Cases of suicidal thoughts and aggressive, erratic behaviour have emerged for people who are taking Pfizer’s new drug, Chantix, to help them quit smoking, US medicine regulators said on Tuesday.
The Food and Drug Administration said it was reviewing cases of suicidal behaviour submitted by the US drugmaker, as well as other similar reports. It added that it was also reviewing reports of drowsiness in Chantix users.
The FDA’s “early communication” on an “ongoing safety review” for Chantix highlights the agency’s changes and disclosure of potential emerging risks following the controversy over Vioxx, the painkiller from US drugmaker Merck that was withdrawn three years ago. The withdrawal of Vioxx due to heart risks triggered a controversy over the drug safety regimes of the FDA and the drug industry. The FDA pledged to become more proactive in its risk communication of possible new drug risks and side effects.
The FDA said the role of Chantix was “not clear” in suicidal cases, because quitting smoking can exacerbate existing psychiatric symptoms, and create nicotine withdrawal symptoms.
Pfizer and its investors have high hopes for Chantix to become a blockbuster drug and a dominant treatment for smoking cessation.
Chantix has generated about $600m (£290m) in sales so far this year, with $241m in the third quarter. New prescriptions for Chantix continue to increase at a robust rate, so investors would be concerned with any safety problems.
James Kelly, analyst at Goldman Sachs, said: “It will be key to watch physician behaviour in the wake of this public disclosure, as well as the FDA’s future communications, based on additional data and analysis provided by Pfizer.”
This is clearly an important growth driver for Pfizer,” he said.