National Cancer Institute NCI Cancer Bulletin: A Trusted Source for Cancer Research News
June 28, 2011 • Volume 8 / Number 13

FDA Update

Potential Cardiac Risks Associated with Smoking Cessation Drug

The Food and Drug Administration (FDA) has updated the prescribing information label on the smoking-cessation drug varenicline (Chantix) to warn that the drug may increase the risk of certain cardiac events in people with underlying cardiovascular disease.

The change is based on findings from a clinical trial of 700 smokers who have cardiovascular disease, according to a safety announcement issued by the FDA on June 16. Trial participants were randomly assigned to receive varenicline or a placebo for 12 weeks and were then followed for an additional 40 weeks without treatment. Although cardiac events “were infrequent overall,” the agency noted that “certain events, including heart attack, were reported more frequently in patients treated with Chantix than in patients treated with placebo.”

Other cardiac events included small increased risks of chest pain, the need for coronary revascularization procedures, and peripheral vascular disease. The two most common events in patients taking varenicline were nonfatal heart attacks (7 versus 3 among those taking the placebo) and coronary revascularization procedures (8 versus 3). Five of the seven patients who required a revascularization procedure were from the same group of participants who had had a nonfatal heart attack.

Physicians should be aware of these risks and discuss the benefits and potential risks of varenicline with their patients who have heart disease, the agency stated in the announcement. In July 2009, the FDA added a “black box” warning about the increased risks of neuropsychiatric symptoms associated with their use to the labels of varenicline and another smoking cessation drug, bupropion (Zyban).

Diabetes Drug May Increase Risk of Bladder Cancer

Use of the diabetes drug pioglitazone (Actos) for more than 1 year may increase the risk of developing bladder cancer, according to a June 15 safety announcement from the FDA.

The announcement is based on a 5-year interim analysis of a 10-year prospective cohort study of safety data being conducted by the drug’s manufacturer, Takeda Pharmaceuticals. The study includes more than 193,000 patients who are part of the Kaiser Permanente Northern California health plan. All patients in the study are 40 years of age or older and have been diagnosed with diabetes.

No overall increase in bladder cancer risk was seen in those using pioglitazone compared with those who had never taken the drug. Patients who had been taking the drug for 12 to 24 months, however, had a 40 percent higher risk of developing bladder cancer than people who had never taken it. 

“Although there was no overall increased risk of bladder cancer with pioglitazone use, an increased risk of bladder cancer was noted among patients with the longest exposure to pioglitazone, and in those exposed to the highest cumulative dose of pioglitazone,” the FDA reported.

French health officials recently announced similar findings from a much larger retrospective study of 1.2 million patients taking pioglitazone. Based on the finding, health officials in France halted the use of pioglitazone. In addition, German health officials have ordered clinicians not to prescribe the drug to new patients.

The FDA has advised U.S. physicians not to prescribe pioglitazone for patients with bladder cancer and to use it “with caution” in those who have been treated previously for bladder cancer. “The benefits of blood sugar control with pioglitazone should be weighed against the unknown risks for cancer recurrence,” the agency stated.