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By Kate Kelland
LONDON, Sept 7 (Reuters) - Pfizer's stop-smokingdrug Chantix does not raise risks of heart attack or depression,contrary to previous reports, and should be recommended to moresmokers wanting to quit, scientists said on Monday.
In a study tracking 150,000 smokers in England for 6 months,researchers found that patients who took Chantix, knowngenerically as varenicline and marketed as Champix in Europe,were no more likely to suffer a heart attack than those usingnicotine replacement therapy or another quit-smoking drug.
They were also not at higher risk of depression orself-harm, the study found.
Describing the study as an "extensive analysis" of thepotential risks of Chantix, Aziz Sheikh, professor andco-director at the University of Edinburgh's Centre for MedicalInformatics, said he considered it "highly unlikely thatvarenicline has any significant adverse effects on cardiac ormental health".
"Regulators such as the United States Food and DrugAdministration (FDA) should review its safety warning inrelation to varenicline as this may be unnecessarily limitingaccess to this effective smoking cessation aid," he said.
Chantix reduces both the craving for and pleasurable effectsof cigarettes and is used by heavy smokers who find it difficultto quit. It is one of the biggest-selling stop-smoking drugs inthe United States and Britain, and generated $647 million inrevenue in 2014.
Investors had high hopes for the drug when Pfizer firstlaunched it in 2006, but reports of mental health problems inusers led FDA officials to order a "black box" warning on thedrug's label in 2009. Two years later, the FDA changed theChantix label further to add a warning of increased heart risksfor people who already have cardiovascular disease.
The latest research, published in The Lancet RespiratoryMedicine journal, studied patients who had been prescribedeither varenicline or Zyban, an anti-smoking drug fromGlaxoSmithKline known generically as bupropion, to helpthem quit, or had used nicotine therapies such as patches, gumor lozenges.
Daniel Kotz, a professor at Germany'sHeinrich-Heine-University Dusseldorf who also worked on thestudy, said the findings suggested the risks were low so thebenefits of Chantix should be made more widely available.
"Smokers typically lose three months of life expectancy forevery year of continued smoking," he said. "Our researchsupports the use of varenicline as an effective and safe tool tohelp people quit."
Smoking kills up to half of those who do it and is predictedto claim up to eight million lives a year worldwide by 2030 ifcurrent trends persist. (Editing by Clelia Oziel)
