A drug used to treat chronic myeloid leukemia (CML) may be a cause of atherosclerosis in some patients. Atherosclerosis—sometimes known as “hardening of the arteries”—is a disorder of the arteries caused by a build-up of internal plaque.

This reduces blood flow and thus nutrient and oxygen supply to the brain, heart, organ systems, and extremities of the body. It can be very life-threatening.

In April 2013, Health Canada issued a public communication concerning the possibility that Tasigna—known generically as nilotinib—had been linked to atherosclerosis and related vascular conditions such as peripheral artery occlusion disease (PAOD), femoral artery stenosis, coronary artery stenosis, carotid artery stenosis, and stroke.

PAOD and femoral artery stenosis is a narrowing of the arteries that specifically supply the lower legs. When the blood supply is reduced, it can pool, become thickened, and produce a blood clot which can completely obstruct the flow and break off and cause a heart attack or stroke.

Coronary artery stenosis is a narrowing of the arteries supplying the heart muscle itself. It can result in episodes of extreme chest pain known as angina. Carotid artery stenosis is a narrowing of the arteries supplying the brain. Reduced flow or occlusion in these arteries is a primary reason for stroke.

The warning produced by Health Canada noted that CML patients should reveal any preexisting conditions which might increase their risk of atherosclerosis in combination with Tasigna treatment such as high blood pressure, cholesterol, glucose, or more generalized heart problems.

The communication noted that close to 300 people were found to have developed atherosclerosis in the manufacturer’s global database in an eight-year period between 2005 and 2013.

Tasigna was approved for commercial use in America by the U.S. Food and Drug Administration (FDA) in 2007. Despite multiple studies which had linked the drug as a possible cause of atherosclerosis in a certain percentage of patients, it reached a high level of popularity with close to $2 billion in sales in 2016.

In fact, in 2013, nine studies were released that indicated a connection between Tasigna and atherosclerosis. After reviewing the data from these studies and being in communication with drug oversight authorities from Canada and the United Kingdom (UK), the FDA finally required that a black box warning for heart issues be added to the label.

Since its commercial approval, Tasigna had had a black box warning for other side effects, but not for life-threatening vascular problems such as atherosclerosis. Since the first study published concerning a possible link between Tasigna and atherosclerosis in 2011 showed 25 percent of patients developing vascular ailments, Novartis—the drug’s manufacturer—has been accused of having the knowledge and suppressing information from its commercial inception.

Multiple lawsuits have been filed by individuals that have experienced severe vascular symptoms after being on Tasigna and suffered amputations, cardiac arrests, or amputations related to these side effects.