The Effect of STIOLTO™ RESPIMAT® on Fatigue in Chronic Obstructive Pulmonary Disease

Patients with chronic obstructive pulmonary disease (COPD) have reduced exercise tolerance. One mechanism for this is thought to be due to dynamic hyperinflation during exercise (an increase in the end-expiratory lung volume) that contributes to the sensation of breathlessness. Whether this also contributes to inhibiting motor recruitment, and reduces the available power output (termed performance fatigue; PF), is not well understood. Preliminary data suggests that many COPD patients, unlike healthy subjects, stop exercise with a 'skeletal muscle power reserve' i.e. the ability to acutely increase muscle power output. This suggests that they are limited in the exercise task by mechanisms other than acute intramuscular limitations to power production (termed muscle fatigue; MF). Exercise tolerance is increased by treatment with the fixed-dose combination bronchodilator, STIOLTO™ RESPIMAT®. We hypothesize that increased exercise tolerance with STIOLTO™ RESPIMAT® (reduced performance fatigue; PF) will be mediated by a combination of: 1) reduced inhibition of muscle activation (termed activation fatigue; AF) allowing patients to drive their leg muscles harder, and thus; 2) increased muscle fatigue (MF).

Inclusion criteria

• All patients must have a diagnosis of chronic obstructive pulmonary disease and must meet the following criteria: (a) Patients must be in a stable state of their disease with no exacerbation within the previous 4 weeks; and (b) At visit 1 spirometric must demonstrate a post-bronchodilator FEV1 <80% of predicted normal and a post-bronchodilator FEV1/FVC <70%.
• At visit 1, patients will demonstrate appreciable reversibility, defined as a 12% increase in FEV1 in response to albuterol administration.
• Baseline dyspnea index focal score ≤ 9.
• Male or female patients, between 45 and 90 years (inclusive) of age.
• Patients must be current or ex-smokers with a smoking history of more than 10 pack-years
• Patients must be able to perform technically acceptable pulmonary function tests must be able to complete multiple symptom-limited cycle ergometry tests.
• Patients must be able to inhale medication in a competent manner from the inhalers used in the study.

Exclusion criteria

• Patients with a significant disease other than COPD; a significant disease is defined as a disease which, in the opinion of the investigator, may (i) put the patient at risk because of participation in the study, (ii) influence the results of the study, or (iii) cause concern regarding the patient's ability to participate in the study.
• Patients with a documented history of asthma. For patients with allergic rhinitis or atopy, medical records will be required to verify that the patient does not have asthma.
• Patients with any of the following conditions:

• A history of myocardial infarction within 1 year of screening visit.
• Unstable or life-threatening cardiac arrhythmia.
• Hospitalized for heart failure within the past year.
• Known active tuberculosis.
• A malignancy for which patient has undergone resection, radiation therapy or chemotherapy within last two years (patients with treated basal cell carcinoma are allowed).
• A history of life-threatening pulmonary obstruction within the past two years.
• A history of cystic fibrosis.
• Clinically evident bronchiectasis.
• A history of significant alcohol or drug abuse within the past two years.
• Any contraindications for exercise testing as outlined below (see contraindications to exercise).
• Patients who have undergone thoracotomy with pulmonary resection.
• Patients being treated with oral corticosteroid medication at unstable doses (i.e., less than six weeks on a stable dose) or at doses in excess of the equivalent of 10 mg of prednisone per day or 20 mg every other day.
• Patients who regularly use daytime oxygen therapy for more than one hour per day and in the investigator's opinion will be unable to abstain from the use of oxygen therapy during clinic visits.
• Patients who desaturate to SpO2 <85% on screening incremental exercise testing.
• Patients who have completed a pulmonary rehabilitation program in the six weeks prior to the screening visit or patients who are currently in a pulmonary rehabilitation program.
• Patients who have a limitation of exercise performance as a result of factors other than fatigue or exertional dyspnea, such as arthritis in the leg, angina pectoris or claudication or morbid obesity.
• Patients with a constant power cycle ergometry endurance time less than 4 or greater than 10 minutes after work rate adjustment procedures (described below).
• Patients who have taken an investigational drug within one month or six half-lives (whichever is greater) prior to screening visit (Visit 1).
• Pregnant or nursing women.
• Women of childbearing who have the potential not to be using a highly effective method of birth control. Female patients will be considered to be of childbearing potential unless surgically sterilized by hysterectomy or bilateral tubal ligation, or post-menopausal for at least two years.
• Patients who are currently participating in another interventional study.
• Patients who are unable to comply with pulmonary medication restrictions prior to randomization.