A monthly injection of an experimental drug made by the US biotech firm Amgen reduced patients’ cholesterol by up to 66 percent, according to a small study described at a US cardiology conference. The early phase 1 clinical trial, designed mainly to see if the treatment was safe, followed 51 patients who received a shot of the drug, AMG 145, either once every two or every four weeks. Among trial subjects were already taking high doses of cholesterol-lowering drugs, known as statins, and who got the shot every two weeks, the dangerous type of cholesterol (LDL) in their bodies dropped by an average of 63 percent by the eighth week. And those who were on low doses of statins and received the drug every four weeks saw a slightly higher average drop in LDL cholesterol — 66 percent by the end of the same time period. No deaths or adverse events were recorded during the preliminary study, which was presented for the the first time on Sunday at the American College of Cardiology annual conference. The drug is a fully human monoclonal antibody that inhibits PCSK9, a protein that reduces the liver’s ability to remove LDL cholesterol from the blood. “Early studies have shown that AMG 145 lowers levels of PCSK9 in the body and brings LDL-cholesterol levels down as a result,” said a statement by Sean Harper, executive vice president of Research and Development at Amgen. “Based on these results, Amgen initiated a robust phase 2 program that will provide a deeper understanding of the benefit-risk profile of inhibiting PCSK9 in a wide variety of patients whose high cholesterol cannot be controlled with existing therapies.” More data from the phase 2 study is expected later this year. Finding alternate ways to treat high cholesterol is important for many patients who either cannot tolerate statin therapy or who have difficulty getting their cholesterol counts low enough with diet changes and contemporary statins. High LDL cholesterol is a leading factor in the development of heart disease and is considered a major public health issue worldwide.