Introduction: Many patients with primary hypercholesterolemia do not achieve their plasma low-density lipoprotein cholesterol (LDL-C) goals with statin alone under a recommended dose of statin (e.g., 10 mg rosuvastatin) in China. The objective of this phase III study was to evaluate the efficacy and safety of a new singlepill combination (SPC) of rosuvastatin 10 mg/ ezetimibe 10 mg (R10/E10) in this population. Methods: This was a randomized, double-blind, double-dummy, active-controlled study in patients with primary hypercholesterolemia inadequately controlled with statin alone. The participants were randomized 1:1 to receive SPC R10/E10 or R10. The primary objective was to demonstrate the superiority of SPC R10/E10 vs. R10 in reducing the LDL-C levels after 8 weeks. Results: This trial randomized 305 participants to SPC R10/E10 (n = 153) and R10 (n = 152). The superiority of SPC R10/E10 over R10 was demonstrated with the least square (LS) mean difference of percent change in LDL-C from baseline to week 8: -13.85% (95% confidence interval [CI] -20.15% to -7.56%, P \ 0.0001). The proportion of participants who achieved the LDL-C target (\ 2.6 mmol/l) at week 8 was larger with SPC R10/E10 (n = 80, 54.1%) than with R10 (n = 42, 29.2%) (Odds ratio = 2.80, 95% CI 1.70 to 4.61, P \ 0.0001