Six panelists voted to modify (but not weaken) the language in the boxed warning, and most recommended that the last few lines about the health benefits of quitting smoking be removed and argued that the wording had a promotional tone and did not belong in a boxed warning. Several panelists recommended adding sleep disruption and disorders, and recognized adverse events of the drugs to the boxed warning.
Dr. Jeanmarie Perrone
Among those who voted to retain the boxed warning, Dr. Jeanmarie Perrone, director of the medical toxicology division in the emergency medicine department at the University of Pennsylvania, Philadelphia, said there was biologic plausibility for these events. Her biggest concern, she said, was that removing the boxed warning might be interpreted as “an endorsement of safety and that has not been demonstrated.” In the emergency department, she said, she sees many patients who have been prescribed varenicline “by a myriad of clinicians,” and the presence of a boxed warning helps keep this safety issue in mind.
Dr. Rajiv N. Rimal, professor and chair of the department of prevention and community health, George Washington University, Washington, who voted to retain the warning with modified wording, said: “I heard enough compelling evidence to suggest that even some of the more rare events were severe enough” that revisiting the labeling change would be necessary once the other data became available.
Varenicline, approved by the FDA in 2006 as an aid to smoking-cessation treatment, provides a “low level” of dopamine release as people try to quit smoking, according to Pfizer. The boxed warning was added to the label in July 2009, based on the FDA’s review of spontaneous adverse event reports, conducted after an alert about suicidality reports associated with the drug from European regulators about 1 year after FDA approval. About the same time, there was a widely publicized case of a Texas musician who was taking varenicline and was shot and killed by a neighbor while exhibiting uncharacteristic aggressive behavior in the fall of 2007.
The reports provided by the company at that time included 102 suicide-related cases, and 525 reports of aggressive/irrational behavior. A review of the reports in the FDA’s adverse events database included many cases with “hallmarks of drug relatedness,” patients reporting unusual symptoms with “similar distinctive language,” and positive dechallenges and rechallenges, said Dr. Celia Winchell, the medical team leader of addiction products in the FDA’s division of anesthesia, analgesia, and addiction products. Not all cases involved suicidality, depression, or aggression. Postmarketing reports have provided a “rich narrative with detail” about patient experiences, including descriptions that are relatively easy to describe or classify, such as suicide and aggression, while others “defy coding,” such as one person who reported feeling “like a zombie,” she told the panel.