A monthly cholesterol shot can reduce patients' levels by up to 66 percent, according to a new study described at a U.S. cardiology conference.

Fifty one patients received a shot of the drug AMG 145 once every two weeks or every month, depending on the amount of cholesterol lowering drugs they were already taking.

Patients taking the cholesterol shot ever two weeks saw their 'bad cholesterol' LDL, decrease an average of 63 percent by the eighth week.

Patients taking the drug every four weeks, or monthly, saw slightly higher results, with their cholesterol decreasing 66 percent.

No deaths or side effects were reported in the phase 1 study.

The cholesterol shot is made by US biotech firm Amgen. The drug works so well because it is a fully human monoclonal antibody that inhibits PCSK9, a protein that reduces the liver's ability to remove LDL cholesterol from the blood, according to AFP.

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 to AFP.

Phase 2 of the study will begin later this year. The cholesterol shot would be ideal for those whose high cholesterol cannot be controlled with existing therapies, said Harper.

High LDL cholesterol leads to strokes and heart attacks, which is the leading cause of death in the U.S.  Patients can lower their LDL levels with diet and exercise as well as medication.