Rare mutations leading to increased function of CETP have been linked to accelerated atherosclerosis. In contrast, a polymorphism (I405V) of the CETP gene leading to lower serum levels has also been linked to exceptional longevity  and to metabolic response to nutritional intervention. However, this mutation also increases the prevalence of coronary heart disease in patients with hypertriglyceridemia. The D442G mutation, which lowers CETP levels and increases HDL levels also increases coronary heart disease.
As HDL can alleviate atherosclerosis and other cardiovascular diseases, and certain disease states such as the metabolic syndrome feature low HDL, pharmacological inhibition of CETP is being studied as a method of improving HDL levels. To be specific, in a 2004 study, the small molecular agent torcetrapib was shown to increase HDL levels, alone and with a statin, and lower LDL when co-administered with a statin. Studies into cardiovascular endpoints, however, were largely disappointing. While they confirmed the change in lipid levels, most reported an increase in blood pressure, no change in atherosclerosis, and, in a trial of a combination of torcetrapib and atorvastatin, an increase in cardiovascular events and mortality.
A compound related to torcetrapib, Dalcetrapib (investigative name JTT-705/R1658), was also being studied, but trials have since been ceased. It increases HDL levels by 30%, as compared to 60% by torcetrapib. Another CETP inhibitor under development is Merck's MK-0859 anacetrapib, which in initial studies is not shown to increase blood pressure.
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