The US Food and Drug Administration (FDA) recently announced that Pfizer’s (PFE) smoking cessation aid Chantix (varenicline) could be linked with a small, increased risk of certain cardiovascular adverse events in patients with cardiovascular disease.
The FDA’s announcement was based on a review of data from a randomized, double-blind, placebo-controlled study that was conducted to evaluate the safety and efficacy of Chantix for smoking cessation. The study was conducted with about 700 patients (35 – 75 years old).
While Chantix was found to be effective in helping patients quit smoking and maintain abstinence for about a year, certain cardiovascular events (like angina pectoris, non fatal myocardial infarction, need for coronary revascularization, and new diagnosis of peripheral vascular disease or admission for a procedure for the treatment of peripheral vascular disease) were reported more frequently in the Chantix arm compared to placebo.
The FDA said that the safety event would be added to the Warnings and Precautions section of Chantix’ label. Moreover, the patient Medication Guide for Chantix will also be updated with the latest information.
The FDA said that it continues to study the cardiovascular safety of Chantix and has asked Pfizer to conduct a large, combined analysis (meta-analysis) of randomized, placebo-controlled trials.
Warning to Impact Sales
Chantix was approved by the FDA in May 2006. US sales of the product have been hit ever since Pfizer updated the product label in 2008 to include a potential relationship between Chantix use and neuropsychiatric symptoms. US sales of Chantix declined 15% to $330 million in 2010.
On July 1, 2009, the FDA announced a Boxed Warning for Chantix’ label highlighting the risk of serious mental health events including changes in behavior, depressed mood, hostility, and suicidal thoughts when taking the drug. A similar warning was added to Zyban, GlaxoSmithKline’s (GSK) smoking cessation drug.
We believe the latest warning (regarding cardiovascular risk) will have a further adverse impact on US sales of Chantix.
Neutral on Pfizer
We currently have a Neutral recommendation on Pfizer, which carries a Zacks #3 Rank (short-term Hold rating). 2011 should be a catalyst-filled year for the company, which is expecting to present phase III data on several candidates. However, Pfizer will face additional challenges later this year with the loss of US exclusivity on Lipitor in November.
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