A new experimental type of cholesterol-lowering drugs might prove to be the most significant advance in controlling the levels of LDL cholesterol since the introduction of statins more than two decades ago. A number of studies on the drugs, known as PCSK9 inhibitors, were presented on March 29 and 30 at the American College of Cardiology annual meeting in Washington, DC.
The presentations included five clinical trials by Amgen Inc., one from Sanofi and its partner Regeneron Pharmaceuticals Inc., and another from Pfizer Inc. The companies are competing in a market that includes millions of patients who are unable to control their cholesterol with statins. The studies have reported reductions in LDL cholesterol levels by one-half to two-thirds among different groups of patients. Elevated LDL or bad cholesterol is a major risk factor for heart attack and stroke. The results presented over the weekend are consistent with promising findings from earlier, smaller studies of PCSK9 inhibitors. Patients enrolled in the studies have been followed for up to one year, and to date, no significant safety issues have been found. However, a number of cardiologists have noted that it is too soon to determine whether the significant reductions in LDL will translate into measurable reductions in cardiovascular disease (heart attacks and strokes). The aforementioned companies have initiated major clinical studies to address the issue; however, results probably will not be available until 2018. In addition, the drugs will require Food and Drug Administration (FDA) approval before they can become available on the marketplace.
PCSK9 inhibitors work by a different mechanism than that of statins. They are bioengineered antibodies that block the PCSK9 protein, which lowers with LDL clearance from the body. Another difference from statins is that the drugs are given as injections; thus, the drug companies are evaluating biweekly and monthly regimens. The PCSK9 inhibitors under evaluation include Amgen's evolocumab, alirocumab from Sanofi and Regeneron, and Pfizer's bococizumab.
Take home message:
Although PCSK9 inhibitors appear promising, only time will tell whether they are superior or inferior to statins already on the marketplace. All medications possess side-effects and a possibility of adverse events. For example, statins have been reported to have side-effects in some individuals, including type 2 diabetes and memory problems.