Use of PCSK9 inhibitors is not associated with adverse cognitive effects, even among patients who attain very low levels of LDL cholesterol, according to a study in a subgroup of 1,204 patients from the FOURIER trial, a randomized trial of the PCSK9 inhibitor evolocumab added to statin therapy. Data from previous clinical trials had led to concerns that use of PCSK9 inhibitors or the resulting low LDL-cholesterol levels might be associated with cognitive deficit. However, this study found no significant differences in the change in cognitive function test scores from baseline over a median of 19 months between the placebo and evolocumab groups, including the score on the spatial working memory strategy index of executive function (the primary end point; P <0.001 for noninferiority; P = 0.85 for superiority), and the secondary end points of scores of working memory, episodic memory, or psychomotor speed. In addition, an exploratory analysis found no associations between LDL-cholesterol levels and cognitive changes.