The drug that was studied, canakinumab, is already marketed under the brand name Ilaris, but was approved to treat a type of juvenile rheumatoid arthritis and other rare disorders, not heart disease. It costs about $200,000 a year and is made by Novartis, which paid for the new study. The company declined to say whether the price would change if the drug came into more general use for heart disease.

The drug works differently from the cholesterol-lowering statin medicines that have become mainstays in treating and preventing heart disease. Unlike statins, it has no effect on cholesterol. Instead, it reduces inflammation — the response by the immune system to injury or infection — which researchers have long suspected of playing a role in cardiovascular disease and cancer. About half of people who have heart attacks have normal cholesterol levels, and researchers think that in some of them, inflammation may contribute to heart and artery disease.

But because the drug suppresses part of the immune system, it increases the risk of infections, including fatal ones. Deaths from infection in the study appeared to match lives saved by the drug, so there was no difference in overall mortality between the groups that got the drug and the placebo.

An editorial by Dr. Robert A. Harrington of Stanford University in The New England Journal of Medicine, which published the cardiovascular results of the study on Sunday, described the cardiovascular benefit as “modest,” called for more information about the fatal infections and said the drug was too expensive to be used in such a common disease.

Dr. Eric Peterson, a cardiologist and the director of the Duke Clinical Research Institute at Duke University, also said he thought the drug would not be widely used, but added, “There might be ways to develop other drugs that could be safer and cheaper to lower inflammation.”