Project Summary/Abstract Cardiovascular disease remains the leading cause of morbidity and mortality for both men and women, accounting for nearly 40% of annual deaths. High levels of LDL-C and low levels of HDL-C are well-known risk factors for heart disease. Although lowering low-density lipoprotein cholesterol (LDL-C) levels using a number of marketed drugs, of which statins are the leading drugs, has significantly reduced coronary artery disease, substantial residual cardiovascular risk remains, even with very aggressive reductions in levels of LDL-C. Accordingly, attention is now shifting toward strategies for targeting HDL-C as adjunctive therapy to prevent and treat cardiovascular disease. Many studies have emphasized that the risk factor associated with low levels of HDL-C is independent of that of high LDL-C. Recent epidemiological data confirmed that patients with low HDL-C level are at high risk of premature cardiovascular disease no matter how low the LDL-C level. These and other patients will dramatically benefit from an aggressive treatment of low HDL-C. The long-term goal of the proposed studies is to develop novel drugs for increasing HDL-C. Our therapeutic target is endothelial lipase (EL), a member of the lipoprotein lipase gene family that hydrolyzes HDL-C phospholipids. Recent studies demonstrated that inhibition of EL in mice results in a significant increase in HDL-C levels. In Phase I, we have identified selective inhibitors of EL and developed preliminary SAR. As part of this Phase II proposal, we plan to expand and optimize our hits, and confirm the ability of selected compounds to increase the HDL-C level using in vivo animal models.