Therapeutic targets of cystic fibrosis respiratory therapies. Physiological ramifications of reduced CFTR activity in the lungs of patients with cystic fibrosis are highlighted by large gray arrows. Therapeutic classes that have been and/or are being investigated for the chronic management of cystic fibrosis lung disease are shown in light gray boxes. Despite different mechanisms of action, all share the goal of reducing lung disease damage caused by the interplay of obstruction, infection, and inflammation. Reprinted with permission from VanDevanter DR, Konstan MW: Outcome measures for clinical trials assessing treatment of cystic fibrosis lung disease. Clinical Investigation 2012; 2(2):163-175 .