FDA Questions Pfizers Chantix StudySep 13, 2016
Federal regulators are reviewing Pfizer Inc.'s research concerning the neuropsychiatric effects of Chantix, the smoking cessation drug. Approved in 2006, Chantix received a FDA Black Box label warning in 2009, the agency's most serious warning.
The U.S. Food and Drug Administration (FDA) may not have fully captured the number of adverse events associated with Chantix, which may have led to a possible bias in the research that favored Chantix.
Chantix has been associated with psychiatric side effects since its release, including dozens of reports of suicides and hundreds of reports of suicidal behavior. In 2009, the year the Black Box label was mandated by the FDA, the agency also required that Pfizer conduct additional studies to gain a clearer understanding of the drug's dangerous side effects. The most common side effects associated with Chantix include, abnormal dreams, trouble sleeping, unusual tiredness, and weakness. The Chantix website also lists other possible side effects that include, "hostility, agitation, depressed mood, and suicidal thoughts or actions."
Chantix is a pill that is taken twice daily and is advertised to help users quit smoking. Chantix works by blocking the pleasurable effects of smoking in the brain, which decreases the desire to smoke. Chantix treatment meant to be used in collaboration with behavior modification and counseling.
Most recently, the FDA requested a Chantix clinical trial following reports involving increased rates of suicidal ideation and suicide associated tied Chantix use, according to The Boston Globe. Xyban (bupropion), which is made by GlaxoSmithKline, was also included and is a different drug used in smoking cessation. The FDA is considering if Pfizer may remove the boxed warning on Chantix over possible potential changes in behavior, depressed mood, and suicidal thoughts.
Based on a September 2016 report, the FDA questioned the lack of consistency over how Pfizer's study recorded neuropsychiatric events and posted a report before the meeting, which is scheduled for mid-September and includes external experts. The meeting is being convened to advise the federal regulators about potential changes to the boxed warnings on both Chantix and Zyban, The Boston Globe reported. "The trial was designed in a well-intentioned attempt to capture somewhat ill-defined and complex neuropsychiatric phenomena," FDA staff wrote in the report. "However, many problems in the implementation were apparent upon review of the collected data."
The study revealed increased incidences of neuropsychiatric side effects in individuals who were previously diagnosed with a psychiatric disorder and taking Chantix or Zyban, as well as in patients with no prior diagnosis. The interesting result, noted Bloomberg.com is that, in locations in which doctors received $25,000 or more from Pfizer for their work, a decreased number of patients diagnosed with a psychiatric disorder were reported to have side effects, including anxiety, agitation, hostility, or suicidal thoughts. At locations where physicians received less money, or no money, an increased percentage of patients reported such problems. The Boston Globe noted that 32 trial sites were involved in which researchers received at least $25,000. According to Bloomberg.com, federal regulators note that the money researchers take from pharmaceutical companies may affect their judgment. The FDA pointed out that, at two sites, physicians received "as many as 60 separate honoraria for speaking engagements and consulting fees."