New research shows that the smoking-cessation drug varenicline may help certain smokers quit, although some say the findings are tempered by the fact that most of the researchers have financial relationships with drug maker Pfizer.

The Wall Street Journal reported July 5 that Pfizer is planning to start marketing varenicline this month under the brand name Chantix. Three new studies have found that users of the drug were more likely to successfully quit smoking, but the findings were limited by the fact that people with depression, alcohol or other drug dependence, and diabetes were excluded from the study.

A study from the University of Wisconsin found that 43.9 percent of Chantix patients were able to quit smoking by the latter third of a 12-week study period, compared to 29.8 percent taking bupropion (Zyban or Wellbutrin) and 17.6 percent of those taking a placebo. Other research found that about 10 percent more Chantix patients remained abstinent after a year compared to a placebo group.

Critics noted that the majority of researchers involved in the study took consulting fees, honoraria, or research grants from Pfizer, but the researchers involved said the studies were all peer-reviewed.

The studies were published in the July 5, 2006 issue of the Journal of the American Medical Association.