McDermott MM, et al. - The authors intended to analyze if granulocyte-macrophage colony-stimulating factor (GM-CSF) combined with supervised treadmill exercise led to an improvement in the 6-minute walk distance, compared with exercise alone and compared with GM-CSF alone. Additionally, they also contemplated if GM-CSF alone improved 6-minute walk more than placebo and whether exercise caused an improvement in the 6-minute walk more than an attention control intervention, in patients with peripheral artery disease (PAD). A substantial improvement was noted in the 6-minute walk distance due to supervised treadmill exercise than with attention control + placebo. In contrast, GM-CSF did not notably improve walking performance, either when used alone or when combined with supervised treadmill exercise. Hence, the benefits of exercise were affirmed. Findings did not, however, support using GM-CSF to treat walking impairment in patients with PAD.