5.1     Ototoxicity

Caution should be exercised when prescribing TOBI Podhaler to patients with known or suspected auditory or vestibular dysfunction.

Ototoxicity, as measured by complaints of hearing loss or tinnitus, was reported by patients in the TOBI Podhaler clinical studies [see Adverse Reactions (6.1)]. Tinnitus may be a sentinel symptom of ototoxicity, and therefore the onset of this symptom warrants caution. Ototoxicity, manifested as both auditory (hearing loss) and vestibular toxicity, has been reported with parenteral aminoglycosides. Vestibular toxicity may be manifested by vertigo, ataxia or dizziness.

5.2     Nephrotoxicity

Caution should be exercised when prescribing TOBI Podhaler to patients with known or suspected renal dysfunction.

Nephrotoxicity was not observed during TOBI Podhaler clinical studies but has been associated with aminoglycosides as a class.

5.3     Neuromuscular Disorders

Caution should be exercised when prescribing TOBI Podhaler to patients with known or suspected neuromuscular dysfunction.

TOBI Podhaler should be used cautiously in patients with neuromuscular disorders, such as myasthenia gravis or Parkinson’s disease, since aminoglycosides may aggravate muscle weakness because of a potential curare-like effect on neuromuscular function.

5.4     Bronchospasm

Bronchospasm has been reported with inhalation of TOBI Podhaler [see Adverse Reactions (6.1)]. Bronchospasm should be treated as medically appropriate.

5.5     Laboratory Tests

Audiograms

Physicians should consider an audiogram at baseline, particularly for patients at increased risk of auditory dysfunction.

If a patient reports tinnitus or hearing loss during TOBI Podhaler therapy, the physician should refer that patient for audiological assessment.

Serum Concentrations

In patients treated with TOBI Podhaler, serum tobramycin concentrations are approximately 1 to 2 mcg/mL one hour after dose administration and do not require routine monitoring. Serum concentrations of tobramycin in patients with known or suspected auditory or renal dysfunction or patients treated with a concomitant parenteral aminoglycoside (or other nephrotoxic or ototoxic medications) should be monitored at the discretion of the treating physician. If ototoxicity or nephrotoxicity occurs in a patient receiving TOBI Podhaler, tobramycin therapy should be discontinued until serum concentrations fall below 2 mcg/mL.

The serum concentration of tobramycin should only be monitored through venipuncture and not finger prick blood sampling. Contamination of the skin of the fingers with tobramycin may lead to falsely increased measurements of serum levels of the drug. This contamination cannot be completely avoided by hand washing before testing.

Renal Function

Laboratory tests of urine and renal function should be conducted at the discretion of the treating physician.

5.6     Use in Pregnancy

Aminoglycosides can cause fetal harm when administered to a pregnant woman. Aminoglycosides cross the placenta, and streptomycin has been associated with several reports of total, irreversible, bilateral congenital deafness in pediatric patients exposed in utero. Patients who use TOBI Podhaler during pregnancy, or become pregnant while taking TOBI Podhaler should be apprised of the potential hazard to the fetus [see Use in Specific Populations (8.1)].

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 practice.

TOBI Podhaler has been eva luated for safety in 425 cystic fibrosis patients exposed to at least one dose of TOBI Podhaler, including 273 patients who were exposed across three cycles (6 months) of treatment. Each cycle consisted of 28 days on-treatment (with 112 mg administered twice-daily) and 28 days off-treatment. Patients with serum creatinine ≥2 mg/dL and blood urea nitrogen (BUN) ≥40 mg/dL were excluded from clinical studies. There were 218 males and 207 females in this population, and reflecting the cystic fibrosis population in the U.S., the vast majority of patients were Caucasian. There were 221 patients ≥20 years old, 121 patients ≥13 to <20 years old, and 83 patients ≥6 to <13 years old. There were 239 patients with screening FEV1 % predicted ≥50%, 156 patients with screening FEV1 % predicted <50%, and 30 patients with missing FEV1 % predicted.

The primary safety population reflects patients from Study 1, an open-label study comparing TOBI Podhaler with TOBI (tobramycin inhalation solution, USP) over three cycles of 4 weeks on treatment followed by 4 weeks off treatment. Randomization, in a planned 3:2 ratio, resulted in 308 patients treated with TOBI Podhaler and 209 patients treated with TOBI. For both the TOBI Podhaler and TOBI groups, mean exposure to medication for each cycle was 28 to 29 days. The mean age for both arms was between 25 and 26 years old. The mean baseline FEV1 % predicted for both arms was 53%.

Table 1 displays adverse drug reactions reported by at least 2% of TOBI Podhaler patients in Study 1, inclusive of all cycles (on and off treatment). Adverse drug reactions are listed according to MedDRA system organ class and sorted within system organ class group in descending order of frequency.

Adverse drug reactions that occurred in <2% of patients treated with TOBI Podhaler in Study 1 were: bronchospasm (TOBI Podhaler 1.6%, TOBI 0.5%); deafness including deafness unilateral (reported as mild to moderate hearing loss or increased hearing loss) (TOBI Podhaler 1.0%, TOBI 0.5%); and tinnitus (TOBI Podhaler 1.9%, TOBI 2.4%).

Discontinuations in Study 1 were higher in the TOBI Podhaler arm compared to TOBI (27% TOBI Podhaler versus 18% TOBI). This was driven primarily by discontinuations due to adverse events (14% TOBI Podhaler versus 8% TOBI). Higher rates of discontinuation were seen in subjects ≥20 years old and those with baseline FEV1 % predicted <50%.

Respiratory related hospitalizations occurred in 24% of the patients in the TOBI Podhaler arm and 22% of the patients in the TOBI arm. There was an increased new usage of antipseudomonal medication in the TOBI Podhaler arm (65% TOBI Podhaler versus 55% TOBI). This included oral antibiotics in 55% of TOBI Podhaler patients and 40% of TOBI patients and intravenous antibiotics in 35% of TOBI Podhaler patients and 33% of TOBI patients. Median time to first antipseudomonal usage was 89 days in the TOBI Podhaler arm and 112 days in the TOBI arm.

The supportive safety population reflects patients from two studies: Study 2, a double-blind, placebo-controlled design for the first treatment cycle, followed by all patients receiving TOBI Podhaler (replaced placebo) for two additional cycles, and Study 3, a double-blind, placebo-controlled trial for one treatment cycle only. Placebo in these studies was inhaled powder without the active ingredient, tobramycin. The patient population for these studies was much younger than in Study 1 (mean age 13 years old).

Adverse drug reactions reported more frequently by TOBI Podhaler patients in the placebo-controlled cycle (Cycle 1) of Study 2, which included 46 TOBI Podhaler and 49 placebo patients, were:

      Respiratory, thoracic, and mediastinal disorders

      Pharyngolaryngeal pain (TOBI Podhaler 10.9%, placebo 0%); dysphonia (TOBI Podhaler 4.3%, placebo 0%)

      Gastrointestinal disorders

      Dysgeusia (TOBI Podhaler 6.5%, placebo 2.0%)

Adverse drug reactions reported more frequently by TOBI Podhaler patients in Study 3, which included 30 TOBI Podhaler and 32 placebo patients, were:

      Respiratory, thoracic, and mediastinal disorders

      Cough (TOBI Podhaler 10%, placebo 0%)

      Ear and labyrinth disorders

      Hypoacusis (TOBI Podhaler 10%, placebo 6.3%)

Audiometric Assessment

In Study 1, audiology testing was performed in a subset of approximately 25% of TOBI Podhaler (n=78) and TOBI (n=45) patients. Using the criteria for either ear of ≥10 dB loss at two consecutive frequencies, ≥20 dB loss at any frequency, or loss of response at three consecutive frequencies where responses were previously obtained, five TOBI Podhaler patients and three TOBI patients were judged to have ototoxicity, a ratio similar to the planned 3:2 randomization for this study.

Audiology testing was also performed in a subset of patients in both Study 2 (n=13 from the TOBI Podhaler group and n=9 from the placebo group) and Study 3 (n=14 from the TOBI Podhaler group and n=11 from the placebo group). In Study 2, no patients reported hearing complaints but two TOBI Podhaler patients met the criteria for ototoxicity. In Study 3, three TOBI Podhaler and two placebo patients had reports of ‘hypoacusis.’ One TOBI Podhaler and two placebo patients met the criteria for ototoxicity. In some patients, ototoxicity was transient or may have been related to a conductive defect.

Cough

Cough is a common symptom in cystic fibrosis, reported in 42% of the patients in Study 1 at baseline. Cough was the most frequently reported adverse event in Study 1 and was more common in the TOBI Podhaler arm (48% TOBI Podhaler versus 31 % TOBI). There was a higher rate of cough adverse event reporting during the first week of active treatment with TOBI Podhaler (i.e., the first week of Cycle 1). The time to first cough event in the TOBI Podhaler and TOBI groups were similar thereafter. In some patients, cough resulted in discontinuation of TOBI Podhaler treatment. Sixteen patients (5%) receiving treatment with TOBI Podhaler discontinued study treatment due to cough events compared with 2 (1%) in the TOBI treatment group. Children and adolescents coughed more than adults when treated with TOBI Podhaler, yet the adults were more likely to discontinue: of the 16 patients on TOBI Podhaler in Study 1 who discontinued treatment due to cough events, 14 were ≥20 years of age, one patient was between the ages of 13 and <20, and one was between the ages of 6 and <13. The rates of bronchospasm (as measured by ≥20% decrease in FEV1 % predicted post-dose) were approximately 5% in both treatment groups, and none of these patients experienced concomitant cough.

In Study 2, cough was the most commonly reported adverse event during the first cycle of treatment (the double blind period of treatment) and occurred more frequently in placebo-treated patients (26.5%) than patients treated with TOBI Podhaler (13%). Similar percentages of patients in both treatment groups reported cough as a baseline symptom. In Study 3, cough events were reported by three patients in the TOBI Podhaler group (10%) and none in the placebo group (0%).

6.2     Postmarketing Experience

The following adverse reactions have been identified during postapproval use of TOBI Podhaler. 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.

Respiratory, thoracic, and mediastinal disorders

Aphonia, Sputum discolored

General disorders and administration site conditions

Malaise

8.1     Pregnancy

Teratogenic Effects – Pregnancy Category D [see Warnings and Precautions (5.6)]

No reproduction toxicology studies have been conducted with TOBI Podhaler. However, subcutaneous administration of tobramycin at doses of 100 or 20 mg/kg/day during organogenesis was not teratogenic in rats or rabbits, respectively. Doses of tobramycin ≥40 mg/kg/day were severely maternally toxic to rabbits and precluded the eva luation of teratogenicity. Ototoxicity was not eva luated in offspring during nonclinical reproduction toxicity studies with tobramycin.

Aminoglycosides can cause fetal harm (e.g., congenital deafness) when administered to a pregnant woman. No adequate and well-controlled studies of TOBI Podhaler in pregnant women have been conducted. If TOBI Podhaler is used during pregnancy, or if the patient becomes pregnant while taking TOBI Podhaler, the patient should be apprised of the potential hazard to the fetus.

8.3     Nursing Mothers

The amount of tobramycin excreted in human breast milk after administration by inhalation is not known. Because of the potential for ototoxicity and nephrotoxicity in infants, a decision should be made whether to terminate nursing or discontinue the drug, taking into account the importance of the drug to the mother.

8.4     Pediatric Use

Patients 6 years and older were included in the Phase 3 studies with TOBI Podhaler; 206 patients below 20 years of age received TOBI Podhaler. No dosage adjustments are needed based on age. The overall pattern of adverse events in pediatric patients was similar to the adults. Dysgeusia (taste disturbance) was more commonly reported in younger patients six to 19 years of age than in patients 20 years and older, 7.4% versus 2.7%, respectively. Safety and effectiveness in pediatric patients below the age of 6 years have not been established.

8.5     Geriatric Use

Clinical studies of TOBI Podhaler did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from younger subjects. Tobramycin is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, it may be useful to monitor renal function [see Warnings and Precautions (5.2, 5.5)].

8.6     Renal Impairment

Tobramycin is primarily excreted unchanged in the urine and renal function is expected to affect the exposure to tobramycin. The risk of adverse reactions to this drug may be greater in patients with impaired renal function. Patients with serum creatinine ≥2 mg/dL and blood urea nitrogen (BUN) ≥40 mg/dL have not been included in clinical studies and there are no data in this population to support a recommendation regarding dose adjustment with TOBI Podhaler [see Warnings and Precautions (5.2, 5.5)].

8.7     Hepatic Impairment

No studies have been performed in patients with hepatic impairment. As tobramycin is not metabolized, an effect of hepatic impairment on the exposure to tobramycin is not expected.

8.8     Organ Transplantation

Adequate data do not exist for the use of TOBI Podhaler in patients after organ transplantation.