Kew KM, Dias S, Cates CJ Long-acting inhaled therapy (beta-agonists, anticholinergics and steroids) for COPD: a network meta-analysis. Cochrane Database Syst Rev. 2014 Mar 26;3:CD010844. doi: 10.1002/14651858.CD010844.pub2. Review.
Kew KM, Mavergames C, Walters JA Long-acting beta2-agonists for chronic obstructive pulmonary disease. Cochrane Database Syst Rev. 2013 Oct 15;10:CD010177. doi: 10.1002/14651858.CD010177.pub2. Review.
Khoukaz G, Gross NJ Effects of salmeterol on arterial blood gases in patients with stable chronic obstructive pulmonary disease. Comparison with albuterol and ipratropium. Am J Respir Crit Care Med. 1999 Sep;160(3):1028-30.
Pillet O, Manier G, Castaing Y Anticholinergic versus beta 2-agonist on gas exchange in COPD: a comparative study in 15 patients. Monaldi Arch Chest Dis. 1998 Feb;53(1):3-8.
Roskell NS, Anzueto A, Hamilton A, Disse B, Becker K Once-daily long-acting beta-agonists for chronic obstructive pulmonary disease: an indirect comparison of olodaterol and indacaterol. Int J Chron Obstruct Pulmon Dis. 2014 Jul 31;9:813-24. doi: 10.2147/COPD.S59673. eCollection 2014. Review.
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
