An expert in smoking cessation programs says Pfizer brushed aside his concerns a year ago about possibly dangerous side effects from long-term use of Chantix, ABCNews.com reports. John Spangler, who directs the Tobacco Intervention Programs at Wake Forest University School of Medicine, says a study (look here) cited by Pfizer for one-year usage had a small sample size and side effect data was ignored.

“It would be like me balancing my checkbook without looking at any of the checks I wrote or the deposits I made. They’ve got to look at the data,” he tells ABCNews.com, adding the researchers ignored possible safety signals. “When I did the inferential calculations, I found a relationship (to serious side effects). They had the data, but they didn’t crunch the data at all.” Here’s his letter to the journal editor.

The study was conducted by Pfizer employees, was published in a relatively obscure journal, and has been cited by Pfizer for long-term use, but he says the data doesn’t support the conclusion. [Spangler is a contributor to ABCNews.com, and Curt Furberg, one of the authors of the Institute for Safe Medication Practices report that found nearly 1,000 serious side effects, also works at Wake Forest.]

The authors failed to mention that study subjects who took the drug were 2.5 times as likely to experience a serious adverse event, Spangler tells ABCNews.com. These may have been due to chance, but the small size of the study makes it impossible to draw any firm conclusion, he says, and until a larger study of one-year use is done, docs must consider the possibility of an increased risk

Pfizer tells ABCNews.com that even though the study concludes that it is safe to take the drug for 52 weeks straight, the package labeling suggests a course of 12 weeks, followed by another 12-week course if the patient is not successful in quitting. “It is very important to separate what’s in the scientific literature from what’s in the label,” Ponni Subbiah, Pfizer’s vp of medical affairs, tells ABCNews.com. “Where (doctors) should get prescribing information is from the label.”

But one Pfizer consultant admits the Pfizer study may have been too small to confirm long-term safety. “What (Spangler) says is that the study was underpowered. It means the study’s too small…That’s a valid point,” Joe DiFranza, professor of family medicine and community health at the University of Massachusetts Medical School, tells ABCNews.com.

“I would think that the FDA would look at this and demand a larger study before approving Chantix for long-term use; I would be surprised if they were given the go-ahead to market Chantix for 12 months based on this study.”

ABCNews.com notes the FDA hasn’t demanded a one-year study ad Pfizer has yet to seek FDA approval to change its label to allow long-term use. But at least eight subsequent studies on Chantix - appearing in journals such as Annals of Internal Medicine and the Proceedings of the National Academy of Sciences - have cited the Pfizer study to support safe, long-term use.

“I think it reveals that it is easy to put studies in low-level journals and say something just wrong, not true, that has no statistical basis whatsoever or scientific basis whatsoever,” he notes. “The authors were making a false claim that was not justified by the data that had been published under the title of long-term safety,” Spangler tells ABCNews.com. “It turned out my only recourse was a letter to the editor in an obscure journal with no press coverage. It’s wrong, because I turned out to be right.”

Here’s the full story….

Hat tip to Pharmagossip

The nice photo montage is from ABCNews.com