Randomized, Phase IIIb, Three-period, Three-treatment, Double-blind, Multi-center, Crossover Study to Evaluate the 24-hour Lung Function Profile in Subjects with Moderate to Very Severe COPD after 4 Weeks of Treatment with PT003, Open-Label Spiriva® Respimat® (Tiotropium Bromide) as an Active Control, and Placebo.

Inclusion Criteria:

• At least 40 years of age and no older than 80 at Screening
• Women of non-child bearing potential or negative serum pregnancy test at Screening, and agrees to acceptable contraceptive methods used consistently and correctly Screening until 14 days after final visit.
• Subjects with an established clinical history of COPD as defined by the American Thoracic Society (ATS)/European Respiratory Society (ERS)
• Current or former smokers with a history of at least 10 pack-years of cigarette smoking
• Pre- and post-bronchodilator FEV1/FVC ratio of <0.70
• Post-bronchodilator FEV1 must be <80% predicted normal value, calculated using NHANES III reference equations, and the measured FEV1 must also be ≥750 mL if FEV1 <30% of predicted normal value.

Exclusion Criteria:

• Significant diseases other than COPD, i.e., disease or condition which, in the opinion of the Investigator, may put the subject at risk because of participation in the study or may influence either the results of the study or the subject's ability to participate in the study.
• Women who are pregnant or lactating.
• Subjects, who in the opinion of the Investigator, have a current diagnosis of asthma.
• Subjects who have been hospitalized due to poorly controlled COPD within 3 months prior to Screening or during the Screening Period.
• Subjects who have poorly controlled COPD, defined as acute worsening of COPD that requires treatment with oral corticosteroids or antibiotics within 6 weeks prior to Screening or during the Screening Period.
• Subjects who have clinically significant uncontrolled hypertension.
• Subjects who have cancer that has not been in complete remission for at least five years.
• Subjects with abnormal liver function tests defined as AST, ALT, or total bilirubin ≥1.5 times upper limit of normal at Screening and on repeat testing.
• Subjects with a diagnosis of angle closure glaucoma will be excluded, regardless of whether or not they have been treated. Subjects with a diagnosis of open angle glaucoma who have intraocular pressure controlled with medication(s) are eligible.
• Subjects with symptomatic prostatic hypertrophy that is clinically significant in the opinion of the Investigator. Subjects with a trans-urethral resection of prostate (TURP) or full resection of the prostate within 6 months prior to Screening are excluded from the study.
• Subjects with bladder neck obstruction or urinary retention that is clinically significant in the opinion of the Investigator.