Varenicline : Where are we today ?

In 2006, Chantix (varenicline) splashed boldly onto the nicotine cessation medication scene with full Food and Drug Administration (FDA) approval following the completion of three distinct Pfizer-funded clinical trials (Jorenby et al., 2006; Gonzales et al., 2006; Tonstad et al., 2006). Almost immediately, however, and contrary to the initial findings supporting the safety and efficacy of varenicline, news reports and other information began to surface asserting that this new smoking cessation aid appeared to have some serious psychiatric side effects (ABC Good Morning America, 2007; Moore, Cohen, Furberg, 2008). These reports along with others prompted the FDA in November of 2007 to impose requirements for the addition of specific warnings and patient instructions on Chantix. In 2009, a black box warning was placed on varenicline (FDA, 2007; FDA, 2009). Pfizer had once envisioned Chantix taking its place alongside the pantheon of the drug maker’s other highly successful products, Lipitor, Celebrex, and Viagra. Instead, Chantix sales declined 15% to $155 million by the third quarter in 2009 (Pierson, Berkrot, 2010); and lawsuits have proliferated (Faulk, 2012). And just when we thought that we knew all about varenicline and contrary to the clinical trial that found no elevated cardiovascular risk compared to placebo (Rigotti, 2010), Sonal Singh and colleagues published the results of a meta-analysis reporting that the cardiovascular side effects for this medication were much greater than previously reported (Singh et al., 2011). Yet within eight months of the Singh study, researchers at the University of California San Francisco (UCSF) also published a meta-analysis of their own showing that varenicline did not have significant or clinically meaningful cardiovascular risks associated with its use (Prochaska and Hilton, 2012). These authors challenged the methods of the Singh meta-analysis and thus threw into doubt the previous findings. And as the Singh / Prochaska debate continues, investigators across the country continue to publish clinical trials results that show that varenicline is safe and efficacious among most populations (Williams et al, 2012; Wong et al., 2012; Pachas et al., 2012).