Among the "adverse events" were 224 cases of potential heart-rhythm disturbances and 148 reports of vision disturbance.
In the commentary he submitted last year to the FDA which was also published in the journal Current Medical Research and Opinion — the same one in which the Pfizer study appeared — Spangler cited one case of cataracts and cases of heart problems in study subjects among his concerns.
"On active drug, one patient developed bilateral subcapsular cataracts (deemed to be drug related by the investigators, including the investigator who actually examined the patient); and two patients developed coronary artery disease events," Spangler's May 2007 commentary reads.
Moreover, Spangler notes that additional cardiac events were mentioned by the study's researchers — but they did not elaborate on the nature of these other adverse events.
"In this situation in particular, we're talking serious adverse events — cardiovascular events," Spangler says. "If you're putting someone on a drug that causes cardiac effects — especially if they're already at higher risk of such effects — you're doing them harm. You then have to do a risk-benefit study to see if the harm is greater than the benefit."
In addition to contacting the major medical journals, Spangler also sent several e-mails to the FDA at the time. In a May 2, 2007 e-mail Spangler outlined his concerns with the size of the study and the authors handling of their data. But it remains unclear what action, if any, the FDA took.
"The FDA has been taking a close look at the reports of adverse events that have been coming in," said FDA spokesperson Susan Cruzan. She added that any study done by Pfizer on Chantix would have had to have been sent to the FDA for review at the time that it was published, according to FDA policy regarding studies done by drug manufacturers.
Even with the new report, DiFranza says it would be premature to sound the alarm bell, particularly on a drug that he says has shown a great degree of effectiveness in helping smokers quit their deadly habit.
A spike in adverse events could be the results of lawyers soliciting for those who say they have been harmed by the drug. Plus, he adds that the rate of reported adverse events remains low, considering that 6 million prescriptions for the drug have been written so far.
And Subbiah notes that, when considered alongside other, larger safety studies that have been done on Chantix, the rates of adverse events were fairly comparable. She adds that the study is only one of numerous safety studies on Chantix, which when combined have looked at a total of more than 3,500 patients.
But last year's relatively small study is thus far the only one to look at safety in patients taking the drug for a year. And Spangler says his biggest concern is how this study is being used.
"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."
And he says that the lack of response to his concerns by Pfizer and the FDA underscores what could be a hidden public health threat when it comes to drug safety.
"It turned out my only recourse was a letter to the editor in an obscure journal with no press coverage," Spangler says. "It's wrong, because I turned out to be right.
"There needs to be some way for the dissenting voices to be heard and for the FDA to respond much more proactively."