Pfizer has received some good news over Champix as regulators in Japan have given the firm the go-ahead to sell the smoking cessation drug.

Champix (varenicline), known elsewhere as Chantix, has been approved by Japan’s Ministry of Health, Labor and Welfare, having been filed there in June 2006 and it was approved on January 25, 2008. The approval was based in part on a 12-week study in Japanese smokers who wanted to quit smoking, which showed that the four consecutive-week cessation rate at the end of the study was 65.4% (85/130 cases) in patients receiving 1mg Champix twice-daily and 39.5% for those on placebo.

The Japanese approval comes at a tricky time for Champix which has recently been the subject of a label update in the USA which warns doctors to keep an eye out for potentially serious neuro-psychiatric symptoms, including behavioural changes, agitation, depression, suicidal ideation and suicidal behaviour. Similar warnings have also been issued in the European Union.

Chantix, a selective nicotinic acetylcholine receptor partial agonist, is the first non-nicotine prescription treatment for smoking cessation in almost a decade. It has proved a huge success for Pfizer and fourth-quarter 2007 sales reached $280 million.