European regulators have removed the black triangle warning from the label of Pfizer's smoking cessation drug Champix, on the back of data from a post-marketing surveillance study backing its neuropsychiatric safety.

Results from the Lancet-published EAGLES trial show that use of Champix/Chantix (varenicline) and buprion (originally GlaxoSmithKline's Zyban but now generically available) is not linked with an increased risk of neuropsychiatric side effects, as was previously feared.

The study's primary safety endpoint was the occurrence of at least one treatment-emergent severe adverse event of anxiety, depression, feeling abnormal, or hostility and/or the occurrence of at least one treatment-emergent moderate or severe adverse event of agitation, aggression, delusions, hallucinations, homicidal ideation, mania, panic, paranoia, psychosis, suicidal ideation, suicidal behaviour or completed suicide.

The incidence of the primary safety endpoint in patients without a history of psychiatric disorders was 1.3 percent for Chantix/Champix, 2.2 percent for buprion, 2.5 percent for the nicotine patch and 2.4 percent for placebo, while the incidence rates in patients with a history of psychiatric disorders were 6.5 percent, 6.7 percent, 5.2 percent and 4.9 percent, respectively.

"Smoking remains a major public health challenge, causing more than 5 million deaths worldwide each year," said Rory O'Connor, chief medical officer, Internal Medicine, Pfizer. "The new safety and efficacy information in the European label further supports the importance of Champix as a treatment option for healthcare providers and for those who are trying to quit smoking."

The findings follow those of separate study, also published in the Lancet but last year, showing that people taking Champix were at no higher risk of depression or suffering a heart attack than those using other drugs or nicotine-replacement therapy.