CAYSTON

A dose of CAYSTON consists of a 2 mL amber glass vial containing lyophilized aztreonam (75 mg) and lysine (46.7 mg), and a low-density polyethylene ampule containing 1 mL sterile diluent (0.17% sodium chloride). The reconstituted solution is for inhalation. The formulation contains no preservatives or arginine. The active ingredient in CAYSTON is aztreonam, a monobactam antibacterial. The monobactams are structurally different from beta-lactam antibiotics (e.g., penicillins, cephalosporins, carbapenems) due to a monocyclic nucleus. This nucleus contains several side chains; sulfonic acid in the 1-position activates the nucleus, an aminothiazolyl oxime side chain in the 3-position confers specificity for aerobic Gram-negative bacteria including Pseudomonas spp ., and a methyl group in the 4-position enhances beta-lactamase stability. Aztreonam is designated chemically as ( Z )-2-[[[(2-amino-4-thiazolyl)[[(2 S ,3 S )-2-methyl-4-oxo-1-sulfo-3-azetidinyl]carbamoyl]methylene]amino]oxy]-2-methylpropionic acid. The structural formula is presented below: CAYSTON is a white to off-white powder. CAYSTON is sterile, hygroscopic, and light sensitive. Once reconstituted with the supplied diluent, the pH range is 4.5 to 6.0. Chemical Structure

CAYSTON ® is indicated to improve respiratory symptoms in cystic fibrosis (CF) patients with Pseudomonas aeruginosa . Safety and effectiveness have not been established in pediatric patients below the age of 7 years, patients with FEV 1 <25% or >75% predicted, or patients colonized with Burkholderia cepacia [see Clinical Studies (14) ]. To reduce the development of drug-resistant bacteria and maintain the effectiveness of CAYSTON and other antibacterial drugs, CAYSTON should be used only to treat patients with CF known to have Pseudomonas aeruginosa in the lungs. CAYSTON is a monobactam antibacterial indicated to improve respiratory symptoms in cystic fibrosis (CF) patients with Pseudomonas aeruginosa . Safety and effectiveness have not been established in pediatric patients below the age of 7 years, patients with FEV 1 <25% or >75% predicted, or patients colonized with Burkholderia cepacia . ( 1 )

Administer one dose (one single use vial and one ampule of diluent) 3 times a day for 28 days. ( 2.1 ) Use dose immediately after reconstitution. ( 2.2 ) Administer only with the Altera ® Nebulizer System. Do not administer with any other type of nebulizer. ( 2.3 ) 2.1 Dosing Information The recommended dose of CAYSTON for both adults and pediatric patients 7 years of age and older is one single-use vial (75 mg of aztreonam) reconstituted with 1 mL of sterile diluent administered 3 times a day for a 28-day course (followed by 28 days off CAYSTON therapy). Dosage is not based on weight or adjusted for age. Doses should be taken at least 4 hours apart. CAYSTON is administered by inhalation using an Altera ® Nebulizer System. Patients should use a bronchodilator before administration of CAYSTON. 2.2 Instructions for CAYSTON Reconstitution CAYSTON should be administered immediately after reconstitution. Do not reconstitute CAYSTON until ready to administer a dose. Take one amber glass vial containing CAYSTON and one diluent ampule from the carton. To open the glass vial, carefully remove the blue cap and metal ring and remove the gray rubber stopper. Twist the tip off the diluent ampule and squeeze the liquid into the glass vial. Replace the rubber stopper, then gently swirl the vial until contents have completely dissolved. The empty vial, stopper, and diluent ampule should be disposed of properly upon completion of dosing. 2.3 Instructions for CAYSTON Administration CAYSTON is administered by inhalation using an Altera Nebulizer System. CAYSTON should not be administered with any other nebulizer. CAYSTON should not be mixed with any other drugs in the Altera Nebulizer Handset. CAYSTON is not for intravenous or intramuscular administration. Patients should use a bronchodilator before administration of CAYSTON. Short-acting bronchodilators can be taken between 15 minutes and 4 hours prior to each dose of CAYSTON. Alternatively, long-acting bronchodilators can be taken between 30 minutes and 12 hours prior to administration of CAYSTON. For patients taking multiple inhaled therapies, the recommended order of administration is as follows: bronchodilator, mucolytics, and lastly, CAYSTON. To administer CAYSTON, pour the reconstituted solution into the handset of the nebulizer system. Turn the unit on. Place the mouthpiece of the handset in your mouth and breathe normally only through your mouth. Administration typically takes between 2 and 3 minutes. Further patient instructions on how to administer CAYSTON are provided in the FDA-approved patient labeling. Instructions on testing nebulizer functionality and cleaning the handset are provided in the Instructions for Use included with the nebulizer system.

CAYSTON is contraindicated in patients with a known allergy to aztreonam. Contraindicated in patients with a known allergy to aztreonam. ( 4 )

Common adverse reactions (more than 5%) occurring more frequently in CAYSTON patients are cough, nasal congestion, wheezing, pharyngolaryngeal pain, pyrexia, chest discomfort, abdominal pain and vomiting. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Gilead Sciences, Inc. at 1-800-GILEAD5, option 3 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of drugs cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of CAYSTON was evaluated in 344 patients from two placebo-controlled trials and one open-label follow-on trial. In controlled trials, 146 patients with CF received 75 mg CAYSTON 3 times a day for 28 days. Table 1 displays adverse reactions reported in more than 5% of patients treated with CAYSTON 3 times a day in placebo-controlled trials. The listed adverse reactions occurred more frequently in CAYSTON-treated patients than in placebo-treated patients. Table 1 Adverse Reactions Reported in more than 5% of Patients Treated with CAYSTON in the Placebo-Controlled Trials Event (Preferred Term) Placebo (N=160) n (%) CAYSTON 75 mg 3 times a day (N=146) n (%) Cough 82 (51%) 79 (54%) Nasal congestion 19 (12%) 23 (16%) Wheezing 16 (10%) 23 (16%) Pharyngolaryngeal pain 17 (11%) 18 (12%) Pyrexia 9 (6%) 19 (13%) Chest discomfort 10 (6%) 11 (8%) Abdominal Pain 8 (5%) 10 (7%) Vomiting 7 (4%) 9 (6%) Adverse reactions that occurred in less than 5% of patients treated with CAYSTON were bronchospasm (3%) [see Warnings and Precautions (5.2) ] and rash (2%). 6.2 Postmarketing Experience In addition to adverse reactions reported from clinical trials, the following possible adverse reactions have been identified during post-approval use of CAYSTON. Because these events have been reported voluntarily from a population of unknown size, estimates of frequency cannot be made. MUSCULOSKELETAL AND CONNECTIVE TISSUE DISORDERS Arthralgia, joint swelling

No formal clinical studies of drug interactions with CAYSTON have been conducted.

CAYSTON vials and diluent ampules should be stored in the refrigerator at 2 °C to 8 °C (36 °F to 46 °F) until needed. Once removed from the refrigerator, CAYSTON and diluent may be stored at room temperature (up to 25 °C/77 °F) for up to 28 days. Do not separate the CAYSTON vials from the diluent ampules. CAYSTON should be protected from light. Do not use CAYSTON if it has been stored at room temperature for more than 28 days. Do not use CAYSTON beyond the expiration date stamped on the vial. Do not use diluent beyond the expiration date embossed on the ampule. CAYSTON should be used immediately upon reconstitution. Do not reconstitute more than one dose at a time. Do not use diluent or reconstituted CAYSTON if it is cloudy or if there are particles in the solution.