotoxicity studies with desloratadine, there was no evidence of genotoxic potential in a reverse mutation assay ( Salmonella/E. coli mammalian microsome bacterial mutagenicity assay) or in 2 assays for chromosomal aberrations (human peripheral blood lymphocyte clastogenicity assay and mouse bone marrow micronucleus assay).

Impairment of Fertility In a female fertility study, desloratadine was given to female rats orally 14 days prior to and throughout mating until Gestation Day 7 at doses of 6, 12 and 24 mg/kg/day. An increase in preimplantation loss and a decrease in number of implantations and fetuses noted at 24 mg/kg (approximately 200 times the summed AUC-based exposure of desloratadine and its metabolite at the RHD) was likely due to maternal toxicities including reduced body weight gain and food consumption. In a male fertility study in rats, desloratadine was given orally to male rats for 70 days prior to mating and throughout the mating period (total dosing period 106-108 days) at doses of 3, 12 and 40 mg/kg/day.

Reduced body weight gain, food consumption, and absolute organ weights of testes, epididymis, and cauda epididymis were noted at 40 mg/kg/day. A male-specific decrease in fertility, demonstrated by reduced female conception rates, decreased sperm numbers and motility, and histopathologic changes in testes and epididymis, occurred at a dose of 12 mg/kg or greater (approximately 65 times or greater than the summed AUC-based exposure of desloratadine and its metabolite at the RHD). Desloratadine had no effect on male fertility in rats at 3 mg/kg/day (approximately 10 times the summed AUC-based exposure of desloratadine and its metabolite at the RHD).