A drug that fights inflammation called canakinumab has been found in a study to reduce the risk of heart attacks and strokes in people who have already had one. Canakinumab is already marketed under the brand name Ilaris and has been approved to treat a type of juvenile rheumatoid arthritis and other rare disorders. The New England Journal of Medicine recently published the cardiovascular results of the study. The study was paid for by Novartis (NYSE:NVS), which makes the drug.

The Novartis drug is much stronger and works faster than familiar anti-inflammatory medicines, like aspirin and ibuprofen, by suppressing a substance called interleukin-1β, which causes systemic inflammation. Researchers have long suspected inflammation of playing a role in cardiovascular disease and cancer. About half of people who have heart attacks have normal cholesterol levels. Cholesterol-lowering statin medicines typically used in the treatment of cardiovascular disease can also reduce inflammation, but not always as much as canakinumab.

The new study included 10,061 participants from 39 countries, with an average age of 61 and blood tests showing high levels of inflammation. A quarter of the participants were women and 40 percent of the participants had been diagnosed with diabetes. In addition to their usual statins and other heart medicines, the participants were randomly chosen to receive either a placebo or an injection of canakinumab every three months. Three different doses of the new drug were tested.

The researchers found that in the group who received the optimal dose of canakinumab, out of every 100 patients followed for a year, 3.86 had a heart attack, a stroke, or died from cardiovascular disease. In those who were given the placebo, the rate was higher at 4.5. The patients were treated for a median of 3.7 years. When the length of time patients were treated was factored in, the reduction in risk was 15 percent.

Dr. Paul M. Ridker, the first author of the study and director of the Center for Cardiovascular Disease Prevention at Brigham and Women’s Hospital in Boston, said, This is the first evidence we have that if you inhibit this inflammatory process without changing cholesterol at all, you’re getting a risk reduction.” Researchers outside the study say the findings represent a major milestone. Cardiovascular disease is the leading cause of death worldwide. Globally, it killed 15 million in 2015, with 634,000 of those deaths occurring in the United States.

Experts cautioned that potentially fatal side effects from the drug mean it is unlikely that it will become widely used. Because the drug suppresses part of the immune system, it increases the risk of infections. In the study, 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.

The high cost of the drug may also be an obstacle to widespread adoption. It costs about $200,000 a year. The company declined to say whether the price would change if the drug received approval for use in the treatment of heart disease.