2.1       Dose

      One GRASTEK tablet daily.

2.2       Administration

      Administer the first dose of GRASTEK in a healthcare setting under the supervision of a physician with experience in the diagnosis and treatment of allergic diseases. After receiving the first dose of GRASTEK, observe the patient for at least 30 minutes to monitor for signs or symptoms of a severe systemic or a severe local allergic reaction. If the patient tolerates the first dose, the patient may take subsequent doses at home.

      Administer GRASTEK to children under adult supervision.

Take the tablet from the blister unit after carefully removing the foil with dry hands.

Place the tablet immediately under the tongue. Allow it to remain there until completely dissolved. Do not swallow for at least 1 minute.

Wash hands after handling the tablet.

Do not take the tablet with food or beverage. Food or beverage should not be taken for the following 5 minutes after taking the tablet.

      Initiate treatment at least 12 weeks before the expected onset of each grass pollen season and continue treatment throughout the season. For sustained effectiveness for one grass pollen season after cessation of treatment, GRASTEK may be taken daily for three consecutive years (including the intervals between the grass pollen seasons). The safety and efficacy of initiating treatment in season have not been established.

      Data regarding the safety of restarting treatment after missing a dose of GRASTEK are limited. In the clinical trials, treatment interruptions for up to seven days were allowed.

      Prescribe auto-injectable epinephrine to patients prescribed GRASTEK and instruct them in the proper use of emergency self-injection of epinephrine [see Warnings and Precautions (5.2)].

5.1       Severe Allergic Reactions

      GRASTEK can cause systemic allergic reactions including anaphylaxis which may be life-threatening. In addition, GRASTEK can cause severe local reactions, including laryngopharyngeal swelling, which can compromise breathing and be life-threatening. Educate patients to recognize the signs and symptoms of these allergic reactions and instruct them to seek immediate medical care and discontinue therapy should any of these occur. Allergic reactions may require treatment with epinephrine. [See Warnings and Precautions (5.2).]

      Administer the initial dose of GRASTEK in a healthcare setting under the supervision of a physician with experience in the diagnosis and treatment of allergic diseases and prepared to manage a life-threatening systemic or local allergic reaction. Observe patients in the office for at least 30 minutes following the initial dose of GRASTEK.

5.2       Epinephrine

      Prescribe auto-injectable epinephrine to patients receiving GRASTEK. Instruct patients to recognize the signs and symptoms of a severe allergic reaction and in the proper use of emergency auto-injectable epinephrine. Instruct patients to seek immediate medical care upon use of auto-injectable epinephrine and to stop treatment with GRASTEK. [See Patient Counseling Information (17).]

      See the epinephrine package insert for complete information.

      GRASTEK may not be suitable for patients with certain medical conditions that may reduce the ability to survive a serious allergic reaction or increase the risk of adverse reactions after epinephrine administration. Examples of these medical conditions include but are not limited to: markedly compromised lung function (either chronic or acute), unstable angina, recent myocardial infarction, significant arrhythmia, and uncontrolled hypertension.

      GRASTEK may not be suitable for patients who are taking medications that can potentiate or inhibit the effect of epinephrine. These medications include:

Βeta-adrenergic blockers: Patients taking beta-adrenergic blockers may be unresponsive to the usual doses of epinephrine used to treat serious systemic reactions, including anaphylaxis. Specifically, beta-adrenergic blockers antagonize the cardiostimulating and bronchodilating effects of epinephrine.

Alpha-adrenergic blockers, ergot alkaloids: Patients taking alpha-adrenergic blockers may be unresponsive to the usual doses of epinephrine used to treat serious systemic reactions, including anaphylaxis. Specifically, alpha-adrenergic blockers antagonize the vasoconstricting and hypertensive effects of epinephrine. Similarly, ergot alkaloids may reverse the pressor effects of epinephrine.

Tricyclic antidepressants, levothyroxine sodium, monoamine oxidase inhibitors and certain antihistamines: The adverse effects of epinephrine may be potentiated in patients taking tricyclic antidepressants, levothyroxine sodium, monoamine oxidase inhibitors, and the antihistamines chlorpheniramine, and diphenhydramine.

Cardiac glycosides, diuretics: Patients who receive epinephrine while taking cardiac glycosides or diuretics should be observed carefully for the development of cardiac arrhythmias.

5.3       Upper Airway Compromise

      GRASTEK can cause local reactions in the mouth or throat that could compromise the upper airway [see Adverse Reactions (6.1 and 6.2)]. Consider discontinuation of GRASTEK in patients who experience persistent and escalating adverse reactions in the mouth or throat.

5.4       Eosinophilic Esophagitis

      Eosinophilic esophagitis has been reported in association with sublingual tablet immunotherapy [see Contraindications (4) and Adverse Reactions (6.2)]. Discontinue GRASTEK and consider a diagnosis of eosinophilic esophagitis in patients who experience severe or persistent gastro-esophageal symptoms including dysphagia or chest pain.

5.5       Asthma

      GRASTEK has not been studied in subjects with moderate or severe asthma or any subjects who required daily medication to treat asthma.

      Withhold immunotherapy with GRASTEK if the patient is experiencing an acute asthma exacerbation. Reevaluate patients who have recurrent asthma exacerbations and consider discontinuation of GRASTEK.

5.6       Concomitant Allergen Immunotherapy

      GRASTEK has not been studied in subjects who are receiving concomitant allergen immunotherapy. Concomitant dosing with other allergen immunotherapy may increase the likelihood of local or systemic adverse reactions to either subcutaneous or sublingual allergen immunotherapy.

5.7       Oral Inflammation

      Stop treatment with GRASTEK to allow complete healing of the oral cavity in patients with oral inflammation (e.g., oral lichen planus, mouth ulcers or thrush) or oral wounds, such as those following oral surgery or dental extraction.

6.1       Clinical Trials Experience

      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 clinical practice.

      Adults

      The safety data described below are based on 6 clinical trials which randomized 3589 subjects 18 through 65 years of age with Timothy grass pollen induced rhinitis with or without conjunctivitis, including 1669 subjects who were exposed to at least one dose of GRASTEK. Of the subjects treated with GRASTEK, 25% had mild asthma and 80% were sensitized to other allergens in addition to grass. The subject population was 88% White, 7% African American, and 3% Asian. Subjects were 52% male, and 88% of subjects were between 18 and 50 years of age. Subject demographics in placebo-treated subjects were similar to the active group.

      The most common adverse reactions reported in subjects treated with GRASTEK were oral pruritus (26.7% vs 3.5% placebo), throat irritation (22.6% vs 2.8%), ear pruritus (12.5% vs 1.1%) and mouth edema (11.1% vs 0.8%). The percentage of subjects who discontinued from the clinical trials because of an adverse reaction while exposed to GRASTEK or placebo was 4.9% and 0.9%, respectively. The most common adverse reactions that led to study discontinuation in subjects who were exposed to GRASTEK were pharyngeal edema and oral pruritus.

      Seven adult subjects (7/1669; 0.4%) who received GRASTEK experienced treatment-related systemic allergic reactions that led to discontinuation of GRASTEK in four out of the seven subjects.

• Five of the seven subjects had reactions on Day 1 of treatment with GRASTEK. Symptoms included swelling of lips/mouth; oral/pharyngeal itching; ear itching, sneezing, rhinorrhea, throat irritation, dysphonia, dysphagia, chest discomfort, and rash. Three of the five subjects received treatment with epinephrine and antihistamines, and one of the three also received oral corticosteroids. One of the five subjects who had a reaction on Day 1 of treatment with GRASTEK also had a reaction on Day 2 of treatment with GRASTEK. Symptoms on Day 2 included oral burning sensation; rhinorrhea; and throat irritation.
  
• One of the seven subjects had a reaction on Day 2 after tolerating treatment with GRASTEK on Day 1. Symptoms included edema of the lower lip, epigastric discomfort and dizziness.
  
• One of the seven subjects developed chest tightness and shortness of breath on Day 42 of treatment with GRASTEK.

      Adverse reactions reported in ≥1% of subjects treated with GRASTEK are shown in Table 1.

      Table 1: Adverse Reactions Reported in ≥1% of Adults Treated with GRASTEK

      Adverse reactions of interest that occurred in ≤1% of GRASTEK recipients include abdominal pain and gastroesophageal reflux.

      Pediatrics

      Safety data are based on 3 clinical trials which randomized 881 subjects between 5 and 17 years of age with grass pollen induced rhinitis with or without conjunctivitis. Overall, 445 subjects received at least one dose of GRASTEK. Of the subjects treated with GRASTEK, 31% had mild asthma and 86% were sensitized to other allergens in addition to grass. The subject population was 86% White, 7% African American and 3% multi-racial. The majority (66%) of subjects were male. The mean age of subjects was 11.7 years. Subject demographics in placebo-treated subjects were similar to the active group.

      The most common adverse reactions in pediatric subjects treated with GRASTEK were oral pruritus (24.4% vs 2.1% placebo), throat irritation (21.3% vs 2.5%) and mouth edema (9.8% vs 0.2%). The percentage of subjects who discontinued from the clinical trials because of an adverse reaction while exposed to GRASTEK or placebo was 6.3% and 0.7%, respectively.

      One pediatric subject (1/447; 0.2%) who received GRASTEK experienced a treatment-related systemic allergic reaction consisting of lip angioedema, slight dysphagia due to the sensation of a lump in the throat, and intermittent cough which was of moderate intensity on Day 1. The subject was treated with epinephrine, recovered, and was discontinued from the trial.

      Adverse reactions reported in ≥1% of subjects treated with GRASTEK are shown in Table 2.

      Table 2: Adverse Reactions Reported in ≥1% of Pediatric Subjects Treated with GRASTEK

6.2       Postmarketing Experience

      Postmarketing Safety Studies

      In European post-approval studies which included 1,666 patients treated with GRASTEK (marketed under the name GRAZAX), reported serious adverse reactions assessed as related to GRASTEK use included anaphylactic reaction, asthma exacerbation, hoarseness, laryngitis, oral ulceration, and ulcerative colitis exacerbation.

      Spontaneous Postmarketing Reports

      The following adverse reactions have been identified during post-approval use of GRASTEK (marketed under the name GRAZAX in Europe). Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. These include: altered state of consciousness, anaphylactic shock, angioedema, asthma exercise induced, chest pressure, diarrhea, difficulty speaking, dizziness, drowsiness, enlarged uvula, eosinophilic esophagitis, erythema facial, face edema, forced expiratory volume decreased, heart rate increased, heart rate irregular, hyperventilation, hypotension, laryngeal discomfort, oral pain, oxygen saturation decreased, peak expiratory flow rate decreased, pneumonia, rash, respiratory distress, sensation of foreign body, status asthmaticus, stridor, swelling of neck, throat pruritus, tremor, vital capacity decreased, vomiting, and wheezing. Included in these reports was an adult male with asthma who experienced anaphylactic shock within two minutes of administration of GRASTEK. The patient experienced depressed level of consciousness, hypotension, increased heart rate, wheezing, urticaria, and face edema.

      Eosinophilic esophagitis has been reported following treatment with GRASTEK (marketed under the name GRAZAX). The clinical details of some postmarketing reports are consistent with a drug-induced effect, including at least one case with resolution of symptoms upon discontinuation of GRASTEK, relapse after resuming GRASTEK and resolution again after discontinuation of GRASTEK.

8.1       Pregnancy

      Risk Summary

      All pregnancies have a risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Available human data do not establish the presence or absence of GRASTEK-associated risks during pregnancy. 

      In two reproductive and developmental toxicity studies mice were administered Timothy grass pollen extract daily by buccal cavity at doses approximately 6.7 times the human sublingual dose. In one study doses were administered during gestation and lactation. In the other study doses were administered prior to mating and during gestation. These studies revealed no evidence of harm to the mother or the fetus due to GRASTEK (see 8.1 Data).

      Data

      Animal Data 

      A pre- and postnatal developmental study and a combined fertility/developmental toxicity study were conducted in mice. In these studies, the effect of Timothy grass (Phleum pratense) pollen allergen extract, the active component of GRASTEK, on embryo-fetal development was evaluated. In the pre- and postnatal developmental toxicity study female mice were administered Timothy grass pollen allergen extract by buccal cavity daily from day 6 of gestation to day 17 of lactation at doses approximately 6.7 times the human sublingual dose. In the combined fertility/developmental toxicity study, female mice were administered Timothy grass pollen allergen extract daily by buccal cavity administration from 14 days prior to mating and until day 15 of the gestation period (male animals were administered the same dose daily for 4 weeks before pairing and during pairing) at doses approximately 6.7 times the human sublingual dose. Fertility was normal and there were no treatment-related post-implementation losses, fetal malformations or variations.

8.2       Lactation

      Risk Summary

      It is not known if GRASTEK is excreted in human milk. Data are not available to assess the effect of GRASTEK on milk production or on the breast-fed child. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for GRASTEK and any potential adverse effects on the breast-fed child from GRASTEK or from the underlying maternal condition. 

8.4       Pediatric Use

      Efficacy and safety of GRASTEK have been established in children and adolescents 5 through 17 years of age. The safety and efficacy in pediatric patients below 5 years of age have not been established.

8.5       Geriatric Use

      There is no clinical trial experience with GRASTEK in patients over 65 years of age.

12.1       Mechanism of Action

      The precise mechanisms of action of allergen immunotherapy are not known.

13.1       Carcinogenesis, Mutagenesis, Impairment of Fertility

      No studies have been performed in animals to evaluate the carcinogenic potential of GRASTEK.

      There were no positive findings in the in vitro mouse lymphoma and the bacterial reverse mutation assays for mutagenicity using Timothy grass (Phleum pratense) pollen allergen extract.

      A combined fertility/developmental  toxicity study in male and female mice revealed no evidence of impaired fertility due to Timothy grass pollen allergen extract administered daily prior to mating and during gestation at approximately 6.7 times the human sublingual dose (see 8.1 Data).

14.1       First Season Efficacy

      Adults and Children

      This placebo-controlled trial evaluated 1501 subjects 5 through 65 years of age (approximately 80% were 18 years and older) comparing GRASTEK (N=752) and placebo (N=749) administered as a sublingual tablet daily for approximately 24 weeks. The subject population was 84% White, 9% African American and 4% Asian. The majority of subjects were male (52%). In this study, approximately 25% of subjects had mild, intermittent asthma and 85% of all subjects were sensitized to other allergens in addition to grass pollen. Subjects with a clinical history of symptomatic allergies to non-grass pollen allergens that required treatment during the grass pollen season were excluded from the studies. All treatment groups were balanced with regard to baseline characteristics.

      Subjects treated with GRASTEK had a decrease in the TCS throughout the grass pollen season compared to placebo-treated subjects. Similarly, the DSS and DMS were decreased in subjects treated with GRASTEK compared to placebo throughout the grass pollen season, and the TCS was decreased compared to placebo during the peak grass pollen season (see Table 3).

      Table 3: Total Combined Scores (TCS), Rhinoconjunctivitis Daily Symptom Scores (DSS), and Daily Medication Scores (DMS) During the Grass Pollen Season

TCS=Total Combined Score (DSS + DMS); DSS=Daily Symptom Score; DMS=Daily Medication Score.

*       Non-parametric analysis for TCS and DSS endpoints: Parametric analysis using zero-inflated log-normal model for DMS.

†       Number of subjects in analyses.

‡       For TCS and DSS endpoints the group medians are reported, treatment difference and that relative to placebo is based on group medians. For DMS, the group means are reported and difference relative to placebo is based on estimated group means.

§       Difference relative to placebo computed as: (GRASTEK - placebo)/placebo x 100.

      Children

      This double-blind clinical trial of approximately 24 weeks duration evaluated 344 pediatric subjects 5 to 17 years of age who were treated with either GRASTEK or placebo once daily. The subject population was 88% White, 7% African American, and 2% Asian. The majority (65%) of subjects were male. The mean age of subjects was 12.3 years. In this study, 26% of subjects had mild intermittent asthma and most subjects (89%) were sensitized to other allergens in addition to grass pollen. Subjects with a clinical history of symptomatic allergies to non-grass pollen allergens that required treatment during the grass pollen season were excluded from the studies. All treatment groups were balanced with regard to baseline characteristics.

      Pediatric subjects treated with GRASTEK had a decrease in TCS throughout the grass pollen season compared to placebo treated subjects (see Table 4). Similarly, the DSS and DMS were decreased in GRASTEK compared to placebo throughout the grass pollen season.

      Table 4: Total Combined Scores (TCS), Rhinoconjunctivitis Daily Symptom Scores (DSS) and Daily Medication Scores (DMS) During the Entire Grass Pollen Season

TCS=Total combined score (DSS + DMS); DSS=Daily Symptom Score; DMS=Daily Medication Score.

*       Parametric analysis using analysis of variance model for all endpoints.

†       Number of subjects in analyses.

‡       The estimated group means are reported and difference relative to placebo is based on estimated group means.

§       Difference relative to placebo computed as: (GRASTEK - placebo)/placebo x 100.

14.2       Sustained Effect

      Adult Subjects 18 Years and Older

      The sustained effect of GRASTEK was measured in a 5-year double-blind study. The study included 634 randomized subjects between 18 and 65 years of age. The subject population was 96% White, 2% Asian and 1% African American. The majority (59%) of subjects were male. The mean age of subjects was 34 years. Subjects received either GRASTEK or placebo daily for 3 consecutive years and were then observed for 2 subsequent years during which they did not receive study drug. Subjects treated with GRASTEK had a decrease in TCS throughout the grass pollen season during the three years of active treatment. This effect was sustained during the grass pollen season in the first year after discontinuation of GRASTEK (see Table 5), but not in the second year.

      Table 5: Rhinoconjunctivitis Total Combined Score (TCS), Daily Symptom Score (DSS), and Daily Medication Score (DMS) During the Entire Grass Pollen Season from the 5-Year Study

TCS=Total Combined Score (DSS + DMS); DSS=Daily Symptom Score; DMS=Daily Medication Score.

*       Difference relative to placebo computed as: (GRASTEK - placebo)/placebo x 100.

†       Number of subjects in analyses. 

‡       Study extended from 1 to 5 years (site closures, subject unwillingness to participate beyond 1 year).