Measuring treatment effects of cilostazol on clinical trial endpoints in patients with intermittent claudication.

Intermittent claudication (IC) comprises the most common presenting symptoms of peripheral arterial disease (PAD), which itself is a manifestation of systemic atherosclerosis. Typical symptoms of IC are aching pain, numbness, and fatigue in the lower extremities. Symptoms are induced by walking or exercise and usually resolve with rest. The cornerstone of treating IC is risk-factor reduction and a supervised exercise regimen. Pharmacotherapy specifically indicated for the treatment of IC includes a new drug, cilostazol, and the traditional drug, pentoxifylline. Cilostazol also has antiplatelet, antithrombotic, and vasodilatory activity, as well as a positive effect on serum lipids. Eight multicenter clinical trials, seven in the U.S. and one in the U.K., used objective and subjective clinical endpoints to assess the treatment efficacy of cilostazol. Objective endpoints included maximal and pain-free walking distance (MWD and PFWD, respectively), the ankle-brachial index, peripheral hemodynamic measurements, and serum lipid levels. Subjective endpoints, assessed by patient questionnaires, included perceived functional status and health-related quality of life. Cilostazol treatment showed statistically significant increases in MWD and PFWD within 4 weeks, as well as improvements in physical functional status at 24 weeks, compared with placebo and pentoxifylline. Increases in high-density lipoprotein cholesterol and decreases in plasma triglycerides were also noted. Subjective assessments appeared to match objective parameters.