This study is designed to evaluate the effect of fluticasone furoate (FF, GW685698)/vilanterol (VI, GW642444) Inhalation Powder once daily (QD) on arterial stiffness compared with Tiotropium QD over 12 week treatment period in subjects with COPD and aortic pulse wave velocity (aPWV) > 12.0 m/s at Visit 1. Arterial stiffness will be measured as aPWV. This is a comparator, randomised, double-blind, double-dummy, parallel group, multi-centre study. Subjects who meet the eligibility criteria at Screening and meet the randomization criteria at the end of a 2-week Run-In period will enter a 12-week treatment period. There will be an approximate 7-day Follow-up period after the treatment period.

This is a Phase IIIb comparator, double-blind, double-dummy, randomised (1:1), parallel group, multi-centre study. At Visit 1 (Screening Visit), subjects who meet the pre-defined Inclusion Criteria and none of the Exclusion Criteria will enter a 2-week, single-blind placebo Run-in Period. The purpose of the Run-In Period is to monitor albuterol/salbutamol use at baseline, and to ensure that subjects' COPD is at a stable stage at randomization. Subject's adherence with study procedures, diary completion will also be evaluated during the Run-In Period. At the end of the Run-in period, subjects will be assessed and those who meet the randomisation criteria will receive one of the following two double-blind treatments for 12 weeks:

• FF (100 mcg)/VI (25 mcg) administered QD via a NDPI in the morning
• Tiotropium (18 mcg) administered QD via a HandiHaler in the morning

To ensure blinding of the treatments and to ensure a double-dummy design matching NDPI and HandiHaler will be utilised. Each subject will be instructed to self administer blinded study drug during the double blind treatment period as follows:

• Each morning take 1 inhalation from NDPI containing FF (100 mcg)/VI (25 mcg) followed by 1 inhalation from placebo capsule delivered via HandiHaler.
• Each morning take 1 inhalation from matching placebo NDPI followed by 1 inhalation from a capsule containing tiotropium 18 mcg delivered via HandiHaler.

An inhaled short acting beta2-receptor agonist, salbutamol/albuterol will be provided to subjects to use as needed throughout the Run-in and Treatment periods for relief of COPD symptoms. Ipratropium bromide is permitted if the subject is on a stable dose from Screening (Visit 1) and remains on the stable dose throughout the study. Subjects who experience an exacerbation of their COPD (which requires medication in addition to an increase in rescue medication) or a lower respiratory tract infection (LRTI) during the run-in period are not eligible to enter the treatment period. Any subject who experiences a similar COPD exacerbation (sec 4.4) or LRTI at any time on therapy will be withdrawn from the study. The aPWV will be measured at Screening and clinic Visits 3-5. Disease specific health status will be evaluated using the St. George's Respiratory Questionnaire (SGRQ-C), Euro Qol Questionnaire (EQ-5D) for COPD patients and the COPD Assessment Test (CAT) at Visit 2 (Day 1) and at Visit 5 (Weeks 12). The 12-lead ECG will be evaluated at Visit 1 (Screening) only. Vital signs (blood pressure and pulse rate), spirometry measurements, and clinical laboratory tests (hematology and chemistry) and other study-specific safety assessments will be obtained at selected clinic visits. A follow-up phone call will occur approximately 7 days after the last clinic visit. The overall study duration from Screening to Follow-up for each subject is approximately 15 weeks. Subjects will be considered to have completed the study upon completion of assessments and procedures up to and including completion of Follow-up Phone Contact (7 ± 2 days post Visit 5).

Inclusion Criteria:

• Type of subject: Outpatient
• Informed consent: Subjects must give their signed and dated written informed consent to participate.
• Gender: Male or female subjects.
• Age: greater then or equal to 40 years of age at Screening (Visit 1)
• COPD diagnosis: Subjects with a clinical history of COPD in accordance with the following definition by the American Thoracic Society (ATS) /European Respiratory Society(ERS).
• Subjects with a current or prior history ofgreater then or equal to 10 pack-years of cigarette smoking at Screening (Visit 1).
• Subjects with a measured post-albuterol/salbutamol FEV1 less then 70% of predicted at Screening (Visit 1).
• Subjects with a measured post-albuterol/salbutamol FEV1/FVC ratio of less then or equal to 0.70 at Screening (Visit 1).
• Exacerbation History: Subjects who have been hospitalised or have been treated with oral corticosteroids or antibiotics for their COPD within the last 3 years prior to Screening (V1).
• Baseline aPWV: subjects with a measured aPWV greater then 12.0 m/s at Screening (Visit 1).

Exclusion Criteria:

• Body Mass Index of less then or equal to 35

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.