In a statement, Pfizer said that the reliable science on varenicline (Chantix/Champix), involving more than14 clinical trials with more than 7,000 smokers, and the medicine’s approval by regulatory authorities around the world, demonstrate the importance of the medicine as an effective and appropriate treatment option for adult smokers wanting to quit.
Pfizer stands behind the benefit/risk profile of Chantix.
The company expressed concerns about the reliability of the meta-analysis published by Singh et al in the Canadian Medical Association Journal (CMAJ). These concerns, among others, are related to the appropriateness of the authors’ measure of cardiovascular risk, or composite endpoint, which combines events that do not share a common biological cause; the manner in which cardiovascular events were counted and classified; and a small number of events, which forms the authors’ conclusions.
“Pfizer scientists and doctors continuously evaluate the benefits and risks of its medicines, including Chantix,” says Gail Cawkwell, MD, vice president of medical affairs. “The currently available safety data on Chantix, including a pooled analysis of clinical data in 7,375 people trying to quit smoking, do not support an increased cardiovascular risk associated with Chantix.”
Pfizer is discussing with the U.S. Food and Drug Administration (FDA) a protocol to conduct a meta-analysis of Pfizer’s clinical trial data to help further evaluate the cardiovascular safety of Chantix, which will address a number of limitations in the Singh analysis. Pfizer expects that it will be based on a more reliable composite endpoint to measure cardiovascular risk, as well as a validated process to classify, or adjudicate, cardiovascular events that are part of the composite endpoint.
Release Date: July 4, 2011
Filed Under: Drug Discovery