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.

5.1 Allergic Reactions

Severe allergic reactions have been reported following administration of aztreonam for injection to patients with no known history of exposure to aztreonam. In addition, allergic reaction with facial rash, facial swelling, and throat tightness was reported with CAYSTON in clinical trials. If an allergic reaction to CAYSTON occurs, stop administration of CAYSTON and initiate treatment as appropriate.

Caution is advised when administering CAYSTON to patients if they have a history of beta-lactam allergy, although patients with a known beta-lactam allergy have received CAYSTON in clinical trials and no severe allergic reactions were reported. A history of allergy to beta-lactam antibiotics, such as penicillins, cephalosporins, and/or carbapenems, may be a risk factor, since cross-reactivity may occur.

5.2 Bronchospasm

Bronchospasm is a complication associated with nebulized therapies, including CAYSTON. Reduction of 15% or more in forced expiratory volume in 1 second (FEV1) immediately following administration of study medication after pretreatment with a bronchodilator was observed in 3% of patients treated with CAYSTON.

5.3 Decreases in FEV1 After 28-Day Treatment Cycle

In clinical trials, patients with increases in FEV1 during a 28-day course of CAYSTON were sometimes treated for pulmonary exacerbations when FEV1 declined after the treatment period. Healthcare providers should consider a patient's baseline FEV1 measured prior to CAYSTON therapy and the presence of other symptoms when evaluating whether post-treatment changes in FEV1 are caused by a pulmonary exacerbation.

5.4 Development of Drug-Resistant Bacteria

Prescribing CAYSTON in the absence of known Pseudomonas aeruginosa infection in patients with CF is unlikely to provide benefit and increases the risk of development of drug-resistant bacteria.

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.

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

8.1 Pregnancy

8.2 Lactation

8.4 Pediatric Use

Patients 7 years and older were included in clinical trials with CAYSTON. Fifty-five patients under 18 years of age received CAYSTON in placebo-controlled trials. No dose adjustments were made for pediatric patients. Pyrexia was more commonly reported in pediatric patients than in adult patients. Safety and effectiveness in pediatric patients below the age of 7 years have not been established.

8.5 Geriatric Use

Clinical trials of CAYSTON did not include CAYSTON-treated patients aged 65 years of age and older to determine whether they respond differently from younger patients.

8.6 Use in Patients with Renal Impairment

Aztreonam is known to be excreted by the kidney. Placebo-controlled clinical trials with CAYSTON excluded patients with abnormal baseline renal function (defined as serum creatinine greater than 2 times the upper limit of normal range). Given the low systemic exposure of aztreonam following administration of CAYSTON, clinically relevant accumulation of aztreonam is unlikely to occur in patients with renal impairment. Therefore, CAYSTON may be administered to patients with mild, moderate and severe renal impairment with no dosage adjustment.

12.1 Mechanism of Action

Aztreonam is an antibacterial drug [see Clinical Pharmacology (12.4)].

12.3 Pharmacokinetics

12.4 Microbiology

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

A 104-week rat inhalation toxicology study to assess the carcinogenic potential of aztreonam demonstrated no drug-related increase in the incidence of tumors. Rats were exposed to aerosolized aztreonam for up to 4 hours per day. Peak plasma levels of aztreonam averaging approximately 6.8 mcg/mL were measured in rats at the highest dose level. This is approximately 12-fold higher than the average peak plasma level measured in humans following CAYSTON therapy.

Genetic toxicology studies performed in vitro demonstrated that aztreonam did not induce structural chromosome aberrations in CHO cells and did not induce mutations at the TK locus in mouse lymphoma L5178Y TK+/- cells. In vivo, aztreonam was not clastogenic in mouse bone marrow cells.

Aztreonam did not impair the fertility of rats when administered parenterally at doses up to 2400 mg/kg/day that would provide systemic exposures significantly higher than peak plasma levels measured in humans following CAYSTON therapy.

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.

Allergic Reactions

Advise patients to tell their healthcare provider immediately if they believe they are experiencing new or worsening symptoms or believe they are having an allergic reaction to CAYSTON [see Warnings and Precautions (5.1)].

Development of Drug-Resistant Bacteria

Counsel patients that antibacterial drugs including CAYSTON should only be used to treat bacterial infections. They do not treat viral infection (e.g., the common cold). When CAYSTON is prescribed to treat a bacterial infection, inform patients that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by CAYSTON or other antibacterial drugs in the future [see Warnings and Precautions (5.4)].

Reconstitution and Administration

Advise patients that:

• CAYSTON is for inhalation use only and should only be administered using the Altera Nebulizer System.
• CAYSTON should only be reconstituted with the provided diluent. Instruct patients not to mix other drugs with CAYSTON in the Altera Nebulizer System.

Advise patients to:

• use a bronchodilator prior to administration of CAYSTON.
• complete the full 28-day course of CAYSTON even if they are feeling better.

Advise patients taking several inhaled medications to use the medications in the following order: bronchodilator, mucolytics, and lastly, CAYSTON.

Missed Dose

Inform the patient that if they miss a dose, they should take all 3 daily doses as long as the doses are at least 4 hours apart.